QGIS User Guide - QGIS Documentation

QGIS User Guide - QGIS Documentation

QGIS User Guide

Release 2.6

QGIS Project

22.05.2015

Sisältö

1 Preamble

3

2 Conventions

5

2.1

GUI Conventions

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

5

2.2

Text or Keyboard Conventions

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

5

2.3

Platform-specific instructions

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

6

3 Foreword

7

4 Features

9

4.1

View data

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

9

4.2

Explore data and compose maps

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

9

4.3

Create, edit, manage and export data

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

10

4.4

Analyse data

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

10

4.5

Publish maps on the Internet

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

10

4.6

Extend QGIS functionality through plugins

. . . . . . . . . . . . . . . . . . . . . . . . . . . . .

10

4.7

Python Console

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

11

4.8

Known Issues

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

11

5 What’s new in QGIS 2.6

13

5.1

Application and Project Options

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

13

5.2

Data Providers

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

13

5.3

Map Composer

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

13

5.4

QGIS Server

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

14

5.5

Symbology

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

14

5.6

User Interface

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

14

6 Getting Started

15

6.1

Asennus

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

15

6.2

Sample Data

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

15

6.3

Sample Session

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

16

6.4

Starting and Stopping QGIS

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

17

6.5

Command Line Options

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

17

6.6

Projects

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

19

6.7

Output

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

19

7 QGIS GUI

21

7.1

Menu Bar

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

22

7.2

Toolbar

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

27

7.3

Map Legend

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

27

7.4

Map View

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

30

7.5

Status Bar

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

30

i

8 General Tools

31

8.1

Keyboard shortcuts

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

31

8.2

Context help

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

31

8.3

Rendering

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

31

8.4

Measuring

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

33

8.5

Identify features

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

35

8.6

Decorations

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

36

8.7

Annotation Tools

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

38

8.8

Spatial Bookmarks

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

39

8.9

Nesting Projects

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

41

9 QGIS Configuration

43

9.1

Panels and Toolbars

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

43

9.2

Project Properties

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

44

9.3

Options

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

44

9.4

Customization

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

52

10 Working with Projections

55

10.1 Overview of Projection Support

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

55

10.2 Global Projection Specification

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

55

10.3 Define On The Fly (OTF) Reprojection

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

57

10.4 Custom Coordinate Reference System

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

58

10.5 Default datum transformations

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

59

11 QGIS Browser

61

12 Työskentely vektoridatalla

63

12.1 Tuetut datan formaatit

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

63

12.2 The Symbol Library

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

75

12.3 The Vector Properties Dialog

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

79

12.4 Expressions

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 105

12.5 Editing

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 112

12.6 Query Builder

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 129

12.7 Field Calculator

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 130

13 Working with Raster Data

133

13.1 Working with Raster Data

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 133

13.2 Raster Properties Dialog

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 134

13.3 Raster Calculator

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 142

14 Working with OGC Data

145

14.1 QGIS as OGC Data Client

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 145

14.2 QGIS as OGC Data Server

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 154

15 Working with GPS Data

159

15.1 GPS Plugin

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 159

15.2 Live GPS tracking

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 163

16 GRASS GIS Integration

169

16.1 Starting the GRASS plugin

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 169

16.2 Loading GRASS raster and vector layers

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 170

16.3 GRASS LOCATION and MAPSET

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 170

16.4 Importing data into a GRASS LOCATION

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 172

16.5 The GRASS vector data model

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 173

16.6 Creating a new GRASS vector layer

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 174

16.7 Digitizing and editing a GRASS vector layer

. . . . . . . . . . . . . . . . . . . . . . . . . . . . 174

16.8 The GRASS region tool

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 177

16.9 The GRASS Toolbox

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 177

ii

17 QGIS processing framework

187

17.1 Introduction

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 187

17.2 The toolbox

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 188

17.3 The graphical modeler

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 197

17.4 The batch processing interface

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 203

17.5 Using processing algorithms from the console

. . . . . . . . . . . . . . . . . . . . . . . . . . . 205

17.6 The history manager

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 210

17.7 Writing new Processing algorithms as python scripts

. . . . . . . . . . . . . . . . . . . . . . . . 211

17.8 Handing data produced by the algorithm

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 213

17.9 Communicating with the user

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 213

17.10 Documenting your scripts

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 213

17.11 Example scripts

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 214

17.12 Best practices for writing script algorithms

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 214

17.13 Pre- and post-execution script hooks

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 214

17.14 Configuring external applications

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 214

17.15 The QGIS Commander

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 221

18 Processing providers and algorithms

223

18.1 GDAL algorithm provider

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 223

18.2 LAStools

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 256

18.3 Modeler Tools

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 281

18.4 OrfeoToolbox algorithm provider

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 283

18.5 QGIS algorithm provider

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 358

18.6 R algorithm provider

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 412

18.7 SAGA algorithm provider

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 422

18.8 TauDEM algorithm provider

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 593

19 Print Composer

625

19.1 First steps

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 626

19.2 Rendering mode

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 630

19.3 Composer Items

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 631

19.4 Manage items

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 653

19.5 Revert and Restore tools

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 654

19.6 Atlas generation

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 656

19.7 Creating Output

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 658

19.8 Manage the Composer

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 659

20 Plugins

661

20.1 QGIS Plugins

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 661

20.2 Using QGIS Core Plugins

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 665

20.3 Coordinate Capture Plugin

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 665

20.4 DB Manager Plugin

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 666

20.5 Dxf2Shp Converter Plugin

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 667

20.6 eVis Plugin

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 668

20.7 fTools Plugin

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 678

20.8 GDAL Tools Plugin

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 681

20.9 Georeferencer Plugin

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 684

20.10 Interpolointiliitännäinen

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 688

20.11 Offline Editing Plugin

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 689

20.12 Oracle Spatial GeoRaster Plugin

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 690

20.13 Raster Terrain Analysis Plugin

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 692

20.14 Heatmap Plugin

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 693

20.15 MetaSearch Catalogue Client

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 696

20.16 Road Graph Plugin

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 700

20.17 Spatial Query Plugin

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 701

20.18 SPIT Plugin

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 702

20.19 SQL Anywhere Plugin

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 703

20.20 Topology Checker Plugin

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 703

20.21 Zonal Statistics Plugin

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 707

iii

21 Help and Support

709

21.1 Mailing lists

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 709

21.2 IRC

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 710

21.3 BugTracker

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 710

21.4 Blog

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 711

21.5 Plugins

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 711

21.6 Wiki

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 711

22 Appendix

713

22.1 GNU General Public License

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 713

22.2 GNU Free Documentation License

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 716

23 Literature and Web References

Indeksi

723

725

iv

.

.

QGIS User Guide, Release 2.6

Sisältö 1

QGIS User Guide, Release 2.6

2 Sisältö

LUKU

1

Preamble

This document is the original user guide of the described software QGIS. The software and hardware described in this document are in most cases registered trademarks and are therefore subject to legal requirements. QGIS is subject to the GNU General Public License. Find more information on the QGIS homepage, http://www.qgis.org

.

The details, data, and results in this document have been written and verified to the best of the knowledge and responsibility of the authors and editors. Nevertheless, mistakes concerning the content are possible.

Therefore, data are not liable to any duties or guarantees. The authors, editors and publishers do not take any responsibility or liability for failures and their consequences. You are always welcome to report possible mistakes.

This document has been typeset with reStructuredText. It is available as reST source code via github and online as HTML and PDF via http://www.qgis.org/en/docs/ . Translated versions of this document can be downloaded in several formats via the documentation area of the QGIS project as well. For more information about contributing to this document and about translating it, please visit http://www.qgis.org/wiki/ .

Links in this Document

This document contains internal and external links. Clicking on an internal link moves within the document, while clicking on an external link opens an internet address. In PDF form, internal and external links are shown in blue and are handled by the system browser. In HTML form, the browser displays and handles both identically.

User, Installation and Coding Guide Authors and Editors:

Tara Athan

Peter Ersts

Radim Blazek

Anne Ghisla

Godofredo Contreras Otto Dassau

Stephan Holl N. Horning

Werner Macho Carson J.Q. Farmer Tyler Mitchell

Claudia A. Engel Brendan Morely David Willis

K. Koy

Jürgen E. Fischer

Larissa Junek

Tim Sutton

Astrid Emde

Diethard Jansen

Alex Bruy

Yves Jacolin

Paolo Corti

Raymond Nijssen

Alexandre Neto

Gavin Macaulay

Richard Duivenvoorde

Andy Schmid

Martin Dobias

Magnus Homann

Lars Luthman

Marco Hugentobler

Gary E. Sherman

Andreas Neumann

Hien Tran-Quang

Copyright (c) 2004 - 2014 QGIS Development Team

Internet: http://www.qgis.org

License of this document

.

Permission is granted to copy, distribute and/or modify this document under the terms of the GNU Free Documentation License, Version 1.3 or any later version published by the Free Software Foundation; with no Invariant

Sections, no Front-Cover Texts and no Back-Cover Texts. A copy of the license is included in Appendix

GNU

Free Documentation License .

3

QGIS User Guide, Release 2.6

4 Luku 1. Preamble

LUKU

2

Conventions

This section describes the uniform styles that will be used throughout this manual.

2.1 GUI Conventions

The GUI convention styles are intended to mimic the appearance of the GUI. In general, a style will reflect the non-hover appearance, so a user can visually scan the GUI to find something that looks like the instruction in the manual.

• Menu Options: Layer → Add a Raster Layer or Settings → Toolbars → Digitizing

• Tool:

Add a Raster Layer

• Button : [Save as Default]

• Dialog Box Title: Layer Properties

• Tab: General

• Checkbox: Render

• Radio Button: Postgis SRID EPSG ID

• Select a number:

• Select a string:

• Browse for a file:

• Select a color:

• Slider:

• Input Text:

A shadow indicates a clickable GUI component.

2.2 Text or Keyboard Conventions

This manual also includes styles related to text, keyboard commands and coding to indicate different entities, such as classes or methods. These styles do not correspond to the actual appearance of any text or coding within QGIS.

• Hyperlinks: http://qgis.org

• Keystroke Combinations: Press Ctrl+B, meaning press and hold the Ctrl key and then press the B key.

• Name of a File: lakes.shp

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• Name of a Class: NewLayer

• Method: classFactory

• Server: myhost.de

• User Text: qgis --help

Lines of code are indicated by a fixed-width font:

PROJCS["NAD_1927_Albers",

GEOGCS["GCS_North_American_1927",

2.3 Platform-specific instructions

GUI sequences and small amounts of text may be formatted inline: Click

File QGIS

→ Quit to close

QGIS

. This indicates that on Linux, Unix and Windows platforms, you should click the File menu first, then Quit, while on Macintosh OS X platforms, you should click the QGIS menu first, then Quit.

Larger amounts of text may be formatted as a list:

• Do this

• Do that

• Do something else or as paragraphs:

Do this and this and this. Then do this and this and this, and this and this and this, and this and this and this.

Do that. Then do that and that and that, and that and that and that, and that and that and that, and that and that and that, and that and that and that.

.

Screenshots that appear throughout the user guide have been created on different platforms; the platform is indicated by the platform-specific icon at the end of the figure caption.

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3

Foreword

.

Welcome to the wonderful world of Geographical Information Systems (GIS)!

QGIS is an Open Source Geographic Information System. The project was born in May of 2002 and was established as a project on SourceForge in June of the same year. We’ve worked hard to make GIS software (which is traditionally expensive proprietary software) a viable prospect for anyone with basic access to a personal computer. QGIS currently runs on most Unix platforms, Windows, and OS X. QGIS is developed using the Qt toolkit

( http://qt.digia.com

) and C++. This means that QGIS feels snappy and has a pleasing, easy-to-use graphical user interface (GUI).

QGIS aims to be a user-friendly GIS, providing common functions and features. The initial goal of the project was to provide a GIS data viewer. QGIS has reached the point in its evolution where it is being used by many for their daily GIS data-viewing needs. QGIS supports a number of raster and vector data formats, with new format support easily added using the plugin architecture.

QGIS is released under the GNU General Public License (GPL). Developing QGIS under this license means that you can inspect and modify the source code, and guarantees that you, our happy user, will always have access to a GIS program that is free of cost and can be freely modified. You should have received a full copy of the license with your copy of QGIS, and you also can find it in Appendix

GNU General Public License .

Vihje: Up-to-date Documentation

The latest version of this document can always be found in the documentation area of the QGIS website at http://www.qgis.org/en/docs/ .

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4

Features

QGIS offers many common GIS functionalities provided by core features and plugins. A short summary of six general categories of features and plugins is presented below, followed by first insights into the integrated Python console.

4.1 View data

You can view and overlay vector and raster data in different formats and projections without conversion to an internal or common format. Supported formats include:

• Spatially-enabled tables and views using PostGIS, SpatiaLite and MS SQL Spatial, Oracle Spatial, vector formats supported by the installed OGR library, including ESRI shapefiles, MapInfo, SDTS, GML and many more. See section

Työskentely vektoridatalla .

• Raster and imagery formats supported by the installed GDAL (Geospatial Data Abstraction Library) library, such as GeoTIFF, ERDAS IMG, ArcInfo ASCII GRID, JPEG, PNG and many more. See section

Working with Raster Data .

• GRASS raster and vector data from GRASS databases (location/mapset). See section

GRASS GIS Integration .

• Online spatial data served as OGC Web Services, including WMS, WMTS, WCS, WFS, and WFS-T. See section

Working with OGC Data

.

4.2 Explore data and compose maps

You can compose maps and interactively explore spatial data with a friendly GUI. The many helpful tools available in the GUI include:

• QGIS browser

• On-the-fly reprojection

• DB Manager

• Map composer

• Overview panel

• Spatial bookmarks

• Annotation tools

• Identify/select features

• Edit/view/search attributes

• Data-defined feature labeling

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• Data-defined vector and raster symbology tools

• Atlas map composition with graticule layers

• North arrow scale bar and copyright label for maps

• Support for saving and restoring projects

4.3 Create, edit, manage and export data

You can create, edit, manage and export vector and raster layers in several formats. QGIS offers the following:

• Digitizing tools for OGR-supported formats and GRASS vector layers

• Ability to create and edit shapefiles and GRASS vector layers

• Georeferencer plugin to geocode images

• GPS tools to import and export GPX format, and convert other GPS formats to GPX or down/upload directly to a GPS unit (On Linux, usb: has been added to list of GPS devices.)

• Support for visualizing and editing OpenStreetMap data

• Ability to create spatial database tables from shapefiles with DB Manager plugin

• Improved handling of spatial database tables

• Tools for managing vector attribute tables

• Option to save screenshots as georeferenced images

4.4 Analyse data

You can perform spatial data analysis on spatial databases and other OGR- supported formats. QGIS currently offers vector analysis, sampling, geoprocessing, geometry and database management tools. You can also use the integrated GRASS tools, which include the complete GRASS functionality of more than 400 modules. (See section

GRASS GIS Integration .) Or, you can work with the Processing Plugin, which provides a powerful geospatial

analysis framework to call native and third-party algorithms from QGIS, such as GDAL, SAGA, GRASS, fTools and more. (See section

Introduction .)

4.5 Publish maps on the Internet

QGIS can be used as a WMS, WMTS, WMS-C or WFS and WFS-T client, and as a WMS, WCS or WFS server.

(See section

Working with OGC Data .) Additionally, you can publish your data on the Internet using a webserver

with UMN MapServer or GeoServer installed.

4.6 Extend QGIS functionality through plugins

QGIS can be adapted to your special needs with the extensible plugin architecture and libraries that can be used to create plugins. You can even create new applications with C++ or Python!

4.6.1 Core Plugins

Core plugins include:

1. Coordinate Capture (Capture mouse coordinates in different CRSs)

2. DB Manager (Exchange, edit and view layers and tables; execute SQL queries)

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3. Diagram Overlay (Place diagrams on vector layers)

4. Dxf2Shp Converter (Convert DXF files to shapefiles)

5. eVIS (Visualize events)

6. fTools (Analyze and manage vector data)

7. GDALTools (Integrate GDAL Tools into QGIS)

8. Georeferencer GDAL (Add projection information to rasters using GDAL)

9. GPS Tools (Load and import GPS data)

10. GRASS (Integrate GRASS GIS)

11. Heatmap (Generate raster heatmaps from point data)

12. Interpolation Plugin (Interpolate based on vertices of a vector layer)

13. Offline Editing (Allow offline editing and synchronizing with databases)

14. Oracle Spatial GeoRaster

15. Processing (formerly SEXTANTE)

16. Raster Terrain Analysis (Analyze raster-based terrain)

17. Road Graph Plugin (Analyze a shortest-path network)

18. Spatial Query Plugin

19. SPIT (Import shapefiles to PostgreSQL/PostGIS)

20. SQL Anywhere Plugin (Store vector layers within a SQL Anywhere database)

21. Topology Checker (Find topological errors in vector layers)

22. Zonal Statistics Plugin (Calculate count, sum, and mean of a raster for each polygon of a vector layer)

4.6.2 External Python Plugins

QGIS offers a growing number of external Python plugins that are provided by the community. These plugins reside in the official Plugins Repository and can be easily installed using the Python Plugin Installer. See Section

The Plugins Dialog .

4.7 Python Console

For scripting, it is possible to take advantage of an integrated Python console, which can be opened from menu:

Plugins

→ Python Console. The console opens as a non-modal utility window. For interaction with the QGIS environment, there is the qgis.utils.iface variable, which is an instance of QgsInterface. This interface allows access to the map canvas, menus, toolbars and other parts of the QGIS application.

For further information about working with the Python console and programming QGIS plugins and applications, please refer to http://www.qgis.org/html/en/docs/pyqgis_developer_cookbook/index.html

.

4.8 Known Issues

4.8.1 Number of open files limitation

If you are opening a large QGIS project and you are sure that all layers are valid, but some layers are flagged as bad, you are probably faced with this issue. Linux (and other OSs, likewise) has a limit of opened files by process.

Resource limits are per-process and inherited. The ulimit command, which is a shell built-in, changes the limits only for the current shell process; the new limit will be inherited by any child processes.

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You can see all current ulimit info by typing [email protected]:~$ ulimit -aS

You can see the current allowed number of opened files per proccess with the following command on a console [email protected]:~$ ulimit -Sn

To change the limits for an existing session, you may be able to use something like [email protected]:~$ ulimit -Sn #number_of_allowed_open_files [email protected]:~$ ulimit -Sn [email protected]:~$ qgis

To fix it forever

On most Linux systems, resource limits are set on login by the pam_limits module according to the settings contained in /etc/security/limits.conf or /etc/security/limits.d/*.conf. You should be able to edit those files if you have root privilege (also via sudo), but you will need to log in again before any changes take effect.

.

More info: http://www.cyberciti.biz/faq/linux-increase-the-maximum-number-of-open-files/ http://linuxaria.com/article/openfiles-in-linux?lang=en

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What’s new in QGIS 2.6

This release contains new features and extends the programmatic interface over previous versions. We recommend that you use this version over previous releases.

This release includes hundreds of bug fixes and many new features and enhancements that will be described in this manual. You may also review the visual changelog at http://changelog.linfiniti.com/qgis/version/2.6.0/ .

5.1 Application and Project Options

• Project filename in properties: You can now see the full path for the QGIS project file in the project properties dialog.

5.2 Data Providers

• DXF Export tool improvements:

– Tree view and attribute selection for layer assigment in dialog

– support fill polygons/HATCH

– represent texts as MTEXT instead of TEXT (including font, slant and weight)

– support for RGB colors when there’s no exact color match

– use AutoCAD 2000 DXF (R15) instead of R12

5.3 Map Composer

• Update map canvas extent from map composer extent: On the Item properties of a Map element there are now two extra buttons which allow you to (1) set the Map canvas extent according with the extent of your Map element and (2) view in Map canvas the extent currently set on your Map element.

• Multiple grid support: It is now possible to have more than one grid in your Map element. Each grid is fully customizable and can be assigned to a different CRS. This means, for example, you can now have a map layout with both geographic and projected grids.

• Selective export: To every item of your map composer layout, under Rendering options, you may exclude that object from map exports.

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5.4 QGIS Server

5.5 Symbology

.

5.6 User Interface

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6

Getting Started

This chapter gives a quick overview of installing QGIS, some sample data from the QGIS web page, and running a first and simple session visualizing raster and vector layers.

6.1 Asennus

Installation of QGIS is very simple. Standard installer packages are available for MS Windows and Mac OS X. For many flavors of GNU/Linux, binary packages (rpm and deb) or software repositories are provided to add to your installation manager. Get the latest information on binary packages at the QGIS website at http://download.qgis.org

.

6.1.1 Installation from source

If you need to build QGIS from source, please refer to the installation instructions. They are distributed with the QGIS source code in a file called INSTALL. You can also find them online at http://htmlpreview.github.io/?https://raw.github.com/qgis/QGIS/master/doc/INSTALL.html

6.1.2 Installation on external media

QGIS allows you to define a --configpath option that overrides the default path for user configuration (e.g.,

~/.qgis2

under Linux) and forces QSettings to use this directory, too. This allows you to, for instance, carry a

QGIS installation on a flash drive together with all plugins and settings. See section

System Menu

for additional information.

6.2 Sample Data

The user guide contains examples based on the QGIS sample dataset.

The Windows installer has an option to download the QGIS sample dataset. If checked, the data will be downloaded to your My Documents folder and placed in a folder called GIS Database. You may use Windows

Explorer to move this folder to any convenient location. If you did not select the checkbox to install the sample dataset during the initial QGIS installation, you may do one of the following:

• Use GIS data that you already have

• Download sample data from http://download.osgeo.org/qgis/data/qgis_sample_data.zip

• Uninstall QGIS and reinstall with the data download option checked (only recommended if the above solutions are unsuccessful)

For GNU/Linux and Mac OS X, there are not yet dataset installation packages available as rpm, deb or dmg. To use the sample dataset, download the file qgis_sample_data as a ZIP archive from http://download.osgeo.org/qgis/data/qgis_sample_data.zip

and unzip the archive on your system.

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The Alaska dataset includes all GIS data that are used for examples and screenshots in the user guide; it also includes a small GRASS database. The projection for the QGIS sample dataset is Alaska Albers Equal Area with units feet. The EPSG code is 2964.

PROJCS[ "Albers Equal Area" ,

GEOGCS[ "NAD27" ,

DATUM[ "North_American_Datum_1927" ,

SPHEROID[ "Clarke 1866" , 6378206.4

, 294.978698213898

,

AUTHORITY[ "EPSG" , "7008" ]],

TOWGS84[ 3 , 142 , 183 , 0 , 0 , 0 , 0 ],

AUTHORITY[ "EPSG" , "6267" ]],

PRIMEM[ "Greenwich" , 0 ,

AUTHORITY[ "EPSG" , "8901" ]],

UNIT[ "degree" , 0.0174532925199433

,

AUTHORITY[ "EPSG" , "9108" ]],

AUTHORITY[ "EPSG" , "4267" ]],

PROJECTION[ "Albers_Conic_Equal_Area" ],

PARAMETER[ "standard_parallel_1" , 55 ],

PARAMETER[ "standard_parallel_2" , 65 ],

PARAMETER[ "latitude_of_center" , 50 ],

PARAMETER[ "longitude_of_center" , 154 ],

PARAMETER[ "false_easting" , 0 ],

PARAMETER[ "false_northing" , 0 ],

UNIT[ "us_survey_feet" , 0.3048006096012192

]]

If you intend to use QGIS as a graphical front end for GRASS, you can find a selection of sample locations (e.g.,

Spearfish or South Dakota) at the official GRASS GIS website, http://grass.osgeo.org/download/sample-data/ .

6.3 Sample Session

Now that you have QGIS installed and a sample dataset available, we would like to demonstrate a short and simple QGIS sample session. We will visualize a raster and a vector layer. We will use the landcover raster layer, qgis_sample_data/raster/landcover.img, and the lakes vector layer, qgis_sample_data/gml/lakes.gml

.

6.3.1 Start QGIS

• Start QGIS by typing “QGIS” at a command prompt, or if using a precompiled binary, by using the

Applications menu.

• Start QGIS using the Start menu or desktop shortcut, or double click on a QGIS project file.

• Double click the icon in your Applications folder.

6.3.2 Load raster and vector layers from the sample dataset

1. Click on the

Load Raster icon.

2. Browse to the folder qgis_sample_data/raster/, select the ERDAS IMG file landcover.img

and click [Open].

3. If the file is not listed, check if the Files of type combo box at the bottom of the dialog is set on the right type, in this case “Erdas Imagine Images (*.img, *.IMG)”.

4. Now click on the

Load Vector icon.

5.

File should be selected as Source Type in the new Add vector layer dialog. Now click [Browse] to select the vector layer.

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6. Browse to the folder qgis_sample_data/gml/, select ‘Geography Markup Language [GML] [OGR]

(.gml,.GML)’ from the Files of type combo box, then select the GML file lakes.gml and click

[Open]. In the Add vector layer dialog, click [OK]. The Coordinate Reference System Selector dialog opens with NAD27 / Alaska Alberts selected, click [OK].

7. Zoom in a bit to your favorite area with some lakes.

8. Double click the lakes layer in the map legend to open the Properties dialog.

9. Click on the Style tab and select a blue as fill color.

10. Click on the Labels tab and check the Label this layer with checkbox to enable labeling. Choose the

“NAMES” field as the field containing labels.

11. To improve readability of labels, you can add a white buffer around them by clicking “Buffer” in the list on the left, checking Draw text buffer and choosing 3 as buffer size.

12. Click [Apply]. Check if the result looks good, and finally click [OK].

You can see how easy it is to visualize raster and vector layers in QGIS. Let’s move on to the sections that follow to learn more about the available functionality, features and settings, and how to use them.

6.4 Starting and Stopping QGIS

In section

Sample Session

you already learned how to start QGIS. We will repeat this here, and you will see that

QGIS also provides further command line options.

• Assuming that QGIS is installed in the PATH, you can start QGIS by typing qgis at a command prompt or by double clicking on the QGIS application link (or shortcut) on the desktop or in the Applications menu.

• Start QGIS using the Start menu or desktop shortcut, or double click on a QGIS project file.

• Double click the icon in your Applications folder. If you need to start QGIS in a shell, run

/path-to-installation-executable/Contents/MacOS/Qgis

.

To stop QGIS, click the menu option File QGIS

→ Quit, or use the shortcut Ctrl+Q.

6.5 Command Line Options

QGIS supports a number of options when started from the command line. To get a list of the options, enter qgis --help on the command line. The usage statement for QGIS is: qgis --help

QGIS - 2.6.0-Brighton ’Brighton’ (exported)

QGIS is a user friendly Open Source Geographic Information System.

Usage: /usr/bin/qgis.bin [OPTION] [FILE]

OPTION:

[--snapshot filename] emit snapshot of loaded datasets to given file

[--width width] width of snapshot to emit

[--height height] height of snapshot to emit

[--lang language] use language for interface text

[--project projectfile] load the given QGIS project

[--extent xmin,ymin,xmax,ymax] set initial map extent

[--nologo] hide splash screen

[--noplugins] don’t restore plugins on startup

[--nocustomization]

[--customizationfile]

[--optionspath path]

[--configpath path]

[--code path] don’t apply GUI customization use the given ini file as GUI customization use the given QSettings path use the given path for all user configuration run the given python file on load

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[--defaultui]

[--help] start by resetting user ui settings to default this text

FILE:

Files specified on the command line can include rasters, vectors, and QGIS project files (.qgs):

1. Rasters - supported formats include GeoTiff, DEM and others supported by GDAL

2. Vectors - supported formats include ESRI Shapefiles and others supported by OGR and PostgreSQL layers using the PostGIS extension

Vihje: Example Using command line arguments

You can start QGIS by specifying one or more data files on the command line. For example, assuming you are in the qgis_sample_data directory, you could start QGIS with a vector layer and a raster file set to load on startup using the following command: qgis ./raster/landcover.img ./gml/lakes.gml

Command line option --snapshot

This option allows you to create a snapshot in PNG format from the current view. This comes in handy when you have a lot of projects and want to generate snapshots from your data.

Currently, it generates a PNG file with 800x600 pixels. This can be adjusted using the --width and --height command line arguments. A filename can be added after --snapshot.

Command line option --lang

Based on your locale, QGIS selects the correct localization. If you would like to change your language, you can specify a language code. For example, --lang=it starts QGIS in italian localization. A list of currently supported languages with language code and status is provided at http://hub.qgis.org/wiki/quantumgis/GUI_Translation_Progress .

Command line option --project

Starting QGIS with an existing project file is also possible. Just add the command line option --project followed by your project name and QGIS will open with all layers in the given file loaded.

Command line option --extent

To start with a specific map extent use this option. You need to add the bounding box of your extent in the following order separated by a comma:

--extent xmin,ymin,xmax,ymax

Command line option --nologo

This command line argument hides the splash screen when you start QGIS.

Command line option --noplugins

If you have trouble at start-up with plugins, you can avoid loading them at start-up with this option. They will still be available from the Plugins Manager afterwards.

Command line option --customizationfile

Using this command line argument, you can define a GUI customization file, that will be used at startup.

Command line option --nocustomization

Using this command line argument, existing GUI customization will not be applied at startup.

Command line option --optionspath

You can have multiple configurations and decide which one to use when starting QGIS with this option. See

Options

to confirm where the operating system saves the settings files. Presently, there is no way to specify a file to write settings to; therefore, you can create a copy of the original settings file and rename it. The option specifies path to directory with settings. For example, to use /path/to/config/QGIS/QGIS2.ini settings file, use option:

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--optionspath /path/to/config/

Command line option --configpath

This option is similar to the one above, but furthermore overrides the default path for user configuration

(~/.qgis2) and forces QSettings to use this directory, too. This allows users to, for instance, carry a QGIS installation on a flash drive together with all plugins and settings.

Command line option --code

This option can be used to run a given python file directly after QGIS has started.

For example, when you have a python file named load_alaska.py with following content:

from qgis.utils

import

iface raster_file = "/home/gisadmin/Documents/qgis_sample_data/raster/landcover.img" layer_name = "Alaska" iface .

addRasterLayer(raster_file, layer_name)

Assuming you are in the directory where the file load_alaska.py is located, you can start QGIS, load the raster file landcover.img and give the layer the name ‘Alaska’ using the following command: qgis --code load_alaska.py

6.6 Projects

The state of your QGIS session is considered a project. QGIS works on one project at a time. Settings are considered as being either per-project or as a default for new projects (see section

Options ). QGIS can save the state of

your workspace into a project file using the menu options Project → Save or Project → Save As...

.

Load saved projects into a QGIS session using Project →

→ Open Recent →.

Open...

, Project → New from template or Project

If you wish to clear your session and start fresh, choose Project → New . Either of these menu options will prompt you to save the existing project if changes have been made since it was opened or last saved.

The kinds of information saved in a project file include:

• Layers added

• Layer properties, including symbolization

• Projection for the map view

• Last viewed extent

The project file is saved in XML format, so it is possible to edit the file outside QGIS if you know what you are doing. The file format has been updated several times compared with earlier QGIS versions. Project files from older QGIS versions may not work properly anymore. To be made aware of this, in the General tab under Settings

→ Options you can select:

• Prompt to save project and data source changes when required

• Warn when opening a project file saved with an older version of QGIS

Whenever you save a project in QGIS 2.2 now a backup of the project file is made.

6.7 Output

There are several ways to generate output from your QGIS session. We have discussed one already in section

Projects , saving as a project file. Here is a sampling of other ways to produce output files:

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.

• Menu option Project →

Save as Image opens a file dialog where you select the name, path and type of image

(PNG or JPG format). A world file with extension PNGW or JPGW saved in the same folder georeferences the image.

• Menu option Project → DXF Export ... opens a dialog where you can define the ‘Symbology mode’, the

‘Symbology scale’ and vector layers you want to export to DXF.

• Menu option Project → New Print Composer opens a dialog where you can lay out and print the current map canvas (see section

Print Composer ).

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7

QGIS GUI

When QGIS starts, you are presented with the GUI as shown in the figure (the numbers 1 through 5 in yellow circles are discussed below).

Kuva 7.1: QGIS GUI with Alaska sample data

Muista: Your window decorations (title bar, etc.) may appear different depending on your operating system and window manager.

The QGIS GUI is divided into five areas:

1. Menu Bar

2. Tool Bar

3. Map Legend

4. Map View

5. Status Bar

These five components of the QGIS interface are described in more detail in the following sections. Two more sections present keyboard shortcuts and context help.

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7.1 Menu Bar

The menu bar provides access to various QGIS features using a standard hierarchical menu. The top-level menus and a summary of some of the menu options are listed below, together with the associated icons as they appear on the toolbar, and keyboard shortcuts. The shortcuts presented in this section are the defaults; however, keyboard shortcuts can also be configured manually using the Configure shortcuts dialog, opened from Settings → Configure

Shortcuts...

.

Although most menu options have a corresponding tool and vice-versa, the menus are not organized exactly like the toolbars. The toolbar containing the tool is listed after each menu option as a checkbox entry. Some menu options only appear if the corresponding plugin is loaded. For more information about tools and toolbars, see section

Toolbar .

7.1.1 Project

Menu Option

New

Open

New from template

Open Recent

Save

Save As...

Save as Image...

DXF Export ...

Shortcut

Ctrl+N

Ctrl+O

Ctrl+S

Ctrl+Shift+S

New Print Composer

Ctrl+P

Composer manager ...

Print Composers

Exit QGIS

Ctrl+Q

Reference see

Projects

see

Projects

see

Projects

see

Projects

see

Projects

see see

Output

see

Output

see

Projects

Print Composer

Toolbar

Project

Project

Project

Project

Project

Project see

Print Composer

Project see

Print Composer

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7.1.2 Edit

Menu Option

Undo

Redo

Cut Features

Copy Features

Paste Features

Paste features as

Add Feature

Move Feature(s)

Delete Selected

Rotate Feature(s)

Simplify Feature

Add Ring

Add Part

Fill Ring

Delete Ring

Delete Part

Reshape Features

Offset Curves

Split Features

Split Parts

Merge Selected Features

Merge Attr. of Selected Features

Node Tool

Rotate Point Symbols

Shortcut Reference see

Advanced digitizing

Ctrl+Z

Ctrl+Shift+Z see

Advanced digitizing

Ctrl+X see

Digitizing an existing layer

Ctrl+C

Ctrl+V see

Digitizing an existing layer

see

Digitizing an existing layer

see

Working with the Attribute Table

Ctrl+.

see

Digitizing an existing layer

see

Digitizing an existing layer

see

Digitizing an existing layer

see

Advanced digitizing

Toolbar

Advanced Digitizing

Advanced Digitizing

Digitizing

Digitizing

Digitizing

Digitizing

Digitizing

Digitizing

Advanced Digitizing see

Advanced digitizing

Advanced Digitizing see

Advanced digitizing

see

Advanced digitizing

see

Advanced digitizing

see

Advanced digitizing

see

Advanced digitizing

see

Advanced digitizing

see

Advanced digitizing

see

Advanced digitizing

see

Advanced digitizing

see

Advanced digitizing

see

Advanced digitizing

see

Digitizing an existing layer

see

Advanced digitizing

Advanced Digitizing

Advanced Digitizing

Advanced Digitizing

Advanced Digitizing

Advanced Digitizing

Advanced Digitizing

Advanced Digitizing

Advanced Digitizing

Advanced Digitizing

Advanced Digitizing

Advanced Digitizing

Digitizing

Advanced Digitizing

After activating

Toggle editing mode for a layer, you will find the Add Feature icon in the Edit menu depending on the layer type (point, line or polygon).

7.1.3 Edit (extra)

Menu Option

Add Feature

Add Feature

Add Feature

Shortcut Reference Toolbar see

Digitizing an existing layer

Digitizing see

Digitizing an existing layer

Digitizing see

Digitizing an existing layer

Digitizing

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7.1.4 View

Menu Option

Pan Map

Pan Map to Selection

Zoom In

Zoom Out

Select

Identify Features

Measure

Zoom Full

Zoom To Layer

Zoom To Selection

Zoom Last

Zoom Next

Zoom Actual Size

Decorations

Map Tips

New Bookmark

Show Bookmarks

Refresh

Shortcut

Ctrl++

Ctrl+-

Ctrl+Shift+I

Ctrl+Shift+F

Ctrl+J

Ctrl+B see

Spatial Bookmarks

Ctrl+Shift+B see

Spatial Bookmarks

Ctrl+R

Reference Toolbar

Map Navigation

Map Navigation

Map Navigation

Map Navigation see

Select and deselect features

Attributes see

Measuring

Attributes

Attributes

Map Navigation

Map Navigation

Map Navigation

Map Navigation

Map Navigation

Map Navigation see

Decorations

Attributes

Attributes

Attributes

Map Navigation

7.1.5 Layer

Menu Option

New

Embed Layers and Groups ...

Add Vector Layer

Add Raster Layer

Add PostGIS Layer

Add SpatiaLite Layer

Add MSSQL Spatial Layer

Add Oracle GeoRaster Layer

Add SQL Anywhere Layer

Add WMS/WMTS Layer

Add WCS Layer

Add WFS Layer

Add Delimited Text Layer

Copy style

Paste style

Shortcut Reference see

Creating new Vector layers

see

Nesting Projects

Ctrl+Shift+V see

Työskentely vektoridatalla

Ctrl+Shift+R see

Loading raster data in QGIS

Ctrl+Shift+D see

PostGIS Layers

Ctrl+Shift+L see

SpatiaLite Layers

Toolbar

Manage Layers

Manage Layers

Manage Layers

Manage Layers

Manage Layers

Ctrl+Shift+M see

MSSQL Spatial Layers

Manage Layers see

Oracle Spatial GeoRaster Plugin

Manage Layers see

SQL Anywhere Plugin

Ctrl+Shift+W see

WMS/WMTS Client

see

WCS Client

Manage Layers

Manage Layers

Manage Layers see

WFS and WFS-T Client

see

Delimited Text Files

see

Style Menu

see

Style Menu

Manage Layers

Manage Layers

Continued on next page

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Menu Option

Open Attribute Table

Toggle Editing

Save Layer Edits

Current Edits

Save as...

Save selection as vector file...

Taulukko 7.1 – continued from previous page

Shortcut Reference Toolbar see

Working with the Attribute Table

Attributes see

Digitizing an existing layer

see

Digitizing an existing layer

see

Digitizing an existing layer

Digitizing

Digitizing

Digitizing

See

Working with the Attribute Table

Remove Layer(s)

Duplicate Layers (s)

Set CRS of Layer(s)

Set project CRS from Layer

Properties

Query...

Labeling

Add to Overview

Add All To Overview

Remove All From Overview

Show All Layers

Hide All Layers

Ctrl+D

Ctrl+Shift+C

Ctrl+Shift+O

Ctrl+Shift+U

Ctrl+Shift+H

Manage Layers

Manage Layers

Manage Layers

7.1.6 Settings

Menu Option

Panels

Toolbars

Shortcut

Toggle Full Screen Mode F 11

Reference see

Panels and Toolbars

see

Panels and Toolbars

Project Properties ...

Ctrl+Shift+P see

Projects

Custom CRS ...

Style Manager...

Configure shortcuts ...

Customization ...

Options ...

Snapping Options ...

see

Custom Coordinate Reference System

see

Presentation

see see

Customization

Options

Toolbar

7.1.7 Plugins

Menu Option Shortcut Reference

Manage and Install Plugins

Python Console see

The Plugins Dialog

When starting QGIS for the first time not all core plugins are loaded.

Toolbar

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7.1.8 Vector

Menu Option

Open Street Map

Analysis Tools

Research Tools

Geoprocessing Tools

Shortcut Reference see see see see

Loading OpenStreetMap Vectors

fTools Plugin fTools Plugin fTools Plugin

Geometry Tools

→ see

fTools Plugin

Data Management Tools

→ see

fTools Plugin

When starting QGIS for the first time not all core plugins are loaded.

Toolbar

7.1.9 Raster

Menu Option

Raster calculator ...

Shortcut Reference see

Raster Calculator

Toolbar

When starting QGIS for the first time not all core plugins are loaded.

7.1.10 Processing

Menu Option

Toolbox

Graphical Modeler

Shortcut Reference see

The toolbox

see

The graphical modeler

History and log

Options and configuration

Results viewer see

The history manager

see

Configuring the processing framework

see

Configuring external applications

Commander

Ctrl+Alt+M see

The QGIS Commander

When starting QGIS for the first time not all core plugins are loaded.

Toolbar

7.1.11 Help

Menu Option

Help Contents

What’s This?

API Documentation

Need commercial support?

QGIS Home Page

Check QGIS Version

About

QGIS Sponsors

Shortcut

F1

Shift+F1

Ctrl+H

Reference Toolbar

Help

Help

Please note that for Linux , the menu bar items listed above are the default ones in the KDE window manager.

In GNOME, the Settings menu has different content and its items have to be found here:

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Project Properties

Options

Configure Shortcuts

Style Manager

Project

Edit

Edit

Edit

Custom CRS

Panels

Toolbars

Edit

View

View

Toggle Full Screen Mode View

Tile scale slider

Live GPS tracking

View

View

7.2 Toolbar

The toolbar provides access to most of the same functions as the menus, plus additional tools for interacting with the map. Each toolbar item has pop-up help available. Hold your mouse over the item and a short description of the tool’s purpose will be displayed.

Every menu bar can be moved around according to your needs. Additionally, every menu bar can be switched off using your right mouse button context menu, holding the mouse over the toolbars (read also

Panels and Toolbars ).

Vihje: Restoring toolbars

If you have accidentally hidden all your toolbars, you can get them back by choosing menu option Settings →

Toolbars

→. If a toolbar disappears under Windows, which seems to be a problem in QGIS from time to time, you have to remove key \HKEY_CURRENT_USER\Software\QGIS\qgis\UI\state in the registry. When you restart QGIS, the key is written again with the default state, and all toolbars are visible again.

7.3 Map Legend

The map legend area lists all the layers in the project. The checkbox in each legend entry can be used to show or hide the layer. The Legend toolbar in the map legend are list allow you to Add group, Manage Layer Visibility of all layers or manage preset layers combination, Filter Legend by Map Content, Expand All or Collapse All and Remove Layer or Group. The button allows you to add Presets views in the legend. It means that you can choose to display some layer with specific categorization and add this view to the Presets list. To add a preset view just click on , choose Add Preset... from the drop down menu and give a name to the preset.

After that you will see a list with all the presets that you can recall pressing on the button.

All the added presets are also present in the map composer in order to allow you to create a map layout based on your specific views (see

Main properties ).

A layer can be selected and dragged up or down in the legend to change the Z-ordering. Z-ordering means that layers listed nearer the top of the legend are drawn over layers listed lower down in the legend.

Muista: This behaviour can be overridden by the ‘Layer order’ panel.

Layers in the legend window can be organised into groups. There are two ways to do this:

1. Press the icon to add a new group. Type in a name for the group and press Enter. Now click on an existing layer and drag it onto the group.

2. Select some layers, right click in the legend window and choose Group Selected. The selected layers will automatically be placed in a new group.

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To bring a layer out of a group, you can drag it out, or right click on it and choose Make to toplevel item. Groups can also be nested inside other groups.

The checkbox for a group will show or hide all the layers in the group with one click.

The content of the right mouse button context menu depends on whether the selected legend item is a raster or a vector layer. For GRASS vector layers,

Toggle editing is not available. See section

Digitizing and editing a GRASS vector layer

for information on editing GRASS vector layers.

Right mouse button menu for raster layers

• Zoom to layer extent

• Show in overview

• Zoom to Best Scale (100%)

• Stretch Using Current Extent

• Remove

• Duplicate

• Set Layer Scale Visibility

• Set Layer CRS

• Set Project CRS from Layer

• Save as ...

• Save As Layer Definition Style

• Properties

• Rename

• Copy Style

Additionally, according to layer position and selection

• Make to toplevel item

• Group Selected

Right mouse button menu for vector layers

• Zoom to Layer Extent

• Show in Overview

• Remove

• Duplicate

• Set Layer Scale Visibility

• Set Layer CRS

• Set Project CRS from Layer

• Open Attribute Table

• Toggle Editing (not available for GRASS layers)

• Save As ...

• Save As Layer Definition Style

• Filter

• Show Feature Count

• Properties

• Rename

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• Copy Style

Additionally, according to layer position and selection

• Make to toplevel item

• Group Selected

Right mouse button menu for layer groups

• Zoom to Group

• Remove

• Set Group CRS

• Rename

• Add Group

It is possible to select more than one layer or group at the same time by holding down the Ctrl key while selecting the layers with the left mouse button. You can then move all selected layers to a new group at the same time.

You may also delete more than one layer or group at once by selecting several layers with the Ctrl key and pressing Ctrl+D afterwards. This way, all selected layers or groups will be removed from the layers list.

7.3.1 Working with the Legend independent layer order

There is a panel that allows you to define an independent drawing order for the map legend. You can activate it in the menu Settings → Panels → Layer order. This feature allows you to, for instance, order your layers in order of importance, but still display them in the correct order (see

figure_layer_order ). Checking the

rendering order box underneath the list of layers will cause a revert to default behavior.

Control

7.3. Map Legend

Kuva 7.2: Define a legend independent layer order

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7.4 Map View

This is the “business end” of QGIS — maps are displayed in this area! The map displayed in this window will depend on the vector and raster layers you have chosen to load (see sections that follow for more information on how to load layers). The map view can be panned, shifting the focus of the map display to another region, and it can be zoomed in and out. Various other operations can be performed on the map as described in the toolbar description above. The map view and the legend are tightly bound to each other — the maps in view reflect changes you make in the legend area.

Vihje: Zooming the Map with the Mouse Wheel

You can use the mouse wheel to zoom in and out on the map. Place the mouse cursor inside the map area and roll the wheel forward (away from you) to zoom in and backwards (towards you) to zoom out. The zoom is centered on the mouse cursor position. You can customize the behavior of the mouse wheel zoom using the Map tools tab under the Settings → Options menu.

Vihje: Panning the Map with the Arrow Keys and Space Bar

You can use the arrow keys to pan the map. Place the mouse cursor inside the map area and click on the right arrow key to pan east, left arrow key to pan west, up arrow key to pan north and down arrow key to pan south. You can also pan the map using the space bar or the click on mouse wheel: just move the mouse while holding down space bar or click on mouse wheel.

7.5 Status Bar

.

The status bar shows you your current position in map coordinates (e.g., meters or decimal degrees) as the mouse pointer is moved across the map view. To the left of the coordinate display in the status bar is a small button that will toggle between showing coordinate position or the view extents of the map view as you pan and zoom in and out.

Next to the coordinate display you will find the scale display. It shows the scale of the map view. If you zoom in or out, QGIS shows you the current scale. There is a scale selector, which allows you to choose between predefined scales from 1:500 to 1:1000000.

A progress bar in the status bar shows the progress of rendering as each layer is drawn to the map view. In some cases, such as the gathering of statistics in raster layers, the progress bar will be used to show the status of lengthy operations.

If a new plugin or a plugin update is available, you will see a message at the far left of the status bar. On the right side of the status bar, there is a small checkbox which can be used to temporarily prevent layers being rendered to the map view (see section

Rendering

below). The icon immediately stops the current map rendering process.

To the right of the render functions, you find the EPSG code of the current project CRS and a projector icon.

Clicking on this opens the projection properties for the current project.

Vihje: Calculating the Correct Scale of Your Map Canvas

When you start QGIS, the default units are degrees, and this means that QGIS will interpret any coordinate in your layer as specified in degrees. To get correct scale values, you can either change this setting to meters manually in the General tab under Settings → Project Properties, or you can select a project CRS clicking on the

CRS status icon in the lower right-hand corner of the status bar. In the last case, the units are set to what the project projection specifies (e.g., ‘+units=m’).

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LUKU

8

General Tools

8.1 Keyboard shortcuts

QGIS provides default keyboard shortcuts for many features. You can find them in section

Menu Bar . Additionally,

the menu option Settings → Configure Shortcuts.. allows you to change the default keyboard shortcuts and to add new keyboard shortcuts to QGIS features.

Kuva 8.1: Define shortcut options (Gnome)

Configuration is very simple. Just select a feature from the list and click on [Change], [Set none] or [Set default].

Once you have finished your configuration, you can save it as an XML file and load it to another QGIS installation.

8.2 Context help

When you need help on a specific topic, you can access context help via the [Help] button available in most dialogs

— please note that third-party plugins can point to dedicated web pages.

8.3 Rendering

By default, QGIS renders all visible layers whenever the map canvas is refreshed. The events that trigger a refresh of the map canvas include:

• Adding a layer

• Panning or zooming

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• Resizing the QGIS window

• Changing the visibility of a layer or layers

QGIS allows you to control the rendering process in a number of ways.

8.3.1 Scale Dependent Rendering

Scale-dependent rendering allows you to specify the minimum and maximum scales at which a layer will be visible. To set scale-dependent rendering, open the Properties dialog by double-clicking on the layer in the legend.

On the General tab, click on the minimum and maximum scale values.

Scale dependent visibility checkbox to activate the feature, then set the

You can determine the scale values by first zooming to the level you want to use and noting the scale value in the

QGIS status bar.

8.3.2 Controlling Map Rendering

Map rendering can be controlled in the various ways, as described below.

Suspending Rendering

To suspend rendering, click the Render checkbox in the lower right corner of the status bar. When the

Render checkbox is not checked, QGIS does not redraw the canvas in response to any of the events described in section

Rendering . Examples of when you might want to suspend rendering include:

• Adding many layers and symbolizing them prior to drawing

• Adding one or more large layers and setting scale dependency before drawing

• Adding one or more large layers and zooming to a specific view before drawing

• Any combination of the above

Checking the

Render checkbox enables rendering and causes an immediate refresh of the map canvas.

Setting Layer Add Option

You can set an option to always load new layers without drawing them. This means the layer will be added to the map, but its visibility checkbox in the legend will be unchecked by default. To set this option, choose menu option Settings → Options and click on the Rendering tab. Uncheck the By default new layers added to the map should be displayed checkbox. Any layer subsequently added to the map will be off (invisible) by default.

Stopping Rendering

To stop the map drawing, press the ESC key. This will halt the refresh of the map canvas and leave the map partially drawn. It may take a bit of time between pressing ESC and the time the map drawing is halted.

Muista: It is currently not possible to stop rendering — this was disabled in the Qt4 port because of User Interface

(UI) problems and crashes.

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Updating the Map Display During Rendering

You can set an option to update the map display as features are drawn. By default, QGIS does not display any features for a layer until the entire layer has been rendered. To update the display as features are read from the datastore, choose menu option Settings → Options and click on the Rendering tab. Set the feature count to an appropriate value to update the display during rendering. Setting a value of 0 disables update during drawing (this is the default). Setting a value too low will result in poor performance, as the map canvas is continually updated during the reading of the features. A suggested value to start with is 500.

Influence Rendering Quality

To influence the rendering quality of the map, you have two options. Choose menu option Settings → Options, click on the Rendering tab and select or deselect following checkboxes:

Make lines appear less jagged at the expense of some drawing performance

Fix problems with incorrectly filled polygons

Speed-up rendering

There are two settings that allow you to improve rendering speed. Open the QGIS options dialog using Settings

→ Options, go to the Rendering tab and select or deselect the following checkboxes:

• Enable back buffer . This provides better graphics performance at the cost of losing the possibility to cancel rendering and incrementally draw features. If it is unchecked, you can set the Number of features to draw before updating the display , otherwise this option is inactive.

• Use render caching where possible to speed up redraws

8.4 Measuring

Measuring works within projected coordinate systems (e.g., UTM) and unprojected data. If the loaded map is defined with a geographic coordinate system (latitude/longitude), the results from line or area measurements will be incorrect. To fix this, you need to set an appropriate map coordinate system (see section

Working with Projections

).

All measuring modules also use the snapping settings from the digitizing module. This is useful, if you want to measure along lines or areas in vector layers.

To select a measuring tool, click on and select the tool you want to use.

8.4.1 Measure length, areas and angles

Measure Line

: QGIS is able to measure real distances between given points according to a defined ellipsoid. To configure this, choose menu option Settings → Options, click on the Map tools tab and select the appropriate ellipsoid. There, you can also define a rubberband color and your preferred measurement units (meters or feet) and angle units (degrees, radians and gon). The tool then allows you to click points on the map. Each segment length, as well as the total, shows up in the measure window. To stop measuring, click your right mouse button.

Measure Area

: Areas can also be measured. In the measure window, the accumulated area size appears. In addition, the measuring tool will snap to the currently selected layer, provided that layer has its snapping tolerance set (see section

Setting the Snapping Tolerance and Search Radius ). So, if you want to measure exactly along a line feature,

or around a polygon feature, first set its snapping tolerance, then select the layer. Now, when using the measuring tools, each mouse click (within the tolerance setting) will snap to that layer.

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Kuva 8.2: Measure Distance (Gnome)

Kuva 8.3: Measure Area (Gnome)

Measure Angle

: You can also measure angles. The cursor becomes cross-shaped. Click to draw the first segment of the angle you wish to measure, then move the cursor to draw the desired angle. The measure is displayed in a pop-up dialog.

Kuva 8.4: Measure Angle (Gnome)

8.4.2 Select and deselect features

The QGIS toolbar provides several tools to select features in the map canvas. To select one or several features, just click on and select your tool:

Select Single Feature

Select Features by Rectangle

Select Features by Polygon

Select Features by Freehand

Select Features by Radius

To deselect all selected features click on

Deselect features from all layers

.

Select feature using an expression allow user to select feature using expression dialog. See

Expressions

chapter for some example.

Users can save features selection into a New Memory Vector Layer or a New Vector Layer using Edit → Paste

Feature as ...

and choose the mode you want.

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8.5 Identify features

The Identify tool allows you to interact with the map canvas and get information on features in a pop-up window.

Identify features

To identify features, use View → Identify features or press Ctrl + Shift + I, or click on the icon in the toolbar.

If you click on several features, the Identify results dialog will list information about all the selected features. The first item is the number of the feature in the list of results, followed by the layer name. Then, its first child will be the name of a field with its value. Finally, all information about the feature is displayed.

This window can be customized to display custom fields, but by default it will display three kinds of information:

• Actions: Actions can be added to the identify feature windows. When clicking on the action label, action will be run. By default, only one action is added, to view feature form for editing.

• Derived: This information is calculated or derived from other information. You can find clicked coordinate,

X and Y coordinates, area in map units and perimeter in map units for polygons, length in map units for lines and feature ids.

• Data attributes: This is the list of attribute fields from the data.

Kuva 8.5: Identify feaures dialog (Gnome)

At the bottom of the window, you have five icons:

Expand tree

Collapse tree

Default behaviour

Copy attributes

Print selected HTML response

Other functions can be found in the context menu of the identified item. For example, from the context menu you can:

• View the feature form

• Zoom to feature

• Copy feature: Copy all feature geometry and attributes

• Toggle feature selection: adds identified feature to selection

• Copy attribute value: Copy only the value of the attribute that you click on

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• Copy feature attributes: Copy only attributes

• Clear result: Remove results in the window

• Clear highlights: Remove features highlighted on the map

• Highlight all

• Highlight layer

• Activate layer: Choose a layer to be activated

• Layer properties: Open layer properties window

• Expand all

• Collapse all

8.6 Decorations

The Decorations of QGIS include the Grid, the Copyright Label, the North Arrow and the Scale Bar. They are used to ‘decorate’ the map by adding cartographic elements.

8.6.1 Grid

Grid allows you to add a coordinate grid and coordinate annotations to the map canvas.

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Kuva 8.6: The Grid Dialog

1. Select from menu View → Decorations → Grid. The dialog starts (see

figure_decorations_1 ).

2. Activate the canvas.

Enable grid checkbox and set grid definitions according to the layers loaded in the map

3. Activate the Draw annotations checkbox and set annotation definitions according to the layers loaded in the map canvas.

4. Click [Apply] to verify that it looks as expected.

5. Click [OK] to close the dialog.

Luku 8. General Tools

8.6.2 Copyright Label

Copyright label adds a copyright label using the text you prefer to the map.

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Kuva 8.7: The Copyright Dialog

1. Select from menu View → Decorations → Copyright Label. The dialog starts (see

figure_decorations_2 ).

2. Enter the text you want to place on the map. You can use HTML as shown in the example.

3. Choose the placement of the label from the Placement combo box.

4. Make sure the Enable Copyright Label checkbox is checked.

5. Click [OK].

In the example above, which is the default, QGIS places a copyright symbol followed by the date in the lower right-hand corner of the map canvas.

8.6.3 North Arrow

North Arrow places a simple north arrow on the map canvas. At present, there is only one style available. You can adjust the angle of the arrow or let QGIS set the direction automatically. If you choose to let QGIS determine the direction, it makes its best guess as to how the arrow should be oriented. For placement of the arrow, you have four options, corresponding to the four corners of the map canvas.

Kuva 8.8: The North Arrow Dialog

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8.6.4 Scale Bar

Scale Bar adds a simple scale bar to the map canvas. You can control the style and placement, as well as the labeling of the bar.

Kuva 8.9: The Scale Bar Dialog

QGIS only supports displaying the scale in the same units as your map frame. So if the units of your layers are in meters, you can’t create a scale bar in feet. Likewise, if you are using decimal degrees, you can’t create a scale bar to display distance in meters.

To add a scale bar:

1. Select from menu View → Decorations → Scale Bar. The dialog starts (see

figure_decorations_4 ).

2. Choose the placement from the Placement

3. Choose the style from the Scale bar style combo box.

combo box.

4. Select the color for the bar Color of bar

5. Set the size of the bar and its label Size of bar .

or use the default black color.

6. Make sure the

7. Optionally, check

8. Click [OK].

Enable scale bar checkbox is checked.

Automatically snap to round number on resize .

Vihje: Settings of Decorations

When you save a .qgs project, any changes you have made to Grid, North Arrow, Scale Bar and Copyright will be saved in the project and restored the next time you load the project.

8.7 Annotation Tools

The

Text Annotation tool in the attribute toolbar provides the possibility to place formatted text in a balloon on the

QGIS map canvas. Use the Text Annotation tool and click into the map canvas.

Double clicking on the item opens a dialog with various options. There is the text editor to enter the formatted text and other item settings. For instance, there is the choice of having the item placed on a map position (displayed by a marker symbol) or to have the item on a screen position (not related to the map). The item can be moved by map position (by dragging the map marker) or by moving only the balloon. The icons are part of the GIS theme, and they are used by default in the other themes, too.

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Kuva 8.10: Annotation text dialog

The

Move Annotation tool allows you to move the annotation on the map canvas.

8.7.1 Html annotations

The

Html Annotation tools in the attribute toolbar provides the possibility to place the content of an html file in a balloon on the QGIS map canvas. Using the Html Annotation tool, click into the map canvas and add the path to the html file into the dialog.

8.7.2 SVG annotations

The

SVG Annotation tool in the attribute toolbar provides the possibility to place an SVG symbol in a balloon on the QGIS map canvas. Using the SVG Annotation tool, click into the map canvas and add the path to the SVG file into the dialog.

8.7.3 Form annotations

Additionally, you can also create your own annotation forms. The

Form Annotation tool is useful to display attributes of a vector layer in a customized Qt Designer form (see

figure_custom_annotation ). This is similar

to the designer forms for the Identify features tool, but displayed in an annotation item. Also see this video https://www.youtube.com/watch?v=0pDBuSbQ02o from Tim Sutton for more information.

Muista: If you press Ctrl+T while an Annotation tool is active (move annotation, text annotation, form annotation), the visibility states of the items are inverted.

8.8 Spatial Bookmarks

Spatial Bookmarks allow you to “bookmark” a geographic location and return to it later.

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Kuva 8.11: Customized qt designer annotation form

8.8.1 Creating a Bookmark

To create a bookmark:

1. Zoom or pan to the area of interest.

2. Select the menu option View → New Bookmark or press Ctrl-B.

3. Enter a descriptive name for the bookmark (up to 255 characters).

4. Press Enter to add the bookmark or [Delete] to remove the bookmark.

Note that you can have multiple bookmarks with the same name.

8.8.2 Working with Bookmarks

To use or manage bookmarks, select the menu option View → Show Bookmarks. The Geospatial Bookmarks dialog allows you to zoom to or delete a bookmark. You cannot edit the bookmark name or coordinates.

8.8.3 Zooming to a Bookmark

From the Geospatial Bookmarks dialog, select the desired bookmark by clicking on it, then click [Zoom To]. You can also zoom to a bookmark by double-clicking on it.

8.8.4 Deleting a Bookmark

To delete a bookmark from the Geospatial Bookmarks dialog, click on it, then click [Delete]. Confirm your choice by clicking [Yes], or cancel the delete by clicking [No].

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8.9 Nesting Projects

If you want to embed content from other project files into your project, you can choose Layer → Embed Layers and Groups .

8.9.1 Embedding layers

The following dialog allows you to embed layers from other projects. Here is a small example:

1. Press to look for another project from the Alaska dataset.

2. Select the project file grassland. You can see the content of the project (see

figure_embed_dialog ).

3. Press Ctrl and click on the layers grassland and regions. Press [OK]. The selected layers are embedded in the map legend and the map view now.

Kuva 8.12: Select layers and groups to embed

While the embedded layers are editable, you can’t change their properties like style and labeling.

8.9.2 Removing embedded layers

.

Right-click on the embedded layer and choose

Remove

.

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QGIS Configuration

QGIS is highly configurable through the Settings menu. Choose between Panels, Toolbars, Project Properties,

Options and Customization.

Muista: QGIS follows desktop guidelines for the location of options and project properties item. Consequently related to the OS you are using, location of some of items described above could be located in the :menuselection‘view‘ menu (Panels and Toolbars) or in Project for Options.

9.1 Panels and Toolbars

In the Panels→ menu, you can switch on and off QGIS widgets. The Toolbars→ menu provides the possibility to switch on and off icon groups in the QGIS toolbar (see

figure_panels_toolbars ).

Kuva 9.1: The Panels and Toolbars menu

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In QGIS, you can use an overview panel that provides a full extent view of layers added to it. It can be selected under the menu Settings

→ Panels or

View

→ Panels. Within the view is a rectangle showing the current map extent. This allows you to quickly determine which area of the map you are currently viewing. Note that labels are not rendered to the map overview even if the layers in the map overview have been set up for labeling.

If you click and drag the red rectangle in the overview that shows your current extent, the main map view will update accordingly.

Vihje: Show Log Messages

It’s possible to track the QGIS messages. You can activate Log Messages in the menu Settings

→ Panels or

View

→ Panels and follow the messages that appear in the different tabs during loading and operation.

9.2 Project Properties

In the properties window for the project under Settings

→ Project Properties (kde) or

Properties (Gnome), you can set project-specific options. These include:

Project

→ Project

• In the General menu, the project title, selection and background color, layer units, precision, and the option to save relative paths to layers can be defined. If the CRS transformation is on, you can choose an ellipsoid for distance calculations. You can define the canvas units (only used when CRS transformation is disabled) and the precision of decimal places to use. You can also define a project scale list, which overrides the global predefined scales.

• The CRS menu enables you to choose the Coordinate Reference System for this project, and to enable on-the-fly re-projection of raster and vector layers when displaying layers from a different CRS.

• With the third Identify layers menu, you set (or disable) which layers will respond to the identify tool (see the “Map tools” paragraph from the

Options

section to enable identifying of multiple layers).

• The Default Styles menu lets you control how new layers will be drawn when they do not have an existing

.qml

style defined. You can also set the default transparency level for new layers and whether symbols should have random colours assigned to them. There is also an additional section where you can define specific colors for the running project. You can find the added colors in the drop down menu of the color dialog window present in each renderer.

• The tab OWS Server allows you to define information about the QGIS Server WMS and WFS capabilities, extent and CRS restrictions.

• The Macros menu is used to edit Python macros for projects. Currently, only three macros are available: openProject()

, saveProject() and closeProject().

• The Relations menu is used to define 1:n relations. The relations are defined in the project properties dialog.

Once relations exist for a layer, a new user interface element in the form view (e.g. when identifying a feature and opening its form) will list the related entities. This provides a powerful way to express e.g. the inspection history on a length of pipeline or road segment. You can find out more about 1:n relations support in Section

Creating one to many relations .

9.3 Options

Some basic options for QGIS can be selected using the Options dialog. Select the menu option Settings →

Options . The tabs where you can customize your options are described below.

9.3.1 General Menu

Application

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Kuva 9.2: Macro settings in QGIS

• Select the Style (QGIS restart required)

‘Plastique’ and ‘Cleanlooks’ ( ).

• Define the Icon theme and choose between ‘Oxygen’,’Windows’,’Motif’,’CDE’,

. Currently only ‘default’ is possible.

• Define the Icon size .

• Define the Font. Choose between Qt default and a user-defined font.

• Change the Timeout for timed messages or dialogs .

Hide splash screen at startup

Show tips at startup

Bold group box titles

QGIS-styled group boxes

• Use live-updating color chooser dialog

Project files

• Open project on launch cific’ use the

(choose between ‘New’, ‘Most recent’ and ‘Specific’). When choosing ‘Speto define a project.

• Create new project from default project . You have the possibility to press on Set current project as default or on Reset default. You can browse through your files and define a directory where you find your user-defined project templates. This will be added to Project → New From Template. If you first activate

Create new project from default project and then save a project in the project templates folder.

• Prompt to save project and data source changes when required

• Warn when opening a project file saved with an older version of QGIS

• Enable macros . This option was created to handle macros that are written to perform an action on project events. You can choose between ‘Never’, ‘Ask’, ‘For this session only’ and ‘Always (not recommended)’.

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9.3.2 System Menu

Environment

System environment variables can now be viewed, and many configured, in the Environment group (see

figure_environment_variables ). This is useful for platforms, such as Mac, where a GUI application does not neces-

sarily inherit the user’s shell environment. It’s also useful for setting and viewing environment variables for the external tool sets controlled by the Processing toolbox (e.g., SAGA, GRASS), and for turning on debugging output for specific sections of the source code.

• Use custom variables (restart required - include separators) . You can [Add] and [Remove] variables.

Already-defined environment variables are displayed in Current environment variables, and it’s possible to filter them by activating Show only QGIS-specific variables .

Kuva 9.3: System environment variables in QGIS

Plugin paths

[Add] or [Remove] Path(s) to search for additional C++ plugin libraries

9.3.3 Data Sources Menu

Feature attributes and table

Open attribute table in a dock window (QGIS restart required)

• Copy geometry in WKT representation from attribute table . When using

Copy selected rows to clipboard from the Attribute table dialog, this has the result that the coordinates of points or vertices are also copied to the clipboard.

• Attribute table behaviour . There are three possibilities: ‘Show all features’, ‘Show selected features’ and ‘Show features visible on map’.

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• Attribute table row cache . This row cache makes it possible to save the last loaded N attribute rows so that working with the attribute table will be quicker. The cache will be deleted when closing the attribute table.

• Representation for NULL values. Here, you can define a value for data fields containing a NULL value.

Data source handling

• Scan for valid items in the browser dock contents’.

. You can choose between ‘Check extension’ and ‘Check file

• Scan for contents of compressed files (.zip) in browser dock possible.

. ‘No’, ‘Basic scan’ and ‘Full scan’ are

• Prompt for raster sublayers when opening. Some rasters support sublayers — they are called subdatasets in GDAL. An example is netCDF files — if there are many netCDF variables, GDAL sees every variable as a subdataset. The option allows you to control how to deal with sublayers when a file with sublayers is opened. You have the following choices:

– ‘Always’: Always ask (if there are existing sublayers)

– ‘If needed’: Ask if layer has no bands, but has sublayers

– ‘Never’: Never prompt, will not load anything

– ‘Load all’: Never prompt, but load all sublayers

• Ignore shapefile encoding declaration . If a shapefile has encoding information, this will be ignored by

QGIS.

• Add PostGIS layer with double click and select in extended mode

• Add Oracle layers with double click and select in extended mode

9.3.4 Rendering Menu

Rendering behaviour

By default new layers added to the map should be displayed

Use render caching where possible to speed up redraws

Render layers in parallel using many CPU cores

• Max cores to use

• Map update interval (default to 250 ms)

• Enable feature simplication by default for newly added layers

• Simplification threshold

• Simplify on provider side if possible

• Maximum scale at which the layer should be simplified

Rendering quality

Rasters

Make lines appear less jagged at the expense of some drawing performance

• With RGB band selection, you can define the number for the Red, Green and Blue band.

Contrast enhancement

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• Single band gray . A single band gray can have ‘No stretch’, ‘Stretch to MinMax’, ‘Stretch and Clip to MinMax’ and also ‘Clip to MinMax’.

• Multi band color (byte/band)

MinMax’ and ‘Clip to MinMax’.

. Options are ‘No stretch’, ‘Stretch to MinMax’, ‘Stretch and Clip to

• Multi band color (>byte/band)

MinMax’ and ‘Clip to MinMax’.

• Limits (minimum/maximum)

‘Mean +/- standard deviation’.

• Cumulative pixel count cut limits

• Standard deviation multiplier

Debugging

. Options are ‘No stretch’, ‘Stretch to MinMax’, ‘Stretch and Clip to

. Options are ‘Cumulative pixel count cut’, ‘Minimum/Maximum’,

• Map canvas refresh

9.3.5 Colors Menu

This menu allows you to add some custom color that you can find in each color dialog window of the renderes.

You will see a set of predefined colors in the tab: you can delete or edit all of them. Moreover you can add the color you want and perform some copy and paste operation. Finally you can export the color set as a gpl file or import them.

9.3.6 Canvas and Legend Menu

Default map appearance (overridden by project properties)

• Define a Selection color and a Background color.

Layer legend

• Double click action in legend the double click.

. You can either ‘Open layer properties’ or ‘Open attribute table’ with

• The following Legend item styles are possible:

Capitalise layer names

Bold layer names

Bold group names

Display classification attribute names

Create raster icons (may be slow)

Add new layers to selected or current group

9.3.7 Map tools Menu

This menu offers some options regarding the behaviour of the Identify tool.

• Search radius for identifying and displaying map tips is a tolerance factor expressed as a percentage of the map width. This means the identify tool will depict results as long as you click within this tolerance.

• Highlight color allows you to choose with which color should features being identified are to be highlighted.

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• Buffer expressed as a percentage of the map width, determines a buffer distance to be rendered from the outline of the identify highlight.

• Minimum width expressed as a percentage of the map width, determines how thick should the outline of a highlighted object be.

Measure tool

• Define Rubberband color for measure tools

• Define Decimal places

• Keep base unit

• Preferred measurements units (‘Meters’, ‘Feet’, ‘Nautical Miles’ or ‘Degrees’)‘

• Preferred angle units (‘Degrees’, ‘Radians’ or ‘Gon’)

Panning and zooming

• Define Mouse wheel action (‘Zoom’, ‘Zoom and recenter’, ‘Zoom to mouse cursor’, ‘Nothing’)

• Define Zoom factor for wheel mouse

Predefined scales

Here, you find a list of predefined scales. With the [+] and [-] buttons you can add or remove your individual scales.

9.3.8 Composer Menu

Composition defaults

You can define the Default font here.

Grid appearance

• Define the Grid style

• Define the Color...

Grid defaults

• Define the Spacing

• Define the Grid offset

• Define the Snap tolerance

Guide defaults

• Define the Snap tolerance

(‘Solid’, ‘Dots’, ‘Crosses’) for x and y

9.3.9 Digitizing Menu

Feature creation

• Suppress attributes pop-up windows after each created feature

• Reuse last entered attribute values

• Validate geometries. Editing complex lines and polygons with many nodes can result in very slow rendering.

This is because the default validation procedures in QGIS can take a lot of time. To speed up rendering, it is possible to select GEOS geometry validation (starting from GEOS 3.3) or to switch it off. GEOS geometry validation is much faster, but the disadvantage is that only the first geometry problem will be reported.

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• Define Rubberband Line width and Line color

Snapping

• Open snapping options in a dock window (QGIS restart required)

• Define Default snap mode (‘To vertex’, ‘To segment’, ‘To vertex and segment’, ‘Off’)

• Define Default snapping tolerance in map units or pixels

• Define the Search radius for vertex edits in map units or pixels

Vertex markers

• Show markers only for selected features

• Define vertex Marker style

• Define vertex Marker size

Curve offset tool

(‘Cross’ (default), ‘Semi transparent circle’ or ‘None’)

The next 3 options refer to the

Offset Curve tool in

Advanced digitizing . Through the various settings, it is possible

to influence the shape of the line offset. These options are possible starting from GEOS 3.3.

• Join style

• Quadrant segments

• Miter limit

9.3.10 GDAL Menu

GDAL is a data exchange library for raster files. In this tab, you can Edit create options and Edit Pyramids Options of the raster formats. Define which GDAL driver is to be used for a raster format, as in some cases more than one

GDAL driver is available.

9.3.11 CRS Menu

Default CRS for new projects

Don’t enable ‘on the fly’ reprojection

Automatically enable ‘on the fly’ reprojection if layers have different CRS

• Enable ‘on the fly’ reprojection by default

• Select a CRS and Always start new projects with this CRS

CRS for new layers

This area allows you to define the action to take when a new layer is created, or when a layer without a CRS is loaded.

• Prompt for CRS

• Use project CRS

• Use default CRS displayed below

Default datum transformations

• Ask for datum transformation when no default is defined

• If you have worked with the ‘on-the-fly’ CRS transformation you can see the result of the transformation in the window below. You can find information about ‘Source CRS’ and ‘Destination CRS’ as well as ‘Source datum transform’ and ‘Destination datum transform’.

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9.3.12 Locale Menu

• Overwrite system locale and Locale to use instead

• Information about active system locale

9.3.13 Network Menu

General

• Define WMS search address, default is http://geopole.org/wms/search?search=\%1\&type=rss

• Define Timeout for network requests (ms) - default is 60000

• Define Default expiration period for WMSC/WMTS tiles (hours) - default is 24

• Define Max retry in case of tile request errors

• Define User-Agent

Kuva 9.4: Proxy-settings in QGIS

Cache settings

Define the Directory and a Size for the cache.

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• Use proxy for web access and define ‘Host’, ‘Port’, ‘User’, and ‘Password’.

• Set the Proxy type according to your needs.

– Default Proxy: Proxy is determined based on the application proxy set using

– Socks5Proxy: Generic proxy for any kind of connection. Supports TCP, UDP, binding to a port (incoming connections) and authentication.

– HttpProxy: Implemented using the “CONNECT” command, supports only outgoing TCP connections; supports authentication.

– HttpCachingProxy: Implemented using normal HTTP commands, it is useful only in the context of

HTTP requests.

– FtpCachingProxy: Implemented using an FTP proxy, it is useful only in the context of FTP requests.

Excluding some URLs can be added to the text box below the proxy settings (see

Figure_Network_Tab ).

If you need more detailed information about the different proxy settings, please refer to the manual of the underlying QT library documentation at http://doc.trolltech.com/4.5/qnetworkproxy.html#ProxyType-enum .

Vihje: Using Proxies

Using proxies can sometimes be tricky. It is useful to proceed by ‘trial and error’ with the above proxy types, to check to see if they succeed in your case.

You can modify the options according to your needs. Some of the changes may require a restart of QGIS before they will be effective.

• Settings are saved in a text file: $HOME/.config/QGIS/QGIS2.conf

• You can find your settings in: $HOME/Library/Preferences/org.qgis.qgis.plist

• Settings are stored in the registry under: HKEY\CURRENT_USER\Software\QGIS\qgis

9.4 Customization

The customization tool lets you (de)activate almost every element in the QGIS user interface. This can be very useful if you have a lot of plugins installed that you never use and that are filling your screen.

Kuva 9.5: The Customization dialog

QGIS Customization is divided into five groups. In Menus , you can hide entries in the Menu bar. In Panel , you find the panel windows. Panel windows are applications that can be started and used as a floating, top-level window or embedded to the QGIS main window as a docked widget (see also

Panels and Toolbars ). In the

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Status Bar , features like the coordinate information can be deactivated. In toolbar icons of QGIS, and in

Widgets

Toolbars , you can (de)activate the

, you can (de)activate dialogs as well as their buttons.

.

With

Switch to catching widgets in main application

, you can click on elements in QGIS that you want to be hidden and find the corresponding entry in Customization (see

figure_customization ). You can also save your various setups

for different use cases as well. Before your changes are applied, you need to restart QGIS.

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10

Working with Projections

QGIS allows users to define a global and project-wide CRS (coordinate reference system) for layers without a pre-defined CRS. It also allows the user to define custom coordinate reference systems and supports on-the-fly

(OTF) projection of vector and raster layers. All of these features allow the user to display layers with different

CRSs and have them overlay properly.

10.1 Overview of Projection Support

QGIS has support for approximately 2,700 known CRSs. Definitions for each CRS are stored in a SQLite database that is installed with QGIS. Normally, you do not need to manipulate the database directly. In fact, doing so may cause projection support to fail. Custom CRSs are stored in a user database. See section

Custom Coordinate

Reference System

for information on managing your custom coordinate reference systems.

The CRSs available in QGIS are based on those defined by the European Petroleum Search Group (EPSG) and the Institut Geographique National de France (IGNF) and are largely abstracted from the spatial reference tables used in GDAL. EPSG identifiers are present in the database and can be used to specify a CRS in QGIS.

In order to use OTF projection, either your data must contain information about its coordinate reference system or you will need to define a global, layer or project-wide CRS. For PostGIS layers, QGIS uses the spatial reference identifier that was specified when the layer was created. For data supported by OGR, QGIS relies on the presence of a recognized means of specifying the CRS. In the case of shapefiles, this means a file containing the wellknown text (WKT) specification of the CRS. This projection file has the same base name as the shapefile and a .prj extension. For example, a shapefile named alaska.shp would have a corresponding projection file named alaska.prj.

Whenever you select a new CRS, the layer units will automatically be changed in the General tab of the Project

Properties dialog under the Project (Gnome, OS X) or Settings (KDE, Windows) menu.

10.2 Global Projection Specification

QGIS starts each new project using the global default projection. The global default CRS is EPSG:4326 - WGS 84

(proj=longlat +ellps=WGS84 +datum=WGS84 +no_defs), and it comes predefined in QGIS. This default can be changed via the [Select...] button in the first section, which is used to define the default coordinate reference system for new projects, as shown in

figure_projection_1 . This choice will be saved for use in subsequent

QGIS sessions.

When you use layers that do not have a CRS, you need to define how QGIS responds to these layers. This can be done globally or project-wide in the CRS tab under Settings → Options .

The options shown in

figure_projection_1

are:

Prompt for CRS

Use project CRS

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• Use default CRS displayed below

If you want to define the coordinate reference system for a certain layer without CRS information, you can also do that in the General tab of the raster and vector properties dialog (see

General Menu

for rasters and

General Menu

for vectors). If your layer already has a CRS defined, it will be displayed as shown in

Vector Layer Properties

Dialog .

Vihje: CRS in the Map Legend

Right-clicking on a layer in the Map Legend (section

Map Legend ) provides two CRS shortcuts. Set layer CRS

takes you directly to the Coordinate Reference System Selector dialog (see

figure_projection_2 ). Set project CRS

from Layer redefines the project CRS using the layer’s CRS.

10.3 Define On The Fly (OTF) Reprojection

QGIS supports OTF reprojection for both raster and vector data. However, OTF is not activated by default. To use

OTF projection, you must activate the Enable on the fly CRS transformation checkbox in the CRS tab of the

Project Properties dialog.

There are three ways to do this:

1. Select Project Properties from the Project (Gnome, OSX) or Settings (KDE, Windows) menu.

2. Click on the

CRS status icon in the lower right-hand corner of the status bar.

3. Turn OTF on by default in the CRS tab of the Options dialog by selecting Enable ‘on the fly’ reprojection by default or Automatically enable ‘on the fly’ reprojection if layers have different CRS.

If you have already loaded a layer and you want to enable OTF projection, the best practice is to open the CRS tab of the Project Properties dialog, select a CRS, and activate the Enable ‘on the fly’ CRS transformation checkbox. The

CRS status shown next to the icon.

icon will no longer be greyed out, and all layers will be OTF projected to the CRS

The CRS tab of the Project Properties dialog contains five important components, as shown in

Figure_projection_2

and described below:

1. Enable ‘on the fly’ CRS transformation — This checkbox is used to enable or disable OTF projection.

When off, each layer is drawn using the coordinates as read from the data source, and the components described below are inactive. When on, the coordinates in each layer are projected to the coordinate reference system defined for the map canvas.

2. Filter — If you know the EPSG code, the identifier, or the name for a coordinate reference system, you can use the search feature to find it. Enter the EPSG code, the identifier or the name.

3. Recently used coordinate reference systems — If you have certain CRSs that you frequently use in your everyday GIS work, these will be displayed in this list. Click on one of these items to select the associated

CRS.

4. Coordinate reference systems of the world — This is a list of all CRSs supported by QGIS, including

Geographic, Projected and Custom coordinate reference systems. To define a CRS, select it from the list by expanding the appropriate node and selecting the CRS. The active CRS is preselected.

5. PROJ.4 text — This is the CRS string used by the PROJ.4 projection engine. This text is read-only and provided for informational purposes.

Vihje: Project Properties Dialog

If you open the Project Properties dialog from the Project menu, you must click on the CRS tab to view the CRS settings.

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Kuva 10.2: Project Properties Dialog

Opening the dialog from the

CRS status icon will automatically bring the CRS tab to the front.

10.4 Custom Coordinate Reference System

If QGIS does not provide the coordinate reference system you need, you can define a custom CRS. To define a

CRS, select Custom CRS...

from the Settings menu. Custom CRSs are stored in your QGIS user database. In addition to your custom CRSs, this database also contains your spatial bookmarks and other custom data.

Defining a custom CRS in QGIS requires a good understanding of the PROJ.4 projection library. To begin, refer to

“Cartographic Projection Procedures for the UNIX Environment - A User’s Manual” by Gerald I. Evenden, U.S.

Geological Survey Open-File Report 90-284, 1990 (available at ftp://ftp.remotesensing.org/proj/OF90-284.pdf

).

This manual describes the use of the proj.4 and related command line utilities. The cartographic parameters used with proj.4 are described in the user manual and are the same as those used by QGIS.

The Custom Coordinate Reference System Definition dialog requires only two parameters to define a user CRS:

1. A descriptive name

2. The cartographic parameters in PROJ.4 format

To create a new CRS, click the

Add new CRS button and enter a descriptive name and the CRS parameters.

Note that the Parameters must begin with a +proj= block, to represent the new coordinate reference system.

You can test your CRS parameters to see if they give sane results. To do this, enter known WGS 84 latitude and longitude values in North and East fields, respectively. Click on [Calculate], and compare the results with the known values in your coordinate reference system.

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10.5 Default datum transformations

OTF depends on being able to transform data into a ‘default CRS’, and QGIS uses WGS84. For some CRS there are a number of transforms available. QGIS allows you to define the transformation used otherwise QGIS uses a default transformation.

In the CRS tab under Settings → Options you can:

• set QGIS to ask you when it needs define a transformation using Ask for datum transformation when no default is defined

• edit a list of user defaults for transformations.

.

QGIS asks which transformation to use by opening a dialogue box displaying PROJ.4 text describing the source and destination transforms. Further information may be found by hovering over a transform. User defaults can be saved by selecting Remember selection .

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QGIS Browser

The QGIS Browser is a panel in QGIS that lets you easily navigate in your filesystem and manage geodata. You can have access to common vector files (e.g., ESRI shapefiles or MapInfo files), databases (e.g., PostGIS, Oracle,

SpatiaLite or MS SQL Spatial) and WMS/WFS connections. You can also view your GRASS data (to get the data into QGIS, see

GRASS GIS Integration

).

Kuva 11.1: QGIS browser as a stand alone application

Use the QGIS Browser to preview your data. The drag-and-drop function makes it easy to get your data into the map view and the map legend.

1. Activate the QGIS Browser: Right-click on the toolbar and check Browser or select it from Settings →

Panels .

2. Drag the panel into the legend window and release it.

3. Click on the Browser tab.

4. Browse in your filesystem and choose the shapefile folder from qgis_sample_data directory.

5. Press the Shift key and select the airports.shp and alaska.shp files.

6. Press the left mouse button, then drag and drop the files into the map canvas.

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7. Right-click on a layer and choose Set project CRS from layer. For more information see

Working with

Projections .

8. Click on

Zoom Full to make the layers visible.

There is a second browser available under Settings → Panels. This is handy when you need to move files or layers between locations.

1. Activate a second QGIS Browser: Right-click on the toolbar and check Browser (2) , or select it from

Settings

→ Panels.

2. Drag the panel into the legend window.

3. Navigate to the Browser (2) tab and browse for a shapefile in your file system.

4. Select a file with the left mouse button. Now you can use the current project.

Add Selected Layers icon to add it into the

QGIS automatically looks for the coordinate reference system (CRS) and zooms to the layer extent if you work in a blank QGIS project. If there are already files in your project, the file will just be added, and in the case that it has the same extent and CRS, it will be visualized. If the file has another CRS and layer extent, you must first right-click on the layer and choose Set Project CRS from Layer. Then choose Zoom to Layer Extent.

The

Filter files function works on a directory level. Browse to the folder where you want to filter files and enter a search word or wildcard. The Browser will show only matching filenames – other data won’t be displayed.

It’s also possible to run the QGIS Browser as a stand-alone application.

Start the QGIS browser

• Type in “qbrowser” at a command prompt.

• Start the QGIS Browser using the Start menu or desktop shortcut.

.

• The QGIS Browser is available from your Applications folder.

In

figure_browser_standalone_metadata , you can see the enhanced functionality of the stand-alone QGIS Browser.

The Param tab provides the details of your connection-based datasets, like PostGIS or MSSQL Spatial. The

Metadata tab contains general information about the file (see

Metadata Menu ). With the Preview tab, you can

have a look at your files without importing them into your QGIS project. It’s also possible to preview the attributes of your files in the Attributes tab.

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Työskentely vektoridatalla

.

12.1 Tuetut datan formaatit

QGIS uses the OGR library to read and write vector data formats, including ESRI shapefiles, MapInfo and MicroStation file formats, AutoCAD DXF, PostGIS, SpatiaLite, Oracle Spatial and MSSQL Spatial databases, and many more. GRASS vector and PostgreSQL support is supplied by native QGIS data provider plugins. Vector data can also be loaded in read mode from zip and gzip archives into QGIS. As of the date of this document, 69 vector formats are supported by the OGR library (see OGR-SOFTWARE-SUITE in

Literature and Web References ). The

complete list is available at http://www.gdal.org/ogr/ogr_formats.html

.

Muista: Not all of the listed formats may work in QGIS for various reasons. For example, some require external commercial libraries, or the GDAL/OGR installation of your OS may not have been built to support the format you want to use. Only those formats that have been well tested will appear in the list of file types when loading a vector into QGIS. Other untested formats can be loaded by selecting *.*.

Working with GRASS vector data is described in Section

GRASS GIS Integration .

This section describes how to work with several common formats: ESRI shapefiles, PostGIS layers, SpatiaLite layers, OpenStreetMap vectors, and Comma Separated data (CSV). Many of the features available in QGIS work the same, regardless of the vector data source. This is by design, and it includes the identify, select, labeling and attributes functions.

12.1.1 ESRI shapetiedostot

The standard vector file format used in QGIS is the ESRI shapefile. Support is provided by the OGR Simple

Feature Library ( http://www.gdal.org/ogr/ ).

A shapefile actually consists of several files. The following three are required:

1. .shp file containing the feature geometries

2. .dbf file containing the attributes in dBase format

3. .shx index file

Shapefiles also can include a file with a .prj suffix, which contains the projection information. While it is very useful to have a projection file, it is not mandatory. A shapefile dataset can contain additional files. For further details, see the ESRI technical specification at http://www.esri.com/library/whitepapers/pdfs/shapefile.pdf

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Loading a Shapefile

To load a shapefile, start QGIS and click on the

Add Vector Layer

This will bring up a new window (see

figure_vector_1 ).

toolbar button, or simply press Ctrl+Shift+V.

Kuva 12.1: Add Vector Layer Dialog

From the available options check File . Click on [Browse]. That will bring up a standard open file dialog (see

figure_vector_2 ), which allows you to navigate the file system and load a shapefile or other supported data source.

The selection box Filter allows you to preselect some OGR-supported file formats.

You can also select the encoding for the shapefile if desired.

Kuva 12.2: Open an OGR Supported Vector Layer Dialog

Selecting a shapefile from the list and clicking [Open] loads it into QGIS.

Figure_vector_3

shows QGIS after loading the alaska.shp file.

Vihje: Tason värit

When you add a layer to the map, it is assigned a random color. When adding more than one layer at a time, different colors are assigned to each layer.

Once a shapefile is loaded, you can zoom around it using the map navigation tools. To change the style of a layer, open the Layer Properties dialog by double clicking on the layer name or by right-clicking on the name in the

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Kuva 12.3: QGIS with Shapefile of Alaska loaded legend and choosing Properties from the context menu. See section

Style Menu

for more information on setting symbology of vector layers.

Vihje: Load layer and project from mounted external drives on OS X

On OS X, portable drives that are mounted beside the primary hard drive do not show up as expected under File

→ Open Project. We are working on a more OSX-native open/save dialog to fix this. As a workaround, you can type /Volumes in the File name box and press Enter. Then you can navigate to external drives and network mounts.

Improving Performance for Shapefiles

To improve the performance of drawing a shapefile, you can create a spatial index. A spatial index will improve the speed of both zooming and panning. Spatial indexes used by QGIS have a .qix extension.

Use these steps to create the index:

• Load a shapefile by clicking on the

Add Vector Layer toolbar button or pressing Ctrl+Shift+V.

• Open the Layer Properties dialog by double-clicking on the shapefile name in the legend or by right-clicking and choosing Properties from the context menu.

• In the General tab, click the [Create Spatial Index] button.

Problem loading a shape .prj file

If you load a shapefile with a .prj file and QGIS is not able to read the coordinate reference system from that file, you will need to define the proper projection manually within the General tab of the Layer Properties dialog

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of the layer by clicking the [Specify...] button. This is due to the fact that .prj files often do not provide the complete projection parameters as used in QGIS and listed in the CRS dialog.

For the same reason, if you create a new shapefile with QGIS, two different projection files are created: a .prj

file with limited projection parameters, compatible with ESRI software, and a .qpj file, providing the complete parameters of the used CRS. Whenever QGIS finds a .qpj file, it will be used instead of the .prj.

12.1.2 Loading a MapInfo Layer

To load a MapInfo layer, click on the file type filter Files of type layer you want to load.

Add Vector Layer toolbar button; or type Ctrl+Shift+V, change the

: to ‘Mapinfo File [OGR] (*.mif *.tab *.MIF *.TAB)’ and select the MapInfo

12.1.3 Loading an ArcInfo Binary Coverage

To load an ArcInfo Binary Coverage, click on the

Add Vector Layer toolbar button or press Ctrl+Shift+V to open the Add Vector Layer dialog. Select Directory as Source type. Change the file type filter Files of type to ‘Arc/Info Binary Coverage’. Navigate to the directory that contains the coverage file, and select it.

Similarly, you can load directory-based vector files in the UK National Transfer Format, as well as the raw TIGER

Format of the US Census Bureau.

12.1.4 Delimited Text Files

Tabular data is a very common and widely used format because of its simplicity and readability – data can be viewed and edited even in a plain text editor. A delimited text file is an attribute table with each column separated by a defined character and each row separated by a line break. The first row usually contains the column names. A common type of delimited text file is a CSV (Comma Separated Values), with each column separated by a comma.

Such data files can also contain positional information in two main forms:

• As point coordinates in separate columns

• As well-known text (WKT) representation of geometry

QGIS allows you to load a delimited text file as a layer or ordinal table. But first check that the file meets the following requirements:

1. The file must have a delimited header row of field names. This must be the first line in the text file.

2. The header row must contain field(s) with geometry definition. These field(s) can have any name.

3. The X and Y coordinates (if geometry is defined by coordinates) must be specified as numbers. The coordinate system is not important.

As an example of a valid text file, we import the elevation point data file elevp.csv that comes with the QGIS sample dataset (see section

Sample Data

):

X;Y;ELEV

300120 ; 7689960 ; 13

654360 ; 7562040 ; 52

1640 ; 7512840 ; 3

[ ...

]

Some items to note about the text file:

1. The example text file uses ; (semicolon) as delimiter. Any character can be used to delimit the fields.

2. The first row is the header row. It contains the fields X, Y and ELEV.

3. No quotes (") are used to delimit text fields.

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4. The X coordinates are contained in the X field.

5. The Y coordinates are contained in the Y field.

Loading a delimited text file

Click the toolbar icon

Add Delimited Text Layer in the Manage layers toolbar to open the Create a Layer from a

Delimited Text File dialog, as shown in

figure_delimited_text_1 .

Kuva 12.4: Delimited Text Dialog

First, select the file to import (e.g., qgis_sample_data/csv/elevp.csv) by clicking on the [Browse] button. Once the file is selected, QGIS attempts to parse the file with the most recently used delimiter. To enable

QGIS to properly parse the file, it is important to select the correct delimiter. You can specify a delimiter by activating Custom delimiters , or by activating Regular expression delimiter and entering text into the

Expression field. For example, to change the delimiter to tab, use \t (this is a regular expression for the tab character).

Once the file is parsed, set Geometry definition to Point coordinates and choose the X and Y fields from the dropdown lists. If the coordinates are defined as degrees/minutes/seconds, activate the

DMS coordinates checkbox.

Finally, enter a layer name (e.g., elevp), as shown in

figure_delimited_text_1 . To add the layer to the map, click

[OK]. The delimited text file now behaves as any other map layer in QGIS.

There is also a helper option that allows you to trim leading and trailing spaces from fields —

Also, it is possible to

Trim fields

.

Discard empty fields . If necessary, you can force a comma to be the decimal separator by activating Decimal separator is comma .

If spatial information is represented by WKT, activate the Well Known Text option and select the field with the

WKT definition for point, line or polygon objects. If the file contains non-spatial data, activate

(attribute only table) and it will be loaded as an ordinal table.

No geometry

Additionaly, you can enable:

Use spatial index to improve the performance of displaying and spatially selecting features.

Use subset index .

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• Watch file to watch for changes to the file by other applications while QGIS is running.

12.1.5 OpenStreetMap data

In recent years, the OpenStreetMap project has gained popularity because in many countries no free geodata such as digital road maps are available. The objective of the OSM project is to create a free editable map of the world from GPS data, aerial photography or local knowledge. To support this objective, QGIS provides suppport for

OSM data.

Loading OpenStreetMap Vectors

QGIS integrates OpenStreetMap import as a core functionality.

• To connect to the OSM server and download data, open the menu Vector → Openstreetmap → Load data.

You can skip this step if you already obtained an .osm XML file using JOSM, Overpass API or any other source.

• The menu Vector → Openstreetmap → Import topology from an XML file will convert your .osm file into a SpatiaLite database and create a corresponding database connection.

• The menu Vector → Openstreetmap → Export topology to SpatiaLite then allows you to open the database connection, select the type of data you want (points, lines, or polygons) and choose tags to import. This creates a SpatiaLite geometry layer that you can add to your project by clicking on the

Add SpatiaLite Layer toolbar button or by selecting the

SpatiaLite Layers

).

Add SpatiaLite Layer...

option from the Layer menu (see section

12.1.6 PostGIS Layers

PostGIS layers are stored in a PostgreSQL database. The advantages of PostGIS are the spatial indexing, filtering and query capabilities it provides. Using PostGIS, vector functions such as select and identify work more accurately than they do with OGR layers in QGIS.

Creating a stored Connection

The first time you use a PostGIS data source, you must create a connection to the PostgreSQL database that contains the data. Begin by clicking on the

Add PostGIS Layer toolbar button, selecting the Add PostGIS

Layer...

option from the Layer menu, or typing Ctrl+Shift+D. You can also open the Add Vector Layer dialog and select

Database

. The Add PostGIS Table(s) dialog will be displayed. To access the connection manager, click on the [New] button to display the Create a New PostGIS Connection dialog. The parameters required for a connection are:

• Name: A name for this connection. It can be the same as Database.

• Service: Service parameter to be used alternatively to hostname/port (and potentially database). This can be defined in pg_service.conf.

• Host: Name of the database host. This must be a resolvable host name such as would be used to open a telnet connection or ping the host. If the database is on the same computer as QGIS, simply enter ‘localhost’ here.

• Port: Port number the PostgreSQL database server listens on. The default port is 5432.

• Database: Name of the database.

• SSL mode: How the SSL connection will be negotiated with the server. Note that massive speedups in

PostGIS layer rendering can be achieved by disabling SSL in the connection editor. The following options are available:

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– Disable: Only try an unencrypted SSL connection.

– Allow: Try a non-SSL connection. If that fails, try an SSL connection.

– Prefer (the default): Try an SSL connection. If that fails, try a non-SSL connection.

– Require: Only try an SSL connection.

• Username: User name used to log in to the database.

• Password: Password used with Username to connect to the database.

Optionally, you can activate the following checkboxes:

Save Username

Save Password

Only look in the geometry_columns table

Don’t resolve type of unrestricted columns (GEOMETRY)

Only look in the ‘public’ schema

• Also list tables with no geometry

• Use estimated table metadata

Once all parameters and options are set, you can test the connection by clicking on the [Test Connect] button.

Loading a PostGIS Layer

Once you have one or more connections defined, you can load layers from the PostgreSQL database. Of course, this requires having data in PostgreSQL. See section

Importing Data into PostgreSQL

for a discussion on importing data into the database.

To load a layer from PostGIS, perform the following steps:

• If the Add PostGIS layers dialog is not already open, selecting the

Layer menu or typing Ctrl+Shift+D opens the dialog.

• Choose the connection from the drop-down list and click [Connect].

Add PostGIS Layer...

option from the

• Select or unselect Also list tables with no geometry .

• Optionally, use some Search Options to define which features to load from the layer, or use the [Build query] button to start the Query builder dialog.

• Find the layer(s) you wish to add in the list of available layers.

• Select it by clicking on it. You can select multiple layers by holding down the Shift key while clicking.

See section

Query Builder

for information on using the PostgreSQL Query Builder to further define the layer.

• Click on the [Add] button to add the layer to the map.

Vihje: PostGIS Layers

Normally, a PostGIS layer is defined by an entry in the geometry_columns table. From version 0.9.0 on, QGIS can load layers that do not have an entry in the geometry_columns table. This includes both tables and views.

Defining a spatial view provides a powerful means to visualize your data. Refer to your PostgreSQL manual for information on creating views.

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Some details about PostgreSQL layers

This section contains some details on how QGIS accesses PostgreSQL layers. Most of the time, QGIS should simply provide you with a list of database tables that can be loaded, and it will load them on request. However, if you have trouble loading a PostgreSQL table into QGIS, the information below may help you understand any

QGIS messages and give you direction on changing the PostgreSQL table or view definition to allow QGIS to load it.

QGIS requires that PostgreSQL layers contain a column that can be used as a unique key for the layer. For tables, this usually means that the table needs a primary key, or a column with a unique constraint on it. In QGIS, this column needs to be of type int4 (an integer of size 4 bytes). Alternatively, the ctid column can be used as primary key. If a table lacks these items, the oid column will be used instead. Performance will be improved if the column is indexed (note that primary keys are automatically indexed in PostgreSQL).

If the PostgreSQL layer is a view, the same requirement exists, but views do not have primary keys or columns with unique constraints on them. You have to define a primary key field (has to be integer) in the QGIS dialog before you can load the view. If a suitable column does not exist in the view, QGIS will not load the layer. If this occurs, the solution is to alter the view so that it does include a suitable column (a type of integer and either a primary key or with a unique constraint, preferably indexed).

QGIS offers a checkbox Select at id that is activated by default. This option gets the ids without the attributes which is faster in most cases. It can make sense to disable this option when you use expensive views.

12.1.7 Importing Data into PostgreSQL

Data can be imported into PostgreSQL/PostGIS using several tools, including the SPIT plugin and the command line tools shp2pgsql and ogr2ogr.

DB Manager

QGIS comes with a core plugin named

DB Manager

. It can be used to load shapefiles and other data formats, and it includes support for schemas. See section

DB Manager Plugin

for more information.

shp2pgsql

PostGIS includes an utility called shp2pgsql that can be used to import shapefiles into a PostGIS-enabled database.

For example, to import a shapefile named lakes.shp into a PostgreSQL database named gis_data, use the following command: shp2pgsql -s 2964 lakes.shp lakes_new | psql gis_data

This creates a new layer named lakes_new in the gis_data database. The new layer will have a spatial reference identifier (SRID) of 2964. See section

Working with Projections

for more information on spatial reference systems and projections.

Vihje: Exporting datasets from PostGIS

Like the import tool shp2pgsql, there is also a tool to export PostGIS datasets as shapefiles: pgsql2shp. This is shipped within your PostGIS distribution.

ogr2ogr

Besides shp2pgsql and DB Manager, there is another tool for feeding geodata in PostGIS: ogr2ogr. This is part of your GDAL installation.

To import a shapefile into PostGIS, do the following:

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ogr2ogr -f "PostgreSQL" PG:"dbname=postgis host=myhost.de user=postgres password=topsecret" alaska.shp

This will import the shapefile alaska.shp into the PostGIS database postgis using the user postgres with the password topsecret on host server myhost.de.

Note that OGR must be built with PostgreSQL to support PostGIS. You can verify this by typing (in ) ogrinfo --formats | grep -i post

If you prefer to use PostgreSQL’s COPY command instead of the default INSERT INTO method, you can export the following environment variable (at least available on and ): export PG_USE_COPY=YES ogr2ogr does not create spatial indexes like shp2pgsl does. You need to create them manually, using the normal SQL command CREATE INDEX afterwards as an extra step (as described in the next section

Improving

Performance ).

Improving Performance

Retrieving features from a PostgreSQL database can be time-consuming, especially over a network. You can improve the drawing performance of PostgreSQL layers by ensuring that a PostGIS spatial index exists on each layer in the database. PostGIS supports creation of a GiST (Generalized Search Tree) index to speed up spatial searches of the data (GiST index information is taken from the PostGIS documentation available at http://postgis.refractions.net

).

The syntax for creating a GiST index is:

CREATE INDEX [indexname] ON [tablename]

USING GIST ( [geometryfield] GIST_GEOMETRY_OPS );

Note that for large tables, creating the index can take a long time. Once the index is created, you should perform a

VACUUM ANALYZE . See the PostGIS documentation (POSTGIS-PROJECT

Literature and Web References ) for

more information.

The following is an example of creating a GiST index: [email protected]:~/current$ psql gis_data

Welcome to psql 8.3.0, the PostgreSQL interactive terminal.

Type: \copyright for distribution terms

\h for help with SQL commands

\? for help with psql commands

\g or terminate with semicolon to execute query

\q to quit gis_data=# CREATE INDEX sidx_alaska_lakes ON alaska_lakes gis_data-# USING GIST (the_geom GIST_GEOMETRY_OPS);

CREATE INDEX gis_data=# VACUUM ANALYZE alaska_lakes;

VACUUM gis_data=# \q [email protected]:~/current$

12.1.8 Vector layers crossing 180° longitude

Many GIS packages don’t wrap vector maps with a geographic reference system (lat/lon) crossing the 180 degrees longitude line ( http://postgis.refractions.net/documentation/manual-2.0/ST_Shift_Longitude.html

). As result, if we open such a map in QGIS, we will see two far, distinct locations, that should appear near each other. In

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Figure_vector_4 , the tiny point on the far left of the map canvas (Chatham Islands) should be within the grid, to

the right of the New Zealand main islands.

Kuva 12.5: Map in lat/lon crossing the 180° longitude line

A work-around is to transform the longitude values using PostGIS and the ST_Shift_Longitude function. This function reads every point/vertex in every component of every feature in a geometry, and if the longitude coordinate is < 0°, it adds 360° to it. The result is a 0° - 360° version of the data to be plotted in a 180°-centric map.

Kuva 12.6: Crossing 180° longitude applying the ST_Shift_Longitude function

Usage

• Import data into PostGIS ( Importing Data into PostgreSQL ) using, for example, the DB Manager plugin.

• Use the PostGIS command line interface to issue the following command (in this example, “TABLE” is the actual name of your PostGIS table): gis_data=# update TABLE set the_geom=ST_Shift_Longitude(the_geom);

• If everything went well, you should receive a confirmation about the number of features that were updated.

Then you’ll be able to load the map and see the difference ( Figure_vector_5 ).

12.1.9 SpatiaLite Layers

The first time you load data from a SpatiaLite database, begin by clicking on the

Add SpatiaLite Layer toolbar button, or by selecting the Add SpatiaLite Layer...

option from the Layer menu, or by typing Ctrl+Shift+L.

This will bring up a window that will allow you either to connect to a SpatiaLite database already known to QGIS, which you can choose from the drop-down menu, or to define a new connection to a new database. To define a new connection, click on [New] and use the file browser to point to your SpatiaLite database, which is a file with a .sqlite extension.

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If you want to save a vector layer to SpatiaLite format, you can do this by right clicking the layer in the legend.

Then, click on Save as.., define the name of the output file, and select ‘SpatiaLite’ as format and the CRS. Also, you can select ‘SQLite’ as format and then add SPATIALITE=YES in the OGR data source creation option field.

This tells OGR to create a SpatiaLite database. See also http://www.gdal.org/ogr/drv_sqlite.html

.

QGIS also supports editable views in SpatiaLite.

Creating a new SpatiaLite layer

If you want to create a new SpatiaLite layer, please refer to section

Creating a new SpatiaLite layer .

Vihje: SpatiaLite data management Plugins

For SpatiaLite data management, you can also use several Python plugins: QSpatiaLite, SpatiaLite Manager or

DB Manager (core plugin, recommended). If necessary, they can be downloaded and installed with the Plugin

Installer.

12.1.10 MSSQL Spatial Layers

QGIS also provides native MS SQL 2008 support. The first time you load MSSQL Spatial data, begin by clicking on the

Add MSSQL Spatial Layer toolbar button or by selecting the from the Layer menu, or by typing Ctrl+Shift+M.

Add MSSQL Spatial Layer...

option

12.1.11 Oracle Spatial Layers

The spatial features in Oracle Spatial aid users in managing geographic and location data in a native type within an Oracle database. QGIS now has support for such layers.

Creating a stored Connection

The first time you use an Oracle Spatial data source, you must create a connection to the database that contains the data. Begin by clicking on the

Add Orcale Spatial Layer toolbar button, selecting the Add Orcale

Spatial Layer...

option from the Layer menu, or typing Ctrl+Shift+O. To access the connection manager, click on the [New] button to display the Create a New Oracle Spatial Connection dialog. The parameters required for a connection are:

• Name: A name for this connection. It can be the same as Database

• Database: SID or SERVICE_NAME of the Oracle instance.

• Host: Name of the database host. This must be a resolvable host name such as would be used to open a telnet connection or ping the host. If the database is on the same computer as QGIS, simply enter ‘localhost’ here.

• Port: Port number the PostgreSQL database server listens on. The default port is 1521.

• Username: Username used to login to the database.

• Password: Password used with Username to connect to the database.

Optionally, you can activate following checkboxes:

Save Username

Save Password

Indicates whether to save the database username in the connection configuration.

Indicates whether to save the database password in the connection settings.

• Only look in meta data table Restricts the displayed tables to those that are in the all_sdo_geom_metadata view. This can speed up the initial display of spatial tables.

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• Only look for user’s tables When searching for spatial tables, restrict the search to tables that are owned by the user.

• Also list tables with no geometry Indicates that tables without geometry should also be listed by default.

Use estimated table statistics for the layer metadata

When the layer is set up, various metadata are required for the Oracle table. This includes information such as the table row count, geometry type and spatial extents of the data in the geometry column. If the table contains a large number of rows, determining this metadata can be time-consuming. By activating this option, the following fast table metadata operations are done: Row count is determined from all_tables.num_rows. Table extents are always determined with the SDO_TUNE.EXTENTS_OF function, even if a layer filter is applied. Table geometry is determined from the first 100 non-null geometry rows in the table.

• Only existing geometry types Only list the existing geometry types and don’t offer to add others.

Once all parameters and options are set, you can test the connection by clicking on the [Test Connect] button.

Vihje: QGIS User Settings and Security

Depending on your computing environment, storing passwords in your QGIS settings may be a security risk.

Passwords are saved in clear text in the system configuration and in the project files! Your customized settings for

QGIS are stored based on the operating system:

• The settings are stored in your home directory in ~/.qgis2.

• The settings are stored in the registry.

Loading an Oracle Spatial Layer

.

Once you have one or more connections defined, you can load layers from the Oracle database. Of course, this requires having data in Oracle.

To load a layer from Oracle Spatial, perform the following steps:

Add Oracle Spatial Layer toolbar • If the Add Oracle Spatial layers dialog is not already open, click on the button.

• Choose the connection from the drop-down list and click [Connect].

• Select or unselect Also list tables with no geometry .

• Optionally, use some Search Options to define which features to load from the layer or use the [Build query] button to start the Query builder dialog.

• Find the layer(s) you wish to add in the list of available layers.

• Select it by clicking on it. You can select multiple layers by holding down the Shift key while clicking.

See section

Query Builder

for information on using the Oracle Query Builder to further define the layer.

• Click on the [Add] button to add the layer to the map.

Vihje: Oracle Spatial Layers

Normally, an Oracle Spatial layer is defined by an entry in the USER_SDO_METADATA table.

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12.2 The Symbol Library

12.2.1 Presentation

The Symbol Library is the place where users can create generic symbols to be used in several QGIS projects. It allows users to export and import symbols, groups symbols and add, edit and remove symbols. You can open it with the Settings → Style Library or from the Style tab in the vector layer’s Properties.

Share and import symbols

Users can export and import symbols in two main formats: qml (QGIS format) and SLD (OGC standard). Note that SLD format is not fully supported by QGIS.

share item displays a drop down list to let the user import or export symbols.

Groups and smart groups

Groups are categories of Symbols and smart groups are dynamic groups.

To create a group, right-click on an existing group or on the main Groups directory in the left of the library. You can also select a group and click on the add item button.

To add a symbol into a group, you can either right click on a symbol then choose Apply group and then the group name added before. There is a second way to add several symbols into group: just select a group and click and choose Group Symbols. All symbols display a checkbox that allow you to add the symbol into the selected groups. When finished, you can click on the same button, and choose Finish Grouping.

Create Smart Symbols is similar to creating group, but instead select Smart Groups. The dialog box allow user to choose the expression to select symbols in order to appear in the smart group (contains some tags, member of a group, have a string in its name, etc.)

Add, edit, remove symbol

With the Style manager from the [Symbol] menu you can manage your symbols. You can add item

, edit item

, remove item and share item

. ‘Marker’ symbols, ‘Line’ symbols, ‘Fill’ patterns and ‘colour ramps’ can be used to create the symbols. The symbols are then assigned to ‘All Symbols’, ‘Groups’ or ‘Smart groups’.

For each kind of symbols, you will find always the same dialog structure:

• at the top left side a symbol representation

• under the symbol representation the symbol tree show the symbol layers

• at the right you can setup some parameter (unit,transparency, color, size and rotation)

• under these parameteres you find some symbol from the symbol library

The symbol tree allow adding, removing or protect new simple symbol. You can move up or down the symbol layer.

More detailed settings can be made when clicking on the second level in the Symbol layers dialog. You can define

Symbol layers that are combined afterwards. A symbol can consist of several Symbol layers. Settings will be shown later in this chapter.

Vihje: Note that once you have set the size in the lower levels of the Symbol layers dialog, the size of the whole symbol can be changed with the Size menu in the first level again. The size of the lower levels changes accordingly, while the size ratio is maintained.

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12.2.2 Marker Symbols

Marker symbols have several symbol layer types:

• Ellipse marker

• Font marker

• Simple marker (default)

• SVG marker

• Vector Field marker

The following settings are possible:

• Symbol layer type: You have the option to use Ellipse markers, Font markers, Simple markers, SVG markers and Vector Field markers.

• colors

• Size

• Outline style

• Outline width

• Angle

• Offset X,Y: You can shift the symbol in the x- or y-direction.

• Anchor point

• Data defined properties ...

12.2.3 Line Symbols

Line marker symbols have only two symbol layer types:

• Marker line

• Simple line (default)

The default symbol layer type draws a simple line whereas the other display a marker point regularly on the line.

You can choose different location vertex, interval or central point. Marker line can have offset along the line or offset line. Finally, rotation allows you to change the orientation of the symbol.

The following settings are possible:

• colour

• Pen width

• Offset

• Pen style

• Join style

• Cap style

• Use custom dash pattern

• Dash pattern unit

• Data defined properties ...

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12.2.4 Polygon Symbols

Polygon marker symbols have also several symbol layer types:

• Centroid fill

• Gradient fill

• Line pattern fill

• Point pattern fill

• SVG fill

• Shapeburst fille

• Simple fill (default)

• Outline: Marker line (same as line marker)

• Outline: simple line (same as line marker)

The following settings are possible:

• Colors for the border and the fill.

• Fill style

• Border style

• Border width

• Offset X,Y

• Data defined properties ...

Using the color combo box, you can drag and drop color for one color button to another button, copy-paste color, pick color from somewhere, choose a color from the palette or from recent or standard color. The combo box allow you to fill in the feature with transparency. You can also just clic on the button to open the palettte dialog.

Note that you can import color from some external software like GIMP.

‘Gradient Fill’ Symbol layer type allows you to select between a Two color and Color ramp setting. You can use the

Feature centroid as Referencepoint. All fills ‘Gradient Fill‘ Symbol layer type is also available through the Symbol menu of the Categorized and Graduated Renderer and through the Rule properties menu of the Rule-based renderer. Other possibility is to choose a ‘shapeburst fill’ which is a buffered gradient fill, where a gradient is drawn from the boundary of a polygon towards the polygon’s centre. Configurable parameters include distance from the boundary to shade, use of color ramps or simple two color gradients, optional blurring of the fill and offsets.

It is possible to only draw polygon borders inside the polygon. Using ‘Outline: Simple line’ select only inside polygon .

Draw line

12.2.5 Color ramp

You can create a custom color ramp choosing New color ramp... from the color ramp drop-down menu. A dialog will prompt for the ramp type: Gradient, Random, colorBrewer, or cpt-city. The first three have options for number of steps and/or multiple stops in the color ramp. You can use the Invert option while classifying the data with a color ramp. See

figure_symbology_3

for an example of custom color ramp and

figure_symbology_3a

for the cpt-city dialog.

.

The cpt-city option opens a new dialog with hundreds of themes included ‘out of the box’.

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12.3 The Vector Properties Dialog

The Layer Properties dialog for a vector layer provides information about the layer, symbology settings and labeling options. If your vector layer has been loaded from a PostgreSQL/PostGIS datastore, you can also alter the underlying SQL for the layer by invoking the Query Builder dialog on the General tab. To access the Layer

Properties dialog, double-click on a layer in the legend or right-click on the layer and select Properties from the pop-up menu.

Kuva 12.9: Vector Layer Properties Dialog

12.3.1 Style Menu

The Style menu provides you with a comprehensive tool for rendering and symbolizing your vector data. You can use Layer rendering → tools that are common to all vector data, as well as special symbolizing tools that were designed for the different kinds of vector data.

Renderers

The renderer is responsible for drawing a feature together with the correct symbol. There are four types of renderers: single symbol, categorized, graduated and rule-based. There is no continuous color renderer, because it is in fact only a special case of the graduated renderer. The categorized and graduated renderers can be created by specifying a symbol and a color ramp - they will set the colors for symbols appropriately. For point layers, there is a point displacement renderer available. For each data type (points, lines and polygons), vector symbol layer types are available. Depending on the chosen renderer, the Style menu provides different additional sections. On the bottom right of the symbology dialog, there is a [Symbol] button, which gives access to the Style Manager

(see

Presentation ). The Style Manager allows you to edit and remove existing symbols and add new ones.

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After having made any needed changes, the symbol can be added to the list of current style symbols (using

[Symbol] Save in symbol library ), and then it can easily be used in the future. Furthermore, you can use the [Save Style] button to save the symbol as a QGIS layer style file (.qml) or SLD file (.sld). SLDs can be exported from any type of renderer – single symbol, categorized, graduated or rule-based – but when importing an SLD, either a single symbol or rule-based renderer is created. That means that categorized or graduated styles are converted to rule-based. If you want to preserve those renderers, you have to stick to the QML format. On the other hand, it can be very handy sometimes to have this easy way of converting styles to rule-based.

If you change the renderer type when setting the style of a vector layer the settings you made for the symbol will be maintained. Be aware that this procedure only works for one change. If you repeat changing the renderer type the settings for the symbol will get lost.

If the datasource of the layer is a database (PostGIS or Spatialite for example), you can save your layer style inside a table of the database. Just clic on :guilabel:‘ Save Style‘ comboxbox and choose Save in database item then fill in the dialog to define a style name, add a description, an ui file and if the style is a default style. When loading a layer from the database, if a style already exists for this layer, QGIS will load the layer and its style. You can add several style in the database. Only one will be the default style anyway.

Kuva 12.10: Save Style in database Dialog

Vihje: Select and change multiple symbols

The Symbology allows you to select multiple symbols and right click to change color, transparency, size, or width of selected entries.

Single Symbol Renderer

The Single Symbol Renderer is used to render all features of the layer using a single user-defined symbol. The properties, which can be adjusted in the Style menu, depend partially on the type of layer, but all types share the following dialog structure. In the top-left part of the menu, there is a preview of the current symbol to be rendered.

On the right part of the menu, there is a list of symbols already defined for the current style, prepared to be used by selecting them from the list. The current symbol can be modified using the menu on the right side. If you click on the first level in the Symbol layers dialog on the left side, it’s possible to define basic parameters like Size,

Transparency , color and Rotation. Here, the layers are joined together.

Categorized Renderer

The Categorized Renderer is used to render all features from a layer, using a single user-defined symbol whose color reflects the value of a selected feature’s attribute. The Style menu allows you to select:

• The attribute (using the Column listbox or the

• The symbol (using the Symbol dialog)

Set column expression function, see

Expressions )

• The colors (using the color Ramp listbox)

Then click on Classify button to create classes from the distinct value of the attribute column. Each classes can be disabled unchecking the checkbox at the left of the class name.

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You can change symbol, value and/or label of the clic, just double clicking on the item you want to change.

Right-clic shows a contextual menu to Copy/Paste, Change color, Change transparency, Change output unit,

Change symbol width.

The [Advanced] button in the lower-right corner of the dialog allows you to set the fields containing rotation and size scale information. For convenience, the center of the menu lists the values of all currently selected attributes together, including the symbols that will be rendered.

The example in

figure_symbology_2

shows the category rendering dialog used for the rivers layer of the QGIS sample dataset.

Graduated Renderer

The Graduated Renderer is used to render all the features from a layer, using a single user-defined symbol whose color reflects the assignment of a selected feature’s attribute to a class.

Like the Categorized Renderer, the Graduated Renderer allows you to define rotation and size scale from specified columns.

Also, analogous to the Categorized Renderer, the Style tab allows you to select:

• The attribute (using the Column listbox or the

• The symbol (using the Symbol Properties button)

Set column expression function, see

Expressions

chapter)

• The colors (using the color Ramp list)

Additionally, you can specify the number of classes and also the mode for classifying features within the classes

(using the Mode list). The available modes are:

• Equal Interval: each class has the same size (e.g. values from 0 to 16 and 4 classes, each class has a size of

4);

• Quantile: each class will have the same number of element inside (the idea of a boxplot);

• Natural Breaks (Jenks): the variance within each class is minimal while the variance between classes is maximal;

• Standard Deviation: classes are built depending on the standard deviation of the values;

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• Pretty Breaks: the same of natural breaks but the extremes number of each class are integers.

The listbox in the center part of the Style menu lists the classes together with their ranges, labels and symbols that will be rendered.

Click on Classify button to create classes using the choosen mode. Each classes can be disabled unchecking the checkbox at the left of the class name.

You can change symbol, value and/or label of the clic, just double clicking on the item you want to change.

Right-clic shows a contextual menu to Copy/Paste, Change color, Change transparency, Change output unit,

Change symbol width.

The example in

figure_symbology_4

shows the graduated rendering dialog for the rivers layer of the QGIS sample dataset.

Vihje: Thematic maps using an expression

Categorized and graduated thematic maps can now be created using the result of an expression. In the properties dialog for vector layers, the attribute chooser has been augmented with a Set column expression function. So now you no longer need to write the classification attribute to a new column in your attribute table if you want the classification attribute to be a composite of multiple fields, or a formula of some sort.

Rule-based rendering

The Rule-based Renderer is used to render all the features from a layer, using rule based symbols whose color reflects the assignment of a selected feature’s attribute to a class. The rules are based on SQL statements. The dialog allows rule grouping by filter or scale, and you can decide if you want to enable symbol levels or use only the first-matched rule.

The example in

figure_symbology_5

shows the rule-based rendering dialog for the rivers layer of the QGIS sample dataset.

To create a rule, activate an existing row by double-clicking on it, or click on ‘+’ and click on the new rule. In the Rule properties dialog, you can define a label for the rule. Press the button to open the expression string builder. In the Function List, click on Fields and Values to view all attributes of the attribute table to be searched.

To add an attribute to the field calculator Expression field, double click its name in the Fields and Values list.

Generally, you can use the various fields, values and functions to construct the calculation expression, or you can just type it into the box (see

Expressions

). You can create a new rule by copying and pasting an existing rule with

the right mouse button. You can also use the ‘ELSE’ rule that will be run if none of the other rules on that level match. Since QGIS 2.6 the label for the rules appears in a pseudotree in the map legend. Just double-klick the rules in the map legend and the Style menu of the layer properties appears showing the rule that is the background for the symbol in the pseudotree.

Point displacement

The Point Displacement Renderer works to visualize all features of a point layer, even if they have the same location. To do this, the symbols of the points are placed on a displacement circle around a center symbol.

Vihje: Export vector symbology

You have the option to export vector symbology from QGIS into Google *.kml, *.dxf and MapInfo *.tab files. Just open the right mouse menu of the layer and click on Save selection as → to specify the name of the output file and its format. In the dialog, use the Symbology export menu to save the symbology either as Feature symbology → or as Symbol layer symbology →. If you have used symbol layers, it is recommended to use the second setting.

Inverted Polygon

Inverted polygon renderer allows user to define a symbol to fill in outside of the layer’s polygons. As before you can select a subrenderers. These subrenderers are the same as for the main renderers.

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Color Picker

Regardless the type of style to be used, the select color dialog will show when you click to choose a color either border or fill color. This dialog has four different tabs which allow you to select colors by color ramp

, color wheel

, color swatches or color picker

.

Whatever method you use, the selected color is always described through color sliders for HSV (Hue, Saturation,

Value) and RGB (Red, Green, Blue) values. There is also an opacity slider to set transparency level. On the lower left part of the dialog you can see a comparison between the current and the new color you are presently selecting and on the lower right part you have the option to add the color you just tweaked into a color slot button.

With color ramp or with color wheel

, you can browse to all possible color combinations. There are other possibilities though. By using color swatches you can choose from a preselected list. This selected list is populated with one of three methods: Recent colors, Standard colors or Project colors

Another option is to use the color picker which allows you to sample a color from under your mouse pointer at any part of QGIS or even from another application by pressing the space bar. Please note that the color picker is

OS dependent and is currently not supported by OSX.

Vihje: quick color picker + copy/paste colors

You can quickly choose from Recent colors, from Standard colors or simply copy or paste a color by clicking the drop-down arrow that follows a current color box.

Layer rendering

• Layer transparency : You can make the underlying layer in the map canvas visible with this tool. Use the slider to adapt the visibility of your vector layer to your needs. You can also make a precise

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definition of the percentage of visibility in the the menu beside the slider.

• Layer blending mode and Feature blending mode: You can achieve special rendering effects with these tools that you may previously only know from graphics programs. The pixels of your overlaying and underlaying layers are mixed through the settings described below.

– Normal: This is the standard blend mode, which uses the alpha channel of the top pixel to blend with the pixel beneath it. The colors aren’t mixed.

– Lighten: This selects the maximum of each component from the foreground and background pixels.

Be aware that the results tend to be jagged and harsh.

– Screen: Light pixels from the source are painted over the destination, while dark pixels are not. This mode is most useful for mixing the texture of one layer with another layer (e.g., you can use a hillshade to texture another layer).

– Dodge: Dodge will brighten and saturate underlying pixels based on the lightness of the top pixel. So, brighter top pixels cause the saturation and brightness of the underlying pixels to increase. This works best if the top pixels aren’t too bright; otherwise the effect is too extreme.

– Addition: This blend mode simply adds pixel values of one layer with the other. In case of values above one (in the case of RGB), white is displayed. This mode is suitable for highlighting features.

– Darken: This creates a resultant pixel that retains the smallest components of the foreground and background pixels. Like lighten, the results tend to be jagged and harsh.

– Multiply: Here, the numbers for each pixel of the top layer are multiplied with the corresponding pixels for the bottom layer. The results are darker pictures.

– Burn: Darker colors in the top layer cause the underlying layers to darken. Burn can be used to tweak and colorise underlying layers.

– Overlay: This mode combines the multiply and screen blending modes. In the resulting picture, light parts become lighter and dark parts become darker.

– Soft light: This is very similar to overlay, but instead of using multiply/screen it uses color burn/dodge.

This is supposed to emulate shining a soft light onto an image.

– Hard light: Hard light is also very similar to the overlay mode. It’s supposed to emulate projecting a very intense light onto an image.

– Difference: Difference subtracts the top pixel from the bottom pixel, or the other way around, to always get a positive value. Blending with black produces no change, as the difference with all colors is zero.

– Subtract: This blend mode simply subtracts pixel values of one layer from the other. In case of negative values, black is displayed.

12.3.2 Labels Menu

The

Labels core application provides smart labeling for vector point, line and polygon layers, and it only requires a few parameters. This new application also supports on-the-fly transformed layers. The core functions of the application have been redesigned. In QGIS, there are a number of other features that improve the labeling.

The following menus have been created for labeling the vector layers:

• Text

• Formatting

• Buffer

• Background

• Shadow

• Placement

• Rendering

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Let us see how the new menus can be used for various vector layers. Labeling point layers

Start QGIS and load a vector point layer. Activate the layer in the legend and click on the icon in the QGIS toolbar menu.

Layer Labeling Options

The first step is to activate the

Label this layer with checkbox and select an attribute column to use for labeling.

Click if you want to define labels based on expressions - See

labeling_with_expressions .

The following steps describe a simple labeling without using the Data defined override functions, which are situated next to the drop-down menus.

You can define the text style in the Text menu (see

Figure_labels_1

). Use the Type case option to influence the text rendering. You have the possibility to render the text ‘All uppercase’, ‘All lowercase’ or ‘Capitalize first letter’.

Use the blend modes to create effects known from graphics programs (see

blend_modes ).

In the Formatting menu, you can define a character for a line break in the labels with the ‘Wrap on character’ function. Use the Formatted numbers option to format the numbers in an attribute table. Here, decimal places may be inserted. If you enable this option, three decimal places are initially set by default.

To create a buffer, just activate the Draw text buffer checkbox in the Buffer menu. The buffer color is variable.

Here, you can also use blend modes (see

blend_modes ).

If the color buffer’s fill checkbox is activated, it will interact with partially transparent text and give mixed color transparency results. Turning off the buffer fill fixes that issue (except where the interior aspect of the buffer’s stroke intersects with the text’s fill) and also allows you to make outlined text.

In the Background menu, you can define with Size X and Size Y the shape of your background. Use Size type to insert an additional ‘Buffer’ into your background. The buffer size is set by default here. The background then consists of the buffer plus the background in Size X and Size Y. You can set a Rotation where you can choose between ‘Sync with label’, ‘Offset of label’ and ‘Fixed’. Using ‘Offset of label’ and ‘Fixed’, you can rotate the background. Define an Offset X,Y with X and Y values, and the background will be shifted. When applying Radius

X,Y , the background gets rounded corners. Again, it is possible to mix the background with the underlying layers in the map canvas using the Blend mode (see

blend_modes ).

Use the Shadow menu for a user-defined Drop shadow. The drawing of the background is very variable. Choose between ‘Lowest label component’, ‘Text’, ‘Buffer’ and ‘Background’. The Offset angle depends on the orientation of the label. If you choose the Use global shadow checkbox, then the zero point of the angle is always oriented to the north and doesn’t depend on the orientation of the label. You can influence the appearance of the shadow with the Blur radius. The higher the number, the softer the shadows. The appearance of the drop shadow can also be altered by choosing a blend mode (see

blend_modes ).

Choose the Placement menu for the label placement and the labeling priority. Using the Offset from point setting, you now have the option to use Quadrants to place your label. Additionally, you can alter the angle of the label placement with the Rotation setting. Thus, a placement in a certain quadrant with a certain rotation is possible.

In the Rendering menu, you can define label and feature options. Under Label options, you find the scale-based visibility setting now. You can prevent QGIS from rendering only selected labels with the Show all labels for this layer (including colliding labels) checkbox. Under Feature options, you can define whether every part of a multipart feature is to be labeled. It’s possible to define whether the number of features to be labeled is limited and to Discourage labels from covering features .

Labeling line layers

The first step is to activate the Label this layer checkbox in the Label settings tab and select an attribute column to use for labeling. Click if you want to define labels based on expressions - See

labeling_with_expressions .

After that, you can define the text style in the Text menu. Here, you can use the same settings as for point layers.

Also, in the Formatting menu, the same settings as for point layers are possible.

The Buffer menu has the same functions as described in section

labeling_point_layers .

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The Background menu has the same entries as described in section

labeling_point_layers .

Also, the Shadow menu has the same entries as described in section

labeling_point_layers .

In the Placement menu, you find special settings for line layers. The label can be placed Parallel , Curved or Horizontal . With the Parallel and Curved option, you can define the position Above line ,

On line and Below line . It’s possible to select several options at once. In that case, QGIS will look for the optimal position of the label. Remember that here you can also use the line orientation for the position of the label.

Additionally, you can define a Maximum angle between curved characters when selecting the Curved option

(see

Figure_labels_2

).

You can set up a minimum distance for repeating labels. Distance can be in mm or in map units.

Some Placement setup will display more options, for example, Curved and Parallel Placements will allow the user to set up the position of the label (above, belw or on the line), distance from the line and for Curved, the user can also setup inside/outside max angle between curved label.

The Rendering menu has nearly the same entries as for point layers. In the Feature options, you can now Suppress labeling of features smaller than .

Labeling polygon layers

The first step is to activate the

Click

Label this layer checkbox and select an attribute column to use for labeling.

if you want to define labels based on expressions - See

labeling_with_expressions .

In the Text menu, define the text style. The entries are the same as for point and line layers.

The Formatting menu allows you to format multiple lines, also similar to the cases of point and line layers.

As with point and line layers, you can create a text buffer in the Buffer menu.

Use the Background menu to create a complex user-defined background for the polygon layer. You can use the menu also as with the point and line layers.

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The entries in the Shadow menu are the same as for point and line layers.

In the Placement menu, you find special settings for polygon layers (see

Figure_labels_3 ).

Offset from centroid ,

Horizontal (slow) , Around centroid , Free and Using perimeter are possible.

In the Offset from centroid settings, you can specify if the centroid is of the visible polygon or whole polygon . That means that either the centroid is used for the polygon you can see on the map or the centroid is determined for the whole polygon, no matter if you can see the whole feature on the map. You can place your label with the quadrants here, and define offset and rotation. The Around centroid setting makes it possible to place the label around the centroid with a certain distance. Again, you can define visible polygon or whole polygon for the centroid. With the Using perimeter settings, you can define a position and a distance for the label. For the position, Above line , On line , Below line and Line orientation dependent position are possible.

Related to the choose of Label Placement, several options will appear. As for Point Placement you can choose the distance for the polygon outline, repeat the label around the polygon perimeter.

The entries in the Rendering menu are the same as for line layers. You can also use Suppress labeling of features smaller than in the Feature options. Define labels based on expressions

QGIS allows to use expressions to label features. Just click the icon in the

Labels menu of the properties dialog. In

figure_labels_4

you see a sample expression to label the alaska regions with name and area size, based on the field ‘NAME_2’, some descriptive text and the function ‘$area()’ in combination with ‘format_number()’ to make it look nicer.

Expression based labeling is easy to work with. All you have to take care of is, that you need to combine all elements (strings, fields and functions) with a string concatenation sign ‘||’ and that fields a written in “double quotes” and strings in ‘single quotes’. Let’s have a look at some examples:

# label based on two fields ’name’ and ’place’ with a comma as separater

"name" || ’, ’ || "place"

-> John Smith, Paris

# label based on two fields ’name’ and ’place’ separated by comma

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’My name is ’ || "name" || ’and I live in ’ || "place"

-> My name is John Smith and I live in Paris

# label based on two fields ’name’ and ’place’ with a descriptive text

# and a line break (\n)

’My name is ’ || "name" || ’\nI live in ’ || "place"

-> My name is John Smith

I live in Paris

# create a multi-line label based on a field and the $area function

# to show the place name and its area size based on unit meter.

’The area of ’ || "place" || ’has a size of ’ || $area || ’m²’

-> The area of Paris has a size of 105000000 m²

# create a CASE ELSE condition. If the population value in field

# population is <= 50000 it is a town, otherwise a city.

’This place is a ’ || CASE WHEN "population <= 50000" THEN ’town’ ELSE ’city’ END

-> This place is a town

As you can see in the expression builder, you have hundreds if functions available to create simple and very complex expressions to label your data in QGIS. See

Expressions

chapter for more information and example on expressions.

Using data-defined override for labeling

With the data-defined override functions, the settings for the labeling are overridden by entries in the attribute table. You can activate and deactivate the function with the right-mouse button. Hover over the symbol and you see the information about the data-defined override, including the current definition field. We now describe an example using the data-defined override function for the

Move label function (see

figure_labels_5

).

1. Import lakes.shp from the QGIS sample dataset.

2. Double-click the layer to open the Layer Properties. Click on Labels and Placement. Select Offset from centroid

.

3. Look for the Data defined entries. Click the icon to define the field type for the Coordinate. Choose

‘xlabel’ for X and ‘ylabel’ for Y. The icons are now highlighted in yellow.

4. Zoom into a lake.

5. Go to the Label toolbar and click the icon. Now you can shift the label manually to another position

(see

figure_labels_6

). The new position of the label is saved in the ‘xlabel’ and ‘ylabel’ columns of the attribute table.

12.3.3 Fields Menu

Within the Fields menu, the field attributes of the selected dataset can be manipulated. The buttons

New Column and

Delete Column can be used when the dataset is in

Editing mode

.

Edit Widget

Within the Fields menu, you also find an edit widget column. This column can be used to define values or a range of values that are allowed to be added to the specific attribute table column. If you click on the [edit widget] button, a dialog opens, where you can define different widgets. These widgets are:

• Checkbox: Displays a checkbox, and you can define what attribute is added to the column when the checkbox is activated or not.

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• Classification: Displays a combo box with the values used for classification, if you have chosen ‘unique value’ as legend type in the Style menu of the properties dialog.

• Color: Displays a color button allowing user to choose a color from the color dialog window.

• Date/Time: Displays a line fields which can opens a calendar widget to enter a date, a time or both. Column type must be text. You can select a custom format, pop-up a calendar, etc.

• Enumeration: Opens a combo box with values that can be used within the columns type. This is currently only supported by the PostgreSQL provider.

• File name: Simplifies the selection by adding a file chooser dialog.

• Hidden: A hidden attribute column is invisible. The user is not able to see its contents.

• Photo: Field contains a filename for a picture. The width and height of the field can be defined.

• Range: Allows you to set numeric values from a specific range. The edit widget can be either a slider or a spin box.

• Relation Reference: This widged lets you embed the feature form of the referenced layer on the feature form of the actual layer. See

Creating one to many relations .

• Text edit (default): This opens a text edit field that allows simple text or multiple lines to be used. If you choose multiple lines you can also choose html content.

• Unique values: You can select one of the values already used in the attribute table. If ‘Editable’ is activated, a line edit is shown with autocompletion support, otherwise a combo box is used.

• UUID Generator: Generates a read-only UUID (Universally Unique Identifiers) field, if empty.

• Value map: A combo box with predefined items. The value is stored in the attribute, the description is shown in the combo box. You can define values manually or load them from a layer or a CSV file.

• Value Relation: Offers values from a related table in a combobox. You can select layer, key column and value column.

• Webview: Field contains a URL. The width and height of the field is variable.

With the Attribute editor layout, you can now define built-in forms for data entry jobs (see

figure_fields_2 ).

Choose ‘Drag and drop designer’ and an attribute column. Use the icon to create a category that will then be shown during the digitizing session (see

figure_fields_3 ). The next step will be to assign the relevant fields to the

category with the icon. You can create more categories and use the same fields again. When creating a new category, QGIS will insert a new tab for the category in the built-in form.

Other options in the dialog are ‘Autogenerate’ and ‘Provide ui-file’. ‘Autogenerate’ just creates editors for all fields and tabulates them. The ‘Provide ui-file’ option allows you to use complex dialogs made with the Qt-

Designer. Using a UI-file allows a great deal of freedom in creating a dialog. For detailed information, see http://nathanw.net/2011/09/05/qgis-tips-custom-feature-forms-with-python-logic/ .

QGIS dialogs can have a Python function that is called when the dialog is opened. Use this function to add extra logic to your dialogs. An example is (in module MyForms.py): def open(dialog,layer,feature): geom = feature.geometry() control = dialog.findChild(QWidged,"My line edit")

Reference in Python Init Function like so: MyForms.open

MyForms.py must live on PYTHONPATH, in .qgis2/python, or inside the project folder.

12.3.4 General Menu

Use this menu to make general settings for the vector layer. There are several options available:

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Layer Info

• Change the display name of the layer in displayed as

• Define the Layer source of the vector layer

• Define the Data source encoding to define provider-specific options and to be able to read the file

Coordinate Reference System

• Specify the coordinate reference system. Here, you can view or change the projection of the specific vector layer.

• Create a Spatial Index (only for OGR-supported formats)

• Update Extents information for a layer

• View or change the projection of the specific vector layer, clicking on Specify ...

Scale dependent visibility

• You can set the Maximum (inclusive) and Minimum (exclusive) scale. The scale can also be set by the

[Current] buttons.

Feature subset

• With the [Query Builder] button, you can create a subset of the features in the layer that will be visualized

(also refer to section

Query Builder ).

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12.3.5 Rendering Menu

QGIS 2.2 introduces support for on-the-fly feature generalisation. This can improve rendering times when drawing many complex features at small scales. This feature can be enabled or disabled in the layer settings using the

Simplify geometry option. There is also a new global setting that enables generalisation by default for newly added layers (see section

Options

). Note: Feature generalisation may introduce artefacts into your rendered output

in some cases. These may include slivers between polygons and inaccurate rendering when using offset-based symbol layers.

12.3.6 Display Menu

This menu is specifically created for Map Tips. It includes a new feature: Map Tip display text in HTML.

While you can still choose a Field to be displayed when hovering over a feature on the map, it is now possible to insert HTML code that creates a complex display when hovering over a feature. To activate Map Tips, select the menu option View → MapTips. Figure Display 1 shows an example of HTML code.

Kuva 12.30: HTML code for map tip

12.3.7 Actions Menu

QGIS provides the ability to perform an action based on the attributes of a feature. This can be used to perform any number of actions, for example, running a program with arguments built from the attributes of a feature or passing parameters to a web reporting tool.

Actions are useful when you frequently want to run an external application or view a web page based on one or more values in your vector layer. They are divided into six types and can be used like this:

• Generic, Mac, Windows and Unix actions start an external process.

• Python actions execute a Python expression.

• Generic and Python actions are visible everywhere.

• Mac, Windows and Unix actions are visible only on the respective platform (i.e., you can define three ‘Edit’ actions to open an editor and the users can only see and execute the one ‘Edit’ action for their platform to run the editor).

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There are several examples included in the dialog. You can load them by clicking on [Add default actions]. One example is performing a search based on an attribute value. This concept is used in the following discussion.

Defining Actions

Attribute actions are defined from the vector Layer Properties dialog. To define an action, open the vector Layer

Properties dialog and click on the Actions menu. Go to the Action properties. Select ‘Generic’ as type and provide a descriptive name for the action. The action itself must contain the name of the application that will be executed when the action is invoked. You can add one or more attribute field values as arguments to the application. When the action is invoked, any set of characters that start with a % followed by the name of a field will be replaced by the value of that field. The special characters %% will be replaced by the value of the field that was selected from the identify results or attribute table (see

using_actions

below). Double quote marks can be used to group text into a single argument to the program, script or command. Double quotes will be ignored if preceded by a backslash.

If you have field names that are substrings of other field names (e.g., col1 and col10), you should indicate that by surrounding the field name (and the % character) with square brackets (e.g., [%col10]). This will prevent the %col10 field name from being mistaken for the %col1 field name with a 0 on the end. The brackets will be removed by QGIS when it substitutes in the value of the field. If you want the substituted field to be surrounded by square brackets, use a second set like this: [[%col10]].

Using the Identify Features tool, you can open the Identify Results dialog. It includes a (Derived) item that contains information relevant to the layer type. The values in this item can be accessed in a similar way to the other fields by preceeding the derived field name with (Derived).. For example, a point layer has an X and Y field, and the values of these fields can be used in the action with %(Derived).X and %(Derived).Y. The derived attributes are only available from the Identify Results dialog box, not the Attribute Table dialog box.

Two example actions are shown below:

• konqueror http://www.google.com/search?q=%nam

• konqueror http://www.google.com/search?q=%%

In the first example, the web browser konqueror is invoked and passed a URL to open. The URL performs a

Google search on the value of the nam field from our vector layer. Note that the application or script called by the action must be in the path, or you must provide the full path. To be certain, we could rewrite the first example as: /opt/kde3/bin/konqueror http://www.google.com/search?q=%nam. This will ensure that the konqueror application will be executed when the action is invoked.

The second example uses the %% notation, which does not rely on a particular field for its value. When the action is invoked, the %% will be replaced by the value of the selected field in the identify results or attribute table.

Using Actions

Actions can be invoked from either the Identify Results dialog, an Attribute Table dialog or from Run Feature Action

(recall that these dialogs can be opened by clicking

Identify Features or

Open Attribute Table or

Run Feature Action

). To invoke an action, right click on the record and choose the action from the pop-up menu. Actions are listed in the popup menu by the name you assigned when defining the action. Click on the action you wish to invoke.

If you are invoking an action that uses the %% notation, right-click on the field value in the Identify Results dialog or the Attribute Table dialog that you wish to pass to the application or script.

Here is another example that pulls data out of a vector layer and inserts it into a file using bash and the echo command (so it will only work on or perhaps ). The layer in question has fields for a species name taxon_name, latitude lat and longitude long. We would like to be able to make a spatial selection of localities and export these field values to a text file for the selected record (shown in yellow in the QGIS map area). Here is the action to achieve this: bash -c "echo \"%taxon_name %lat %long\" >> /tmp/species_localities.txt"

After selecting a few localities and running the action on each one, opening the output file will show something like this:

Acacia mearnsii -34.0800000000 150.0800000000

Acacia mearnsii -34.9000000000 150.1200000000

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Acacia mearnsii -35.2200000000 149.9300000000

Acacia mearnsii -32.2700000000 150.4100000000

As an exercise, we can create an action that does a Google search on the lakes layer. First, we need to determine the URL required to perform a search on a keyword. This is easily done by just going to Google and doing a simple search, then grabbing the URL from the address bar in your browser. From this little effort, we see that the format is http://google.com/search?q=qgis , where QGIS is the search term. Armed with this information, we can proceed:

1. Make sure the lakes layer is loaded.

2. Open the Layer Properties dialog by double-clicking on the layer in the legend, or right-click and choose

Properties from the pop-up menu.

3. Click on the Actions menu.

4. Enter a name for the action, for example Google Search.

5. For the action, we need to provide the name of the external program to run. In this case, we can use Firefox.

If the program is not in your path, you need to provide the full path.

6. Following the name of the external application, add the URL used for doing a Google search, up to but not including the search term: http://google.com/search?q=

7. The text in the Action field should now look like this: firefox http://google.com/search?q=

8. Click on the drop-down box containing the field names for the lakes layer. It’s located just to the left of the [Insert Field] button.

9. From the drop-down box, select ‘NAMES’ and click [Insert Field].

10. Your action text now looks like this: firefox http://google.com/search?q=%NAMES

11. To finalize the action, click the [Add to action list] button.

This completes the action, and it is ready to use. The final text of the action should look like this: firefox http://google.com/search?q=%NAMES

We can now use the action. Close the Layer Properties dialog and zoom in to an area of interest. Make sure the lakes layer is active and identify a lake. In the result box you’ll now see that our action is visible:

Kuva 12.33: Select feature and choose action

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When we click on the action, it brings up Firefox and navigates to the URL http://www.google.com/search?q=Tustumena . It is also possible to add further attribute fields to the action.

Therefore, you can add a + to the end of the action text, select another field and click on [Insert Field]. In this example, there is just no other field available that would make sense to search for.

You can define multiple actions for a layer, and each will show up in the Identify Results dialog.

There are all kinds of uses for actions. For example, if you have a point layer containing locations of images or photos along with a file name, you could create an action to launch a viewer to display the image. You could also use actions to launch web-based reports for an attribute field or combination of fields, specifying them in the same way we did in our Google search example.

We can also make more complex examples, for instance, using Python actions.

Usually, when we create an action to open a file with an external application, we can use absolute paths, or eventually relative paths. In the second case, the path is relative to the location of the external program executable file. But what about if we need to use relative paths, relative to the selected layer (a file-based one, like a shapefile or SpatiaLite)? The following code will do the trick: command = "firefox"; imagerelpath = "images_test/test_image.jpg"; layer = qgis.utils.iface.activeLayer(); import os.path; layerpath = layer.source() if layer.providerType() == ’ogr’ else (qgis.core.QgsDataSourceURI(layer.source()).database() if layer.providerType() == ’spatialite’ else None); path = os.path.dirname(str(layerpath)); image = os.path.join(path,imagerelpath); import subprocess; subprocess.Popen( [command, image ] );

We just have to remember that the action is one of type Python and the command and imagerelpath variables must be changed to fit our needs.

But what about if the relative path needs to be relative to the (saved) project file? The code of the Python action would be: command = "firefox" ; imagerelpath = "images/test_image.jpg" ; projectpath = qgis .

core .

QgsProject .

instance() .

fileName();

import os.path

; path = os .

path .

dirname( str (projectpath))

if

projectpath != ’’

else

None ; image = os .

path .

join(path, imagerelpath);

import subprocess

; subprocess .

Popen( [command, image ] );

Another Python action example is the one that allows us to add new layers to the project. For instance, the following examples will add to the project respectively a vector and a raster. The names of the files to be added to the project and the names to be given to the layers are data driven (filename and layername are column names of the table of attributes of the vector where the action was created): qgis .

utils .

iface .

addVectorLayer( ’/yourpath/[% "filename" %].shp’ , ’[% "layername" %]’ ,

’ogr’ )

To add a raster (a TIF image in this example), it becomes: qgis.utils.iface.addRasterLayer(’/yourpath/[% "filename" %].tif’,’[% "layername" %]

’)

12.3.8 Joins Menu

The Joins menu allows you to join a loaded attribute table to a loaded vector layer. After clicking , the

Add vector join dialog appears. As key columns, you have to define a join layer you want to connect with the

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target vector layer. Then, you have to specify the join field that is common to both the join layer and the target layer. Now you can also specify a subset of fields from the joined layer based on the checkbox Choose which fields are joined . As a result of the join, all information from the join layer and the target layer are displayed in the attribute table of the target layer as joined information. If you specified a subset of fields only these fields are displayed in the attribute table of the target layer.

QGIS currently has support for joining non-spatial table formats supported by OGR (e.g., CSV, DBF and Excel), delimited text and the PostgreSQL provider (see

figure_joins_1 ).

Kuva 12.34: Join an attribute table to an existing vector layer

Additionally, the add vector join dialog allows you to:

• Cache join layer in virtual memory

• Create attribute index on the join field

12.3.9 Diagrams Menu

The Diagrams menu allows you to add a graphic overlay to a vector layer (see

figure_diagrams_1 ).

The current core implementation of diagrams provides support for pie charts, text diagrams and histograms.

The menu is divided into four tabs: Appearance, Size, Postion and Options.

In the cases of the text diagram and pie chart, text values of different data columns are displayed one below the other with a circle or a box and dividers. In the Size tab, diagram size is based on a fixed size or on linear scaling according to a classification attribute. The placement of the diagrams, which is done in the Position tab, interacts with the new labeling, so position conflicts between diagrams and labels are detected and solved. In addition, chart positions can be fixed manually.

We will demonstrate an example and overlay on the Alaska boundary layer a text diagram showing temperature data from a climate vector layer. Both vector layers are part of the QGIS sample dataset (see section

Sample Data ).

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1. First, click on the

Load Vector icon, browse to the QGIS sample dataset folder, and load the two vector shape layers alaska.shp and climate.shp.

2. Double click the climate layer in the map legend to open the Layer Properties dialog.

3. Click on the Diagrams menu, activate Display diagrams , and from the Diagram type select ‘Text diagram’.

combo box,

4. In the Appearance tab, we choose a light blue as background color, and in the Size tab, we set a fixed size to 18 mm.

5. In the Position tab, placement could be set to ‘Around Point’.

6. In the diagram, we want to display the values of the three columns T_F_JAN, T_F_JUL and T_F_MEAN.

First select T_F_JAN as Attributes and click the button, then T_F_JUL, and finally T_F_MEAN.

7. Now click [Apply] to display the diagram in the QGIS main window.

8. You can adapt the chart size in the Size tab. Deactivate the Fixed size and set the size of the diagrams on the basis of an attribute with the [Find maximum value] button and the Size menu. If the diagrams appear too small on the screen, you can activate the minimum size of the diagrams.

Increase size of small diagrams checkbox and define the

9. Change the attribute colors by double clicking on the color values in the Assigned attributes field.

Figure_diagrams_2

gives an idea of the result.

10. Finally, click [Ok].

Remember that in the Position tab, a Data defined position of the diagrams is possible. Here, you can use attributes to define the position of the diagram. You can also set a scale-dependent visibility in the Appearance tab.

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Kuva 12.36: Diagram from temperature data overlayed on a map

The size and the attributes can also be an expression. Use the chapter for more information and example.

button to add an expression. See

Expressions

12.3.10 Metadata Menu

The Metadata menu consists of Description, Attribution, MetadataURL and Properties sections.

In the Properties section, you get general information about the layer, including specifics about the type and location, number of features, feature type, and editing capabilities. The Extents table provides you with layer extent information and the Layer Spatial Reference System, which is information about the CRS of the layer. This is a quick way to get information about the layer.

.

Additionally, you can add or edit a title and abstract for the layer in the Description section. It’s also possible to define a Keyword list here. These keyword lists can be used in a metadata catalogue. If you want to use a title from an XML metadata file, you have to fill in a link in the DataUrl field. Use Attribution to get attribute data from an

XML metadata catalogue. In MetadataUrl, you can define the general path to the XML metadata catalogue. This information will be saved in the QGIS project file for subsequent sessions and will be used for QGIS server.

12.4 Expressions

The Expressions feature are available through the field calculator or the add a new column button in the attribut table or the Field tab in the Layer properties ; through the graduaded, categorized and rule-based rendering in the

Style tab of the Layer properties ; through the expression-based labeling in the

; through the feature selection and through the diagram tab of the Layer properties.

Labeling core application

There are powerful way to manipulate attribute value in order to dynamicly change the final value in order to change the geometry style, the content of the label, the value for diagram, select some feature or create virtual column.

12.4.1 Functions List

The Function List contains functions as well as fields and values. View the help function in the Selected Function Help. In Expression you see the calculation expressions you create with the Function List. For the most

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In the Function List, click on Fields and Values to view all attributes of the attribute table to be searched. To add an attribute to the Field calculator Expression field, double click its name in the Fields and Values list. Generally, you can use the various fields, values and functions to construct the calculation expression, or you can just type it into the box. To display the values of a field, you just right click on the appropriate field. You can choose between

Load top 10 unique values and Load all unique values. On the right side, the Field Values list opens with the unique values. To add a value to the Field calculator Expression box, double click its name in the Field Values list.

The Operators, Math, Conversions, String, Geometry and Record groups provide several functions. In Operators , you find mathematical operators. Look in Math for mathematical functions. The Conversions group contains functions that convert one data type to another. The String group provides functions for data strings. In the Geometry group, you find functions for geometry objects. With Record group functions, you can add a numeration to your data set. To add a function to the Field calculator Expression box, click on the > and then double click the function.

Operators

This group contains operators (e.g., +, -, *).

a + b a - b a * b a / b a % b a ^ b a = b a > b a < b a <> b a != b a plus b a minus b a multiplied by b a divided by b a modulo b (for example, 7 % 2 = 1, or 2 fits into 7 three times with remainder 1) a power b (for example, 2^2=4 or 2^3=8) a and b are equal a is larger than b a is smaller than b a and b are not equal a and b are not equal

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a <= b a >= b a ~ b

+ a

- a

||

LIKE

ILIKE a is less than or equal to b a is larger than or equal to b a matches the regular expression b positive sign negative value of a joins two values together into a string ’Hello’ || ’ world’

’string’ returns 1 if the string matches the supplied pattern returns 1 if the string matches case-insensitive the supplied pattern (ILIKE can be used instead of LIKE to make the match case-insensitive)

IS

OR returns 1 if a is the same as b returns 1 when condition a or b is true

AND

NOT returns 1 when condition a and b are true returns 1 if a is not the same as b column name "column name" value of the field column name, take care to not be confused with simple quote, see below a string value, take care to not be confused with double quote, see above

NULL a IS NULL a IS NOT NULL a IN (value[,value]) a NOT IN (value[,value]) null value a has no value a has a value a is below the values listed a is not below the values listed

Some example:

• Joins a string and a value from a column name:

’My feature’s id is: ’ || "gid"

• Test if the “description” attribute field starts with the ‘Hello’ string in the value (note the position of the % caracter):

"description" LIKE ’Hello%’

Conditionals

This group contains functions to handle conditional checks in expressions.

CASE

CASE ELSE coalesce regexp_match evaluates multiple expressions and returns a result evaluates multiple expressions and returns a result returns the first non-NULL value from the expression list returns true if any part of a string matches the supplied regular expression

Some example:

• Send back a value if the first condition is true, else another value:

CASE WHEN "software" LIKE ’%QGIS%’ THEN ’QGIS’ ELSE ’Other’

Mathematical Functions

This group contains math functions (e.g., square root, sin and cos).

sqrt(a) abs sin(a) square root of a returns the absolute value of a number sine of a

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cos(a) tan(a) asin(a) acos(a) atan(a) atan2(y,x) exp ln log10 log round rand randf max min clamp scale_linear scale_exp floor ceil

$pi cosine of a tangent of a arcsin of a arccos of a arctan of a arctan of y/x using the signs of the two arguments to determine the quadrant of the result exponential of a value value of the natural logarithm of the passed expression value of the base 10 logarithm of the passed expression value of the logarithm of the passed value and base round to number of decimal places random integer within the range specified by the minimum and maximum argument (inclusive) random float within the range specified by the minimum and maximum argument (inclusive) largest value in a set of values smallest value in a set of values restricts an input value to a specified range transforms a given value from an input domain to an output range using linear interpolation transforms a given value from an input domain to an output range using an exponential curve rounds a number downwards rounds a number upwards pi as value for calculations

Conversions

This group contains functions to convert one data type to another (e.g., string to integer, integer to string).

toint toreal tostring todatetime todate totime tointerval converts a string to integer number converts a string to real number converts number to string converts a string into Qt data time type converts a string into Qt data type converts a string into Qt time type converts a string to an interval type (can be used to take days, hours, months, etc. off a date)

Date and Time Functions

This group contains functions for handling date and time data.

$now age year month current date and time difference between two dates extract the year part from a date, or the number of years from an interval extract the month part from a date, or the number of months from an interval

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week day hour minute second extract the week number from a date, or the number of weeks from an interval extract the day from a date, or the number of days from an interval extract the hour from a datetime or time, or the number of hours from an interval extract the minute from a datetime or time, or the number of minutes from an interval extract the second from a datetime or time, or the number of minutes from an interval

Some example:

• Get the month and the year of today in the format “10/2014” month($now) || ’/’ || year($now)

String Functions

This group contains functions that operate on strings (e.g., that replace, convert to upper case).

lower upper title trim wordwrap length replace convert string a to lower case convert string a to upper case converts all words of a string to title case (all words lower case with leading capital letter) removes all leading and trailing white space (spaces, tabs, etc.) from a string returns a string wrapped to a maximum/ minimum number of characters length of string a returns a string with the supplied string replaced regexp_replace(a,this,that) returns a string with the supplied regular expression replaced regexp_substr returns the portion of a string which matches a supplied regular expression substr(*a*,from,len) concat strpos returns a part of a string concatenates several strings to one returns the index of a regular expression left right rpad lpad format format_number format_date in a string returns a substring that contains the n leftmost characters of the string returns a substring that contains the n rightmost characters of the string returns a string with supplied width padded using the fill character returns a string with supplied width padded using the fill character formats a string using supplied arguments returns a number formatted with the locale separator for thousands (also truncates the number to the number of supplied places) formats a date type or string into a custom string format

Color Functions

This group contains functions for manipulating colors.

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color_rgb color_rgba ramp_color color_hsl color_hsla color_hsv color_hsva color_cmyk color_cmyka returns a string representation of a color based on its red, green, and blue components returns a string representation of a color based on its red, green, blue, and alpha (transparency) components returns a string representing a color from a color ramp returns a string representation of a color based on its hue, saturation, and lightness attributes returns a string representation of a color based on its hue, saturation, lightness and alpha (transparency) attributes returns a string representation of a color based on its hue, saturation, and value attributes returns a string representation of a color based on its hue, saturation, value and alpha (transparency) attributes returns a string representation of a color based on its cyan, magenta, yellow and black components returns a string representation of a color based on its cyan, magenta, yellow, black and alpha (transparency) components

Geometry Functions

This group contains functions that operate on geometry objects (e.g., length, area).

$geometry

$area

$length

$perimeter

$x

$y xat yat xmin xmax ymin ymax geomFromWKT geomFromGML bbox disjoint returns the geometry of the current feature (can be used for processing with other functions) returns the area size of the current feature returns the length size of the current feature returns the perimeter length of the current feature returns the x coordinate of the current feature returns the y coordinate of the current feature retrieves the nth x coordinate of the current feature.

n given as a parameter of the function retrieves the nth y coordinate of the current feature.

n given as a parameter of the function returns the minimum x coordinate of a geometry.

Calculations are in the Spatial Reference System of this

Geometry returns the maximum x coordinate of a geometry.

Calculations are in the Spatial Reference System of this

Geometry returns the minimum y coordinate of a geometry.

Calculations are in the Spatial Reference System of this

Geometry returns the maximum y coordinate of a geometry.

Calculations are in the Spatial Reference System of this

Geometry returns a geometry created from a well-known text (WKT) representation returns a geometry from a GML representation of geometry intersects touches crosses contains returns 1 if the geometries do not share any space together returns 1 if the geometries spatially intersect

(share any portion of space) and 0 if they don’t returns 1 if the geometries have at least one point in common, but their interiors do not intersect returns 1 if the supplied geometries have some, but not all, interior points in common returns true if and only if no points of b lie in the exterior of a, and at least one point of the interior of b lies in the interior of a

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overlaps within buffer centroid bounds bounds_width bounds_height convexHull difference distance intersection symDifference combine union geomToWKT returns 1 if the geometries share space, are of the same dimension, but are not completely contained by each other returns 1 if geometry a is completely inside geometry b returns a geometry that represents all points whose distance from this geometry is less than or equal to distance returns the geometric center of a geometry returns a geometry which represents the bounding box of an input geometry. Calculations are in the Spatial

Reference System of this Geometry.

returns the width of the bounding box of a geometry.

Calculations are in the Spatial Reference System of this Geometry.

returns the height of the bounding box of a geometry.

Calculations are in the Spatial Reference System of this Geometry.

returns the convex hull of a geometry (this represents the minimum convex geometry that encloses all geometries within the set) returns a geometry that represents that part of geometry a that does not intersect with geometry b returns the minimum distance (based on spatial ref) between two geometries in projected units returns a geometry that represents the shared portion of geometry a and geometry b returns a geometry that represents the portions of a and b that do not intersect returns the combination of geometry a and geometry b returns a geometry that represents the point set union of the geometries returns the well-known text (WKT) representation of the geometry without SRID metadata

Record Functions

This group contains functions that operate on record identifiers.

$rownum

$id

$currentfeature

$scale

$uuid getFeature attribute

$map returns the number of the current row returns the feature id of the current row returns the current feature being evaluated.

This can be used with the ’attribute’ function to evaluate attribute values from the current feature.

returns the current scale of the map canvas generates a Universally Unique Identifier (UUID) for each row. Each UUID is 38 characters long.

returns the first feature of a layer matching a given attribute value.

returns the value of a specified attribute from a feature.

returns the id of the current map item if the map is being drawn in a composition, or "canvas" if the map is being drawn within the main QGIS window.

Fields and Values

Contains a list of fields from the layer. Sample values can also be accessed via right-click.

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Select the field name from the list, then right-click to access a context menu with options to load sample values from the selected field.

.

Fields name should be double-quoted. Values or string should be simple-quoted.

12.5 Editing

QGIS supports various capabilities for editing OGR, SpatiaLite, PostGIS, MSSQL Spatial and Oracle Spatial vector layers and tables.

Muista: The procedure for editing GRASS layers is different - see section

Digitizing and editing a GRASS vector layer

for details.

Vihje: Concurrent Edits

This version of QGIS does not track if somebody else is editing a feature at the same time as you are. The last person to save their edits wins.

12.5.1 Setting the Snapping Tolerance and Search Radius

Before we can edit vertices, we must set the snapping tolerance and search radius to a value that allows us an optimal editing of the vector layer geometries.

Snapping tolerance

Snapping tolerance is the distance QGIS uses to search for the closest vertex and/or segment you are trying to connect to when you set a new vertex or move an existing vertex. If you aren’t within the snapping tolerance,

QGIS will leave the vertex where you release the mouse button, instead of snapping it to an existing vertex and/or segment. The snapping tolerance setting affects all tools that work with tolerance.

1. A general, project-wide snapping tolerance can be defined by choosing Settings → Options . On Mac, go to QGIS → Preferences...

. On Linux: Edit → Options . In the Digitizing tab, you can select between

‘to vertex’, ‘to segment’ or ‘to vertex and segment’ as default snap mode. You can also define a default snapping tolerance and a search radius for vertex edits. The tolerance can be set either in map units or in pixels. The advantage of choosing pixels is that the snapping tolerance doesn’t have to be changed after zoom operations. In our small digitizing project (working with the Alaska dataset), we define the snapping units in feet. Your results may vary, but something on the order of 300 ft at a scale of 1:10000 should be a reasonable setting.

2. A layer-based snapping tolerance can be defined by choosing Settings → (or File →) Snapping options... to enable and adjust snapping mode and tolerance on a layer basis (see

figure_edit_1

).

Note that this layer-based snapping overrides the global snapping option set in the Digitizing tab. So, if you need to edit one layer and snap its vertices to another layer, then enable snapping only on the snap to layer, then decrease the global snapping tolerance to a smaller value. Furthermore, snapping will never occur to a layer that is not checked in the snapping options dialog, regardless of the global snapping tolerance. So be sure to mark the checkbox for those layers that you need to snap to.

Search radius

Search radius is the distance QGIS uses to search for the closest vertex you are trying to move when you click on the map. If you aren’t within the search radius, QGIS won’t find and select any vertex for editing, and it will pop up an annoying warning to that effect. Snap tolerance and search radius are set in map units or pixels, so you may find you need to experiment to get them set right. If you specify too big of a tolerance, QGIS may snap to the

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Kuva 12.38: Edit snapping options on a layer basis wrong vertex, especially if you are dealing with a large number of vertices in close proximity. Set search radius too small, and it won’t find anything to move.

The search radius for vertex edits in layer units can be defined in the Digitizing tab under Settings → Options .

This is the same place where you define the general, project- wide snapping tolerance.

12.5.2 Zooming and Panning

Before editing a layer, you should zoom in to your area of interest. This avoids waiting while all the vertex markers are rendered across the entire layer.

Apart from using the pan and zoom-in

/ zoom-out icons on the toolbar with the mouse, navigating can also be done with the mouse wheel, spacebar and the arrow keys.

Zooming and panning with the mouse wheel

While digitizing, you can press the mouse wheel to pan inside of the main window, and you can roll the mouse wheel to zoom in and out on the map. For zooming, place the mouse cursor inside the map area and roll it forward

(away from you) to zoom in and backwards (towards you) to zoom out. The mouse cursor position will be the center of the zoomed area of interest. You can customize the behavior of the mouse wheel zoom using the Map tools tab under the Settings → Options menu.

Panning with the arrow keys

Panning the map during digitizing is possible with the arrow keys. Place the mouse cursor inside the map area, and click on the right arrow key to pan east, left arrow key to pan west, up arrow key to pan north, and down arrow key to pan south.

You can also use the space bar to temporarily cause mouse movements to pan the map. The PgUp and PgDown keys on your keyboard will cause the map display to zoom in or out without interrupting your digitizing session.

12.5.3 Topological editing

Besides layer-based snapping options, you can also define topological functionalities in the Snapping options...

dialog in the Settings (or File) menu. Here, you can define Enable topological editing , and/or for polygon layers, you can activate the column

Avoid Int.

, which avoids intersection of new polygons.

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Enable topological editing

The option Enable topological editing is for editing and maintaining common boundaries in polygon mosaics.

QGIS ‘detects’ a shared boundary in a polygon mosaic, so you only have to move the vertex once, and QGIS will take care of updating the other boundary.

Avoid intersections of new polygons

The second topological option in the Avoid Int.

column, called Avoid intersections of new polygons, avoids overlaps in polygon mosaics. It is for quicker digitizing of adjacent polygons. If you already have one polygon, it is possible with this option to digitize the second one such that both intersect, and QGIS then cuts the second polygon to the common boundary. The advantage is that you don’t have to digitize all vertices of the common boundary.

Enable snapping on intersections

Another option is to use Enable snapping on intersection . It allows you to snap on an intersection of background layers, even if there’s no vertex on the intersection.

12.5.4 Digitizing an existing layer

By default, QGIS loads layers read-only. This is a safeguard to avoid accidentally editing a layer if there is a slip of the mouse. However, you can choose to edit any layer as long as the data provider supports it, and the underlying data source is writable (i.e., its files are not read-only).

In general, tools for editing vector layers are divided into a digitizing and an advanced digitizing toolbar, described in section

Advanced digitizing . You can select and unselect both under

View

→ Toolbars →. Using the basic digitizing tools, you can perform the following functions:

Icon Purpose Icon Purpose

Current edits

Adding Features: Capture Point

Toggle editing

Adding Features: Capture Line

Adding Features: Capture Polygon

Node Tool

Cut Features

Paste Features

Table Editing: Vector layer basic editing toolbar

Move Feature

Delete Selected

Copy Features

Save layer edits

All editing sessions start by choosing the clicking on the legend entry for a given layer.

Toggle editing option. This can be found in the context menu after right

Alternatively, you can use the Toggle Editing

Toggle editing button from the digitizing toolbar to start or stop the editing mode. Once the layer is in edit mode, markers will appear at the vertices, and additional tool buttons on the editing toolbar will become available.

Vihje: Save Regularly

Remember to

Save Layer Edits regularly. This will also check that your data source can accept all the changes.

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Adding Features

You can use the digitizing mode.

Add Feature

,

Add Feature or

Add Feature icons on the toolbar to put the QGIS cursor into

For each feature, you first digitize the geometry, then enter its attributes. To digitize the geometry, left-click on the map area to create the first point of your new feature.

For lines and polygons, keep on left-clicking for each additional point you wish to capture. When you have finished adding points, right-click anywhere on the map area to confirm you have finished entering the geometry of that feature.

The attribute window will appear, allowing you to enter the information for the new feature.

Figure_edit_2

shows setting attributes for a fictitious new river in Alaska. In the Digitizing menu under the Settings → Options menu, you can also activate Suppress attributes pop-up windows after each created feature and Reuse last entered attribute values .

Kuva 12.39: Enter Attribute Values Dialog after digitizing a new vector feature

With the

Move Feature(s) icon on the toolbar, you can move existing features.

Vihje: Attribute Value Types

For editing, the attribute types are validated during entry. Because of this, it is not possible to enter a number into a text column in the dialog Enter Attribute Values or vice versa. If you need to do so, you should edit the attributes in a second step within the Attribute table dialog.

Current Edits

This feature allows the digitization of multiple layers. Choose made in multiple layers. You also have the opportunity to

Save for Selected Layers to save all changes you

Rollback for Selected Layers , so that the digitization

Cancel for Selected may be withdrawn for all selected layers. If you want to stop editing the selected layers,

Layer(s) is an easy way.

The same functions are available for editing all layers of the project.

Node Tool

For shapefile-based layers as well as SpatialLite, PostgreSQL/PostGIS, MSSQL Spatial, and Oracle Spatial tables, the

Node Tool provides manipulation capabilities of feature vertices similar to CAD programs. It is possible to simply select multiple vertices at once and to move, add or delete them altogether. The node tool also works with

‘on the fly’ projection turned on, and it supports the topological editing feature. This tool is, unlike other tools in

QGIS, persistent, so when some operation is done, selection stays active for this feature and tool. If the node tool is unable to find any features, a warning will be displayed.

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It is important to set the property Settings → Options

→ Digitizing → Search Radius: greater than zero (i.e., 10). Otherwise, QGIS will not be able to tell which vertex is being edited.

to a number

Vihje: Vertex Markers

The current version of QGIS supports three kinds of vertex markers: ‘Semi-transparent circle’, ‘Cross’ and ‘None’.

To change the marker style, choose Options from the Settings menu, click on the Digitizing tab and select the appropriate entry.

Basic operations

Start by activating the of this feature.

Node Tool and selecting a feature by clicking on it. Red boxes will appear at each vertex

• Selecting vertices: You can select vertices by clicking on them one at a time, by clicking on an edge to select the vertices at both ends, or by clicking and dragging a rectangle around some vertices. When a vertex is selected, its color changes to blue. To add more vertices to the current selection, hold down the Ctrl key while clicking. Hold down Ctrl or Shift when clicking to toggle the selection state of vertices (vertices that are currently unselected will be selected as usual, but also vertices that are already selected will become unselected).

• Adding vertices: To add a vertex, simply double click near an edge and a new vertex will appear on the edge near to the cursor. Note that the vertex will appear on the edge, not at the cursor position; therefore, it should be moved if necessary.

• Deleting vertices: After selecting vertices for deletion, click the Delete key. Note that you cannot use the

Node Tool to delete a complete feature; QGIS will ensure it retains the minimum number of vertices for the feature type you are working on. To delete a complete feature use the

Delete Selected tool.

• Moving vertices: Select all the vertices you want to move. Click on a selected vertex or edge and drag in the direction you wish to move. All the selected vertices will move together. If snapping is enabled, the whole selection can jump to the nearest vertex or line.

Each change made with the node tool is stored as a separate entry in the Undo dialog. Remember that all operations support topological editing when this is turned on. On-the-fly projection is also supported, and the node tool provides tooltips to identify a vertex by hovering the pointer over it.

Cutting, Copying and Pasting Features

Selected features can be cut, copied and pasted between layers in the same QGIS project, as long as destination layers are set to

Toggle editing beforehand.

Features can also be pasted to external applications as text. That is, the features are represented in CSV format, with the geometry data appearing in the OGC Well-Known Text (WKT) format.

However, in this version of QGIS, text features from outside QGIS cannot be pasted to a layer within QGIS. When would the copy and paste function come in handy? Well, it turns out that you can edit more than one layer at a time and copy/paste features between layers. Why would we want to do this? Say we need to do some work on a new layer but only need one or two lakes, not the 5,000 on our big_lakes layer. We can create a new layer and use copy/paste to plop the needed lakes into it.

As an example, we will copy some lakes to a new layer:

1. Load the layer you want to copy from (source layer)

2. Load or create the layer you want to copy to (target layer)

3. Start editing for target layer

4. Make the source layer active by clicking on it in the legend

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5. Use the

Select Single Feature tool to select the feature(s) on the source layer

6. Click on the

Copy Features tool

7. Make the destination layer active by clicking on it in the legend

8. Click on the

Paste Features tool

9. Stop editing and save the changes

What happens if the source and target layers have different schemas (field names and types are not the same)?

QGIS populates what matches and ignores the rest. If you don’t care about the attributes being copied to the target layer, it doesn’t matter how you design the fields and data types. If you want to make sure everything - the feature and its attributes - gets copied, make sure the schemas match.

Vihje: Congruency of Pasted Features

If your source and destination layers use the same projection, then the pasted features will have geometry identical to the source layer. However, if the destination layer is a different projection, then QGIS cannot guarantee the geometry is identical. This is simply because there are small rounding-off errors involved when converting between projections.

Deleting Selected Features

If we want to delete an entire polygon, we can do that by first selecting the polygon using the regular

Select Single Feature tool. You can select multiple features for deletion. Once you have the selection set, use the

Delete Selected tool to delete the features.

The

Cut Features tool on the digitizing toolbar can also be used to delete features. This effectively deletes the feature but also places it on a “spatial clipboard”. So, we cut the feature to delete. We could then use the

Paste Features tool to put it back, giving us a one-level undo capability. Cut, copy, and paste work on the currently selected features, meaning we can operate on more than one at a time.

Saving Edited Layers

When a layer is in editing mode, any changes remain in the memory of QGIS. Therefore, they are not committed/saved immediately to the data source or disk. If you want to save edits to the current layer but want to continue editing without leaving the editing mode, you can click the

Save Layer Edits button. When you turn editing mode off with discard them.

Toggle editing

(or quit QGIS for that matter), you are also asked if you want to save your changes or

If the changes cannot be saved (e.g., disk full, or the attributes have values that are out of range), the QGIS inmemory state is preserved. This allows you to adjust your edits and try again.

Vihje: Data Integrity

It is always a good idea to back up your data source before you start editing. While the authors of QGIS have made every effort to preserve the integrity of your data, we offer no warranty in this regard.

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12.5.5 Advanced digitizing

Icon Purpose

Undo

Rotate Feature(s)

Add Ring

Icon Purpose

Redo

Simplify Feature

Add Part

Fill Ring Delete Ring

Delete Part

Offset Curve

Split Parts

Reshape Features

Split Features

Merge Selected Features

Merge Attributes of Selected Features Rotate Point Symbols

Table Advanced Editing: Vector layer advanced editing toolbar

Undo and Redo

The

Undo and

Redo tools allows you to undo or redo vector editing operations. There is also a dockable widget, which shows all operations in the undo/redo history (see

Figure_edit_3 ). This widget is not displayed by

default; it can be displayed by right clicking on the toolbar and activating the Undo/Redo checkbox. Undo/Redo is however active, even if the widget is not displayed.

Kuva 12.40: Redo and Undo digitizing steps

When Undo is hit, the state of all features and attributes are reverted to the state before the reverted operation happened. Changes other than normal vector editing operations (for example, changes done by a plugin), may or may not be reverted, depending on how the changes were performed.

To use the undo/redo history widget, simply click to select an operation in the history list. All features will be reverted to the state they were in after the selected operation.

Rotate Feature(s)

Use

Rotate Feature(s) to rotate one or multiple selected features in the map canvas. You first need to select the features and then press the

Rotate Feature(s) icon. The centroid of the feature(s) appears and will be the rotation anchor point. If you selected multiple features, the rotation anchor point will be the common center of the features.

Press and drag the left mouse button in the desired direction to rotate the selected features.

It’s also possible to create a user-defined rotation anchor point around which the selected feature will rotate. Select the features to rotate and activate the

Rotate Feature(s) tool. Press and hold the Ctrl button and move the mouse

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pointer (without pressing the mouse button) to the place where you want the rotation anchor to be moved. Release the Ctrl button when the desired rotation anchor point is reached. Now, press and drag the left mouse button in the desired direction to rotate the selected feature(s).

Simplify Feature

The

Simplify Feature tool allows you to reduce the number of vertices of a feature, as long as the geometry doesn’t change and geometry type is not a multi geometry. First, select a feature. It will be highlighted by a red rubber band and a slider will appear. Moving the slider, the red rubber band will change its shape to show how the feature is being simplified. Click [OK] to store the new, simplified geometry. If a feature cannot be simplified

(e.g. multi-polygons), a message will appear.

Add Ring

You can create ring polygons using the

Add Ring icon in the toolbar. This means that inside an existing area, it is possible to digitize further polygons that will occur as a ‘hole’, so only the area between the boundaries of the outer and inner polygons remains as a ring polygon.

Add Part

You can add part polygons to a selected multipolygon. The new part polygon must be digitized outside the selected multi-polygon.

Fill Ring

You can use the

Fill Ring function to add a ring to a polygon and add a new feature to the layer at the same time.

Thus you need not first use the

Add Ring icon and then the

Add feature function anymore.

Delete Ring

The

Delete Ring tool allows you to delete ring polygons inside an existing area. This tool only works with polygon layers. It doesn’t change anything when it is used on the outer ring of the polygon. This tool can be used on polygon and multi-polygon features. Before you select the vertices of a ring, adjust the vertex edit tolerance.

Delete Part

The

Delete Part tool allows you to delete parts from multifeatures (e.g., to delete polygons from a multi-polygon feature). It won’t delete the last part of the feature; this last part will stay untouched. This tool works with all multipart geometries: point, line and polygon. Before you select the vertices of a part, adjust the vertex edit tolerance.

Reshape Features

You can reshape line and polygon features using the

Reshape Features icon on the toolbar. It replaces the line or polygon part from the first to the last intersection with the original line. With polygons, this can sometimes lead to unintended results. It is mainly useful to replace smaller parts of a polygon, not for major overhauls, and the reshape line is not allowed to cross several polygon rings, as this would generate an invalid polygon.

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For example, you can edit the boundary of a polygon with this tool. First, click in the inner area of the polygon next to the point where you want to add a new vertex. Then, cross the boundary and add the vertices outside the polygon. To finish, right-click in the inner area of the polygon. The tool will automatically add a node where the new line crosses the border. It is also possible to remove part of the area from the polygon, starting the new line outside the polygon, adding vertices inside, and ending the line outside the polygon with a right click.

Muista: The reshape tool may alter the starting position of a polygon ring or a closed line. So, the point that is represented ‘twice’ will not be the same any more. This may not be a problem for most applications, but it is something to consider.

Offset Curves

The

Offset Curve tool creates parallel shifts of line layers. The tool can be applied to the edited layer (the geometries are modified) or also to background layers (in which case it creates copies of the lines / rings and adds them to the the edited layer). It is thus ideally suited for the creation of distance line layers. The displacement is shown at the bottom left of the taskbar.

To create a shift of a line layer, you must first go into editing mode and then select the feature. You can make the

Offset Curve tool active and drag the cross to the desired distance. Your changes may then be saved with the

Save Layer Edits tool.

QGIS options dialog (Digitizing tab then Curve offset tools section) allows you to configure some parameters like Join style, Quadrant segments, Miter limit.

Split Features

You can split features using the split.

Split Features icon on the toolbar. Just draw a line across the feature you want to

Split parts

In QGIS 2.0 it is now possible to split the parts of a multi part feature so that the number of parts is increased. Just draw a line across the part you want to split using the

Split Parts icon.

Merge selected features

The

Merge Selected Features tool allows you to merge features that have common boundaries. A new dialog will allow you to choose which value to choose between each selected features or select a fonction (Minimum, Maximum, Median, Sum, Skip Attribute) to use for each column.

Merge attributes of selected features

The

Merge Attributes of Selected Features tool allows you to merge attributes of features with common boundaries and attributes without merging their boundaries. First, select several features at once. Then press the

Merge Attributes of Selected Features button. Now QGIS asks you which attributes are to be applied to all selected objects.

As a result, all selected objects have the same attribute entries.

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Rotate Point Symbols

Rotate Point Symbols allows you to change the rotation of point symbols in the map canvas. You must first define a rotation column from the attribute table of the point layer in the Advanced menu of the Style menu of the Layer

Properties . Also, you will need to go into the ‘SVG marker’ and choose Data defined properties .... Activate

Angle and choose ‘rotation’ as field. Without these settings, the tool is inactive.

Kuva 12.41: Rotate Point Symbols

To change the rotation, select a point feature in the map canvas and rotate it, holding the left mouse button pressed.

A red arrow with the rotation value will be visualized (see

Figure_edit_4 ). When you release the left mouse button

again, the value will be updated in the attribute table.

Muista: If you hold the Ctrl key pressed, the rotation will be done in 15 degree steps.

12.5.6 Creating new Vector layers

QGIS allows you to create new shapefile layers, new SpatiaLite layers, and new GPX layers. Creation of a new

GRASS layer is supported within the GRASS plugin. Please refer to section

Creating a new GRASS vector layer

for more information on creating GRASS vector layers.

Creating a new Shapefile layer

To create a new shape layer for editing, choose New → New Shapefile Layer...

from the Layer menu. The New

Vector Layer dialog will be displayed as shown in

Figure_edit_5 . Choose the type of layer (point, line or polygon)

and the CRS (coordinate reference system).

Note that QGIS does not yet support creation of 2.5D features (i.e., features with X,Y,Z coordinates).

To complete the creation of the new shapefile layer, add the desired attributes by clicking on the [Add to attributes list] button and specifying a name and type for the attribute. A first ‘id’ column is added as default but can be removed, if not wanted. Only Type: real , Type: integer , Type: string and Type:date attributes are supported. Additionally and according to the attribute type, you can also define the width and precision of the new attribute column. Once you are happy with the attributes, click [OK] and provide a name for the shapefile. QGIS will automatically add a .shp extension to the name you specify. Once the layer has been created, it will be added to the map, and you can edit it in the same way as described in section

Digitizing an existing layer

above.

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Kuva 12.42: Creating a new Shapefile layer Dialog

Creating a new SpatiaLite layer

To create a new SpatiaLite layer for editing, choose New → New SpatiaLite Layer...

from the Layer menu.

The New SpatiaLite Layer dialog will be displayed as shown in

Figure_edit_6 .

The first step is to select an existing SpatiaLite database or to create a new SpatiaLite database. This can be done with the browse button to the right of the database field. Then, add a name for the new layer, define the layer type, and specify the coordinate reference system with [Specify CRS]. If desired, you can select autoincrementing primary key .

Create an

To define an attribute table for the new SpatiaLite layer, add the names of the attribute columns you want to create with the corresponding column type, and click on the [Add to attribute list] button. Once you are happy with the attributes, click [OK]. QGIS will automatically add the new layer to the legend, and you can edit it in the same way as described in section

Digitizing an existing layer

above.

Further management of SpatiaLite layers can be done with the DB Manager. See

DB Manager Plugin

.

Creating a new GPX layer

To create a new GPX file, you need to load the GPS plugin first. Plugins →

Plugin Manager Dialog. Activate the GPS Tools checkbox.

Plugin Manager...

opens the

When this plugin is loaded, choose New →

Create new GPX Layer...

from the Layer menu. In the Save new

GPX file as dialog, you can choose where to save the new GPX layer.

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Kuva 12.43: Creating a New SpatiaLite layer Dialog

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12.5.7 Working with the Attribute Table

The attribute table displays features of a selected layer. Each row in the table represents one map feature, and each column contains a particular piece of information about the feature. Features in the table can be searched, selected, moved or even edited.

To open the attribute table for a vector layer, make the layer active by clicking on it in the map legend area. Then, from the main Layer menu, choose Open Attribute Table . It is also possible to right click on the layer and choose

Open Attribute Table from the drop-down menu, and to click on the in the Attributes toolbar.

Open Attribute Table button

This will open a new window that displays the feature attributes for the layer ( figure_attributes_1 ). The number of

features and the number of selected features are shown in the attribute table title.

Kuva 12.44: Attribute Table for regions layer

Selecting features in an attribute table

Each selected row in the attribute table displays the attributes of a selected feature in the layer. If the set of features selected in the main window is changed, the selection is also updated in the attribute table. Likewise, if the set of rows selected in the attribute table is changed, the set of features selected in the main window will be updated.

Rows can be selected by clicking on the row number on the left side of the row. Multiple rows can be marked by holding the Ctrl key. A continuous selection can be made by holding the Shift key and clicking on several row headers on the left side of the rows. All rows between the current cursor position and the clicked row are selected. Moving the cursor position in the attribute table, by clicking a cell in the table, does not change the row selection. Changing the selection in the main canvas does not move the cursor position in the attribute table.

The table can be sorted by any column, by clicking on the column header. A small arrow indicates the sort order

(downward pointing means descending values from the top row down, upward pointing means ascending values from the top row down).

For a simple search by attributes on only one column, choose the Column filter → from the menu in the bottom left corner. Select the field (column) on which the search should be performed from the drop-down menu, and hit the [Apply] button. Then, only the matching features are shown in the attribute table.

To make a selection, you have to use the

Select features using an Expression icon on top of the attribute table.

Select features using an Expression allows you to define a subset of a table using a Function List like in the

Field Calculator

(see

Field Calculator ). The query result can then be saved as a new vector layer. For example, if you want to find

regions that are boroughs from regions.shp of the QGIS sample data, you have to open the Fields and Values menu and choose the field that you want to query. Double-click the field ‘TYPE_2’ and also [Load all unique values] . From the list, choose and double-click ‘Borough’. In the Expression field, the following query appears:

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"TYPE_2" = ’Borough’

Here you can also use the Function list → Recent (Selection) to make a selection that you used before. The expression builder remembers the last 20 used expressions.

The matching rows will be selected, and the total number of matching rows will appear in the title bar of the attribute table, as well as in the status bar of the main window. For searches that display only selected features on the map, use the Query Builder described in section

Query Builder .

To show selected records only, use Show Selected Features from the menu at the bottom left.

The other buttons at the top of the attribute table window provide the following functionality:

Toggle editing mode to edit single values and to enable functionalities described below (also with Ctrl+E)

Save Edits

(also with Ctrl+S)

Unselect all

(also with Ctrl+U)

Move selected to top

(also with Ctrl+T)

Invert selection

(also with Ctrl+R)

Copy selected rows to clipboard

(also with Ctrl+C)

Zoom map to the selected rows

(also with Ctrl+J)

Pan map to the selected rows

(also with Ctrl+P)

Delete selected features

(also with Ctrl+D)

New Column for PostGIS layers and for OGR layers with GDAL version >= 1.6 (also with Ctrl+W)

Delete Column for PostGIS layers and for OGR layers with GDAL version >= 1.9 (also with Ctrl+L) •

Open field calculator

(also with Ctrl+I)

Below these buttons is the Field Calculator bar, which allows calculations to be quickly applied attributes visible in the table. This bar uses the same expressions as the

Field Calculator

(see

Field Calculator ).

Vihje: Skip WKT geometry

If you want to use attribute data in external programs (such as Excel), use the

Copy selected rows to clipboard button.

You can copy the information without vector geometries if you deactivate Settings → Options → Data sources menu

Copy geometry in WKT representation from attribute table

.

Save selected features as new layer

The selected features can be saved as any OGR-supported vector format and also transformed into another coordinate reference system (CRS). Just open the right mouse menu of the layer and click on Save as to define the name of the output file, its format and CRS (see section

Map Legend ). To save the selection ensure that the

only selected features is selected. It is also possible to specify OGR creation options within the dialog.

Save

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Paste into new layer

Features that are on the clipboard may be pasted into a new layer. To do this, first make a layer editable. Select some features, copy them to the clipboard, and then paste them into a new layer using Edit → Paste Features as and choosing New vector layer or New memory layer.

This applies to features selected and copied within QGIS and also to features from another source defined using well-known text (WKT).

Working with non spatial attribute tables

QGIS allows you also to load non-spatial tables. This currently includes tables supported by OGR and delimited text, as well as the PostgreSQL, MSSQL and Oracle provider. The tables can be used for field lookups or just generally browsed and edited using the table view. When you load the table, you will see it in the legend field. It can be opened with the

Open Attribute Table tool and is then editable like any other layer attribute table.

As an example, you can use columns of the non-spatial table to define attribute values, or a range of values that are allowed, to be added to a specific vector layer during digitizing. Have a closer look at the edit widget in section

Fields Menu

to find out more.

12.5.8 Creating one to many relations

Relations are a technique often used in databases. The concept is, that features (rows) of different layers (tables) can belong to each other.

As an example you have a layer with all regions of alaska (polygon) which provides some attributes about its name and region type and a unique id (which acts as primary key).

Foreign keys

Then you get another point layer or table with information about airports that are located in the regions and you also want to keep track of these. If you want to add them to the region layer, you need to create a one to many relation using foreign keys, because there are several airports in most regions.

Kuva 12.45: Alaska region with airports

In addition to the already existing attributes in the airports attribute table another field fk_region which acts as a foreign key (if you have a database, you will probably want to define a constraint on it).

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This field fk_region will always contain an id of a region. It can be seen like a pointer to the region it belongs to. And you can design a custom edit form for the editing and QGIS takes care about the setup. It works with different providers (so you can also use it with shape and csv files) and all you have to do is to tell QGIS the relations between your tables.

Layers

QGIS makes no difference between a table and a vector layer. Basically, a vector layer is a table with a geometry.

So can add your table as a vector layer. To demostrate you can load the ‘region’ shapefile (with geometries) and the ‘airport’ csv table (without geometries) and a foreign key (fk_region) to the layer region. This means, that each airport belongs to exactly one region while each region can have any number of airports (a typical one to many relation).

Definition (Relation Manager)

The first thing we are going to do is to let QGIS know about the relations between the layer. This is done in Settings

→ Project Properties. Open the Relations menu and click on Add.

• name is going to be used as a title. It should be a human readable string, describing, what the relation is used for. We will just call say “Airports” in this case.

• referencing layer is the one with the foreign key field on it. In our case this is the airports layer

• referencing field will say, which field points to the other layer so this is fk_region in this case

• referenced layer is the one with the primary key, pointed to, so here it is the regions layer

• referenced field is the primary key of the referenced layer so it is ID

• id will be used for internal purposes and has to be unique. You may need it to build custom forms once this is supported. If you leave it empty, one will be generated for you but you can assign one yourself to get one that is easier to handle.

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Forms

Now that QGIS knows about the relation, it will be used to improve the forms it generates. As we did not change the default form method (autogenerated) it will just add a new widget in our form. So let’s select the layer region in the legend and use the identify tool. Depending on your settings, the form might open directly or you will have to choose to open it in the identification dialog under actions.

Kuva 12.47: Identification dialog regions with relation to airports

As you can see, the airports assigned to this particular region are all shown in a table. And there are also some buttons available. Let’s review them shortly

• The button is for toggling the edit mode. Be aware that it toggles the edit mode of the airport layer, although we are in the feature form of a feature from the region layer. But the table is representing features of the airport layer.

• The button will add a new feature to the airport layer. And it will assign the new airport to the current region by default.

• The button will delete the selected airport permanently.

• The symbol will open a new dialog where you can select any existing airport which will then be assigned to the current region. This may be handy if you created the airport on the wrong region by accident.

• The symbol will unlink the selected airport from the current region, leaving them unassigned (the foreign key is set to NULL) effectively.

• The two buttons to the right switch between table view and form view where the later let’s you view all the airports in their respective form.

.

If you work on the airport table, a new widget type is available which lets you embed the feature form of the referenced region on the feature form of the airports. It can be used when you open the layer properties of the airports table, switch to the Fields menu and change the widget type of the foreign key field ‘fk_region’ to Relation

Reference.

If you look at the feature dialog now, you will see, that the form of the region is embedded inside the airports form and will even have a combobox, which allows you to assign the current airport to another region.

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Kuva 12.48: Identification dialog airport with relation to regions

12.6 Query Builder

The Query Builder allows you to define a subset of a table using a SQL-like WHERE clause and to display the result in the main window. The query result can then be saved as a new vector layer.

12.6.1 Query

Open the Query Builder by opening the Layer Properties and going to the General menu. Under Feature subset, click on the [Query Builder] button to open the Query builder. For example, if you have a regions layer with a

TYPE_2 field, you could select only regions that are borough in the Provider specific filter expression box of the

Query Builder.

Figure_attributes_2

shows an example of the Query Builder populated with the regions.shp

layer from the QGIS sample data. The Fields, Values and Operators sections help you to construct the SQL-like query.

Kuva 12.49: Query Builder

The Fields list contains all attribute columns of the attribute table to be searched. To add an attribute column to

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the SQL WHERE clause field, double click its name in the Fields list. Generally, you can use the various fields, values and operators to construct the query, or you can just type it into the SQL box.

The Values list lists the values of an attribute table. To list all possible values of an attribute, select the attribute in the Fields list and click the [all] button. To list the first 25 unique values of an attribute column, select the attribute column in the Fields list and click the [Sample] button. To add a value to the SQL WHERE clause field, double click its name in the Values list.

The Operators section contains all usable operators. To add an operator to the SQL WHERE clause field, click the appropriate button. Relational operators ( = , > , ...), string comparison operator (LIKE), and logical operators

(AND, OR, ...) are available.

The [Test] button shows a message box with the number of features satisfying the current query, which is useful in the process of query construction. The [Clear] button clears the text in the SQL WHERE clause text field.

The [OK] button closes the window and selects the features satisfying the query. The [Cancel] button closes the window without changing the current selection.

QGIS treats the resulting subset acts as if it where the entire layer. For example if you applied the filter above for

‘Borough’, you can not display, query, save or edit Ankorage, because that is a ‘Manicpality’ and therefore not part of the subset.

.

The only exception is that unless your layer is part of a database, using a subset will prevent you from editing the layer.

12.7 Field Calculator

The

Field Calculator button in the attribute table allows you to perform calculations on the basis of existing attribute values or defined functions, for instance, to calculate length or area of geometry features. The results can be written to a new attribute field, a virtual field, or they can be used to update values in an existing field.

Vihje: Virtual Fields

• Virtual fields are not permanent and are not saved.

• To make a field virtual it must be done when the field is made.

The field calculator is now available on any layer that supports edit. When you click on the field calculator icon the dialog opens (see

figure_attributes_3 ). If the layer is not in edit mode, a warning is displayed and using the

field calculator will cause the layer to be put in edit mode before the calculation is made.

The quick field calculation bar in top of the attribute table is only visible if the layer is editable.

In quick field calculation bar, you first select the existing field name then open the expression dialog to create your expression or write it directly in the field then click on Update All button.

In the field calculator dialog, you first must select whether you want to only update selected features, create a new attribute field where the results of the calculation will be added or update an existing field.

If you choose to add a new field, you need to enter a field name, a field type (integer, real or string), the total field width, and the field precision (see

figure_attributes_3 ). For example, if you choose a field width of 10 and a field

precision of 3, it means you have 6 digits before the dot, then the dot and another 3 digits for the precision.

A short example illustrates how the field calculator works. We want to calculate the length in km of the railroads layer from the QGIS sample dataset:

1. Load the shapefile railroads.shp in QGIS and press

2. Click on

3. Select the

Toggle editing mode and open the

Field Calculator

Open Attribute Table dialog.

.

Create a new field checkbox to save the calculations into a new field.

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4. Add length as Output field name and real as Output field type, and define Output field width to be 10 and Precision, 3.

5. Now double click on function $length in the Geometry group to add it into the Field calculator expression box.

6. Complete the expression by typing ‘’/ 1000” in the Field calculator expression box and click [Ok].

.

7. You can now find a new field length in the attribute table.

The available functions are listed in

Expressions

chapter.

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Working with Raster Data

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13.1 Working with Raster Data

This section describes how to visualize and set raster layer properties. QGIS uses the GDAL library to read and write raster data formats, including ArcInfo Binary Grid, ArcInfo ASCII Grid, GeoTIFF, ERDAS IMAGINE, and many more. GRASS raster support is supplied by a native QGIS data provider plugin. The raster data can also be loaded in read mode from zip and gzip archives into QGIS.

As of the date of this document, more than 100 raster formats are supported by the GDAL library (see GDAL-SOFTWARE-SUITE in

Literature and Web References ). A complete list is available at

http://www.gdal.org/formats_list.html

.

Muista: Not all of the listed formats may work in QGIS for various reasons. For example, some require external commercial libraries, or the GDAL installation of your OS may not have been built to support the format you want to use. Only those formats that have been well tested will appear in the list of file types when loading a raster into

QGIS. Other untested formats can be loaded by selecting the [GDAL] All files (*) filter.

Working with GRASS raster data is described in section

GRASS GIS Integration .

13.1.1 What is raster data?

Raster data in GIS are matrices of discrete cells that represent features on, above or below the earth’s surface. Each cell in the raster grid is the same size, and cells are usually rectangular (in QGIS they will always be rectangular).

Typical raster datasets include remote sensing data, such as aerial photography, or satellite imagery and modelled data, such as an elevation matrix.

Unlike vector data, raster data typically do not have an associated database record for each cell. They are geocoded by pixel resolution and the x/y coordinate of a corner pixel of the raster layer. This allows QGIS to position the data correctly in the map canvas.

QGIS makes use of georeference information inside the raster layer (e.g., GeoTiff) or in an appropriate world file to properly display the data.

13.1.2 Loading raster data in QGIS

Raster layers are loaded either by clicking on the

Add Raster Layer icon or by selecting the Layer → Add

Raster Layer menu option. More than one layer can be loaded at the same time by holding down the Ctrl or

Shift key and clicking on multiple items in the Open a GDAL Supported Raster Data Source dialog.

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Once a raster layer is loaded in the map legend, you can click on the layer name with the right mouse button to select and activate layer-specific features or to open a dialog to set raster properties for the layer.

Right mouse button menu for raster layers

• Zoom to Layer Extent

• Zoom to Best Scale (100%)

• Stretch Using Current Extend

• Show in Overview

• Remove

• Duplicate

• Set Layer CRS

• Set Project CRS from Layer

• Save as ...

• Properties

• Rename

• Copy Style

• Add New Group

• Expand all

• Collapse all

• Update Drawing Order

13.2 Raster Properties Dialog

To view and set the properties for a raster layer, double click on the layer name in the map legend, or right click on the layer name and choose Properties from the context menu. This will open the Raster Layer Properties dialog

(see

figure_raster_1 ).

There are several menus in the dialog:

• General

• Style

• Transparency

• Pyramids

• Histogram

• Metadata

13.2.1 General Menu

Layer Info

The General menu displays basic information about the selected raster, including the layer source path, the display name in the legend (which can be modified), and the number of columns, rows and no-data values of the raster.

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Coordinate reference system

Here, you find the coordinate reference system (CRS) information printed as a PROJ.4 string. If this setting is not correct, it can be modified by clicking the [Specify] button.

Scale Dependent visibility

Additionally scale-dependent visibility can be set in this tab. You will need to check the checkbox and set an appropriate scale where your data will be displayed in the map canvas.

At the bottom, you can see a thumbnail of the layer, its legend symbol, and the palette.

13.2.2 Style Menu

Band rendering

QGIS offers four different Render types. The renderer chosen is dependent on the data type.

1. Multiband color - if the file comes as a multiband with several bands (e.g., used with a satellite image with several bands)

2. Paletted - if a single band file comes with an indexed palette (e.g., used with a digital topographic map)

3. Singleband gray - (one band of) the image will be rendered as gray; QGIS will choose this renderer if the file has neither multibands nor an indexed palette nor a continous palette (e.g., used with a shaded relief map)

4. Singleband pseudocolor - this renderer is possible for files with a continuous palette, or color map (e.g., used with an elevation map)

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Multiband color

With the multiband color renderer, three selected bands from the image will be rendered, each band representing the red, green or blue component that will be used to create a color image. You can choose several Contrast enhancement methods: ‘No enhancement’, ‘Stretch to MinMax’, ‘Stretch and clip to MinMax’ and ‘Clip to min max’.

Kuva 13.2: Raster Renderer - Multiband color

This selection offers you a wide range of options to modify the appearance of your raster layer. First of all, you have to get the data range from your image. This can be done by choosing the Extent and pressing [Load]. QGIS can Estimate (faster) the Min and Max values of the bands or use the Actual (slower) Accuracy .

Now you can scale the colors with the help of the Load min/max values section. A lot of images have a few very low and high data. These outliers can be eliminated using the Cumulative count cut setting. The standard data range is set from 2% to 98% of the data values and can be adapted manually. With this setting, the gray character of the image can disappear. With the scaling option Min/max , QGIS creates a color table with all of the data included in the original image (e.g., QGIS creates a color table with 256 values, given the fact that you have 8 bit bands). You can also calculate your color table using the Mean +/- standard deviation x . Then, only the values within the standard deviation or within multiple standard deviations are considered for the color table. This is useful when you have one or two cells with abnormally high values in a raster grid that are having a negative impact on the rendering of the raster.

All calculations can also be made for the Current extent.

Vihje: Viewing a Single Band of a Multiband Raster

If you want to view a single band of a multiband image (for example, Red), you might think you would set the

Green and Blue bands to “Not Set”. But this is not the correct way. To display the Red band, set the image type to

‘Singleband gray’, then select Red as the band to use for Gray.

Paletted

This is the standard render option for singleband files that already include a color table, where each pixel value is assigned to a certain color. In that case, the palette is rendered automatically. If you want to change colors assigned to certain values, just double-click on the color and the Select color dialog appears. Also, in QGIS 2.2. it’s now possible to assign a label to the color values. The label appears in the legend of the raster layer then.

Contrast enhancement

Muista: When adding GRASS rasters, the option Contrast enhancement will always be set automatically to stretch to min max

, regardless of if this is set to another value in the QGIS general options.

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Singleband gray

This renderer allows you to render a single band layer with a Color gradient: ‘Black to white’ or ‘White to black’.

You can define a Min and a Max value by choosing the Extent first and then pressing [Load]. QGIS can

Estimate (faster) the Min and Max values of the bands or use the Actual (slower) Accuracy .

Kuva 13.4: Raster Renderer - Singleband gray

With the Load min/max values section, scaling of the color table is possible. Outliers can be eliminated using the

Cumulative count cut setting. The standard data range is set from 2% to 98% of the data values and can be adapted manually. With this setting, the gray character of the image can disappear. Further settings can be made with Min/max and Mean +/- standard deviation x . While the first one creates a color table with all of the data included in the original image, the second creates a color table that only considers values within the standard deviation or within multiple standard deviations. This is useful when you have one or two cells with abnormally high values in a raster grid that are having a negative impact on the rendering of the raster.

Singleband pseudocolor

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This is a render option for single-band files, including a continous palette. You can also create individual color maps for the single bands here.

Three types of color interpolation are available:

Kuva 13.5: Raster Renderer - Singleband pseudocolor

1. Discrete

2. Linear

3. Exact

In the left block, the button

Add values manually adds a value to the individual color table. The button

Remove selected row deletes a value from the individual color table, and the

Sort colormap items button sorts the color table according to the pixel values in the value column. Double clicking on the value column lets you insert a specific value. Double clicking on the color column opens the dialog Change color, where you can select a color to apply on that value. Further, you can also add labels for each color, but this value won’t be displayed when you use the identify feature tool. You can also click on the button from the band (if it has any). And you can use the buttons

Load color map from band

, which tries to load the table

Load color map from file an existing color table or to save the defined color table for other sessions.

or

Export color map to file to load

In the right block, Generate new color map allows you to create newly categorized color maps. For the Classification mode ‘Equal interval’, you only need to select the number of classes and press the button

Classify . You can invert the colors of the color map by clicking the Invert checkbox. In the case of the Mode

‘Continous’, QGIS creates classes automatically depending on the Min and Max. Defining Min/Max values can be done with the help of the Load min/max values section. A lot of images have a few very low and high data.

These outliers can be eliminated using the Cumulative count cut setting. The standard data range is set from

2% to 98% of the data values and can be adapted manually. With this setting, the gray character of the image can disappear. With the scaling option Min/max , QGIS creates a color table with all of the data included in the

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original image (e.g., QGIS creates a color table with 256 values, given the fact that you have 8 bit bands). You can also calculate your color table using the Mean +/- standard deviation x . Then, only the values within the standard deviation or within multiple standard deviations are considered for the color table.

Color rendering

For every Band rendering, a Color rendering is possible.

You can also achieve special rendering effects for your raster file(s) using one of the blending modes (see

The

Vector Properties Dialog ).

Further settings can be made in modifiying the Brightness, the Saturation and the Contrast. You can also use a

Grayscale option, where you can choose between ‘By lightness’, ‘By luminosity’ and ‘By average’. For one hue in the color table, you can modify the ‘Strength’.

Resampling

The Resampling option makes its appearance when you zoom in and out of an image. Resampling modes can optimize the appearance of the map. They calculate a new gray value matrix through a geometric transformation.

Kuva 13.6: Raster Rendering - Resampling

When applying the ‘Nearest neighbour’ method, the map can have a pixelated structure when zooming in. This appearance can be improved by using the ‘Bilinear’ or ‘Cubic’ method, which cause sharp features to be blurred.

The effect is a smoother image. This method can be applied, for instance, to digital topographic raster maps.

13.2.3 Transparency Menu

QGIS has the ability to display each raster layer at a different transparency level. Use the transparency slider to indicate to what extent the underlying layers (if any) should be visible though the current raster layer. This is very useful if you like to overlay more than one raster layer (e.g., a shaded relief map overlayed by a classified raster map). This will make the look of the map more three dimensional.

Additionally, you can enter a raster value that should be treated as NODATA in the Additional no data value menu.

An even more flexible way to customize the transparency can be done in the Custom transparency options section.

The transparency of every pixel can be set here.

As an example, we want to set the water of our example raster file landcover.tif to a transparency of 20%.

The following steps are neccessary:

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1. Load the raster file landcover.tif.

2. Open the Properties dialog by double-clicking on the raster name in the legend, or by right-clicking and choosing Properties from the pop-up menu.

3. Select the Transparency menu.

4. From the Transparency band menu, choose ‘None’.

5. Click the

Add values manually button. A new row will appear in the pixel list.

6. Enter the raster value in the ‘From’ and ‘To’ column (we use 0 here), and adjust the transparency to 20%.

7. Press the [Apply] button and have a look at the map.

You can repeat steps 5 and 6 to adjust more values with custom transparency.

As you can see, it is quite easy to set custom transparency, but it can be quite a lot of work. Therefore, you can use the button

Export to file to save your transparency list to a file. The button settings and applies them to the current raster layer.

Import from file loads your transparency

13.2.4 Pyramids Menu

Large resolution raster layers can slow navigation in QGIS. By creating lower resolution copies of the data (pyramids), performance can be considerably improved, as QGIS selects the most suitable resolution to use depending on the level of zoom.

You must have write access in the directory where the original data is stored to build pyramids.

Several resampling methods can be used to calculate the pyramids:

• Nearest Neighbour

• Average

• Gauss

• Cubic

• Mode

• None

If you choose ‘Internal (if possible)’ from the Overview format menu, QGIS tries to build pyramids internally.

You can also choose ‘External’ and ‘External (Erdas Imagine)’.

Please note that building pyramids may alter the original data file, and once created they cannot be removed. If you wish to preserve a ‘non-pyramided’ version of your raster, make a backup copy prior to building pyramids.

13.2.5 Histogram Menu

The Histogram menu allows you to view the distribution of the bands or colors in your raster. The histogram is generated automatically when you open the Histogram menu. All existing bands will be displayed together. You can save the histogram as an image with the button. With the Visibility option in the Prefs/Actions menu, you can display histograms of the individual bands. You will need to select the option

Show selected band

.

The Min/max options allow you to ‘Always show min/max markers’, to ‘Zoom to min/max’ and to ‘Update style to min/max’. With the Actions option, you can ‘Reset’ and ‘Recompute histogram’ after you have chosen the

Min/max options .

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13.2.6 Metadata Menu

The Metadata menu displays a wealth of information about the raster layer, including statistics about each band in the current raster layer. From this menu, entries may be made for the Description, Attribution, MetadataUrl and

Properties . In Properties, statistics are gathered on a ‘need to know’ basis, so it may well be that a given layer’s statistics have not yet been collected.

Kuva 13.9: Raster Metadata

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13.3 Raster Calculator

The Raster Calculator in the Raster menu allows you to perform calculations on the basis of existing raster pixel values (see

figure_raster_10 ). The results are written to a new raster layer with a GDAL-supported format.

The Raster bands list contains all loaded raster layers that can be used. To add a raster to the raster calculator expression field, double click its name in the Fields list. You can then use the operators to construct calculation expressions, or you can just type them into the box.

In the Result layer section, you will need to define an output layer. You can then define the extent of the calculation area based on an input raster layer, or based on X,Y coordinates and on columns and rows, to set the resolution of the output layer. If the input layer has a different resolution, the values will be resampled with the nearest neighbor algorithm.

The Operators section contains all available operators. To add an operator to the raster calculator expression box, click the appropriate button. Mathematical calculations (+, -, *, ... ) and trigonometric functions (sin, cos, tan,

... ) are available. Stay tuned for more operators to come!

With the Add result to project checkbox, the result layer will automatically be added to the legend area and can be visualized.

13.3.1 Examples

Convert elevation values from meters to feet

Creating an elevation raster in feet from a raster in meters, you need to use the conversion factor for meters to feet:

3.28. The expression is:

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"[email protected]"

*

3.28

Using a mask

If you want to mask out parts of a raster – say, for instance, because you are only interested in elevations above 0 meters – you can use the following expression to create a mask and apply the result to a raster in one step.

( "[email protected]" >= 0 )

*

"[email protected]"

In other words, for every cell greater than or equal to 0, set its value to 1. Otherwise set it to 0. This creates the mask on the fly.

If you want to classify a raster – say, for instance into two elevation classes, you can use the following expression to create a raster with two values 1 and 2 in one step.

( "[email protected]" < 50 )

*

1 + ( "[email protected]" >= 50 )

*

2

.

In other words, for every cell less than 50 set its value to 1. For every cell greater than or equal 50 set its value to

2.

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Working with OGC Data

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14.1 QGIS as OGC Data Client

The Open Geospatial Consortium (OGC) is an international organization with membership of more than 300 commercial, governmental, nonprofit and research organizations worldwide. Its members develop and implement standards for geospatial content and services, GIS data processing and exchange.

Describing a basic data model for geographic features, an increasing number of specifications are developed by OGC to serve specific needs for interoperable location and geospatial technology, including GIS. Further information can be found at http://www.opengeospatial.org/ .

Important OGC specifications supported by QGIS are:

• WMS — Web Map Service ( WMS/WMTS Client )

• WMTS — Web Map Tile Service ( WMS/WMTS Client )

• WFS — Web Feature Service ( WFS and WFS-T Client )

• WFS-T — Web Feature Service - Transactional ( WFS and WFS-T Client )

• WCS — Web Coverage Service (

WCS Client

)

• SFS — Simple Features for SQL (

PostGIS Layers

)

• GML — Geography Markup Language

OGC services are increasingly being used to exchange geospatial data between different GIS implementations and data stores. QGIS can deal with the above specifications as a client, being SFS (through support of the PostgreSQL

/ PostGIS data provider, see section

PostGIS Layers ).

14.1.1 WMS/WMTS Client

Overview of WMS Support

QGIS currently can act as a WMS client that understands WMS 1.1, 1.1.1 and 1.3 servers. In particular, it has been tested against publicly accessible servers such as DEMIS.

A WMS server acts upon requests by the client (e.g., QGIS) for a raster map with a given extent, set of layers, symbolization style, and transparency. The WMS server then consults its local data sources, rasterizes the map, and sends it back to the client in a raster format. For QGIS, this format would typically be JPEG or PNG.

WMS is generically a REST (Representational State Transfer) service rather than a full-blown Web service. As such, you can actually take the URLs generated by QGIS and use them in a web browser to retrieve the same images that QGIS uses internally. This can be useful for troubleshooting, as there are several brands of WMS server on the market and they all have their own interpretation of the WMS standard.

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WMS layers can be added quite simply, as long as you know the URL to access the WMS server, you have a serviceable connection to that server, and the server understands HTTP as the data transport mechanism.

Overview of WMTS Support

QGIS can also act as a WMTS client. WMTS is an OGC standard for distributing tile sets of geospatial data.

This is a faster and more efficient way of distributing data than WMS because with WMTS, the tile sets are pregenerated, and the client only requests the transmission of the tiles, not their production. A WMS request typically involves both the generation and transmission of the data. A well-known example of a non-OGC standard for viewing tiled geospatial data is Google Maps.

In order to display the data at a variety of scales close to what the user might want, the WMTS tile sets are produced at several different scale levels and are made available for the GIS client to request them.

This diagram illustrates the concept of tile sets:

Kuva 14.1: Concept of WMTS tile sets

The two types of WMTS interfaces that QGIS supports are via Key-Value-Pairs (KVP) and RESTful. These two interfaces are different, and you need to specify them to QGIS differently.

1) In order to access a WMTS KVP service, a QGIS user must open the WMS/WMTS interface and add the following string to the URL of the WMTS tile service:

"?SERVICE=WMTS&REQUEST=GetCapabilities"

An example of this type of address is http://opencache.statkart.no/gatekeeper/gk/gk.open_wmts?\ service=WMTS&request=GetCapabilities

For testing the topo2 layer in this WMTS works nicely. Adding this string indicates that a WMTS web service is to be used instead of a WMS service.

2. The RESTful WMTS service takes a different form, a straightforward URL. The format recommended by the OGC is:

{WMTSBaseURL}/1.0.0/WMTSCapabilities.xml

This format helps you to recognize that it is a RESTful address. A RESTful WMTS is accessed in QGIS by simply adding its address in the WMS setup in the URL field of the form. An example of this type of address for the case of an Austrian basemap is http://maps.wien.gv.at/basemap/1.0.0/WMTSCapabilities.xml

.

Muista: You can still find some old services called WMS-C. These services are quite similar to WMTS (i.e., same purpose but working a little bit differently). You can manage them the same as you do WMTS services.

Just add ?tiled=true at the end of the url. See http://wiki.osgeo.org/wiki/Tile_Map_Service_Specification for more information about this specification.

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When you read WMTS, you can often think WMS-C also.

Selecting WMS/WMTS Servers

The first time you use the WMS feature in QGIS, there are no servers defined.

Begin by clicking the

Add WMS layer button on the toolbar, or selecting Layer → Add WMS Layer....

The dialog Add Layer(s) from a Server for adding layers from the WMS server appears. You can add some servers to play with by clicking the [Add default servers] button. This will add two WMS demo servers for you to use: the

WMS servers of the DM Solutions Group and Lizardtech. To define a new WMS server in the Layers tab, select the [New] button. Then enter the parameters to connect to your desired WMS server, as listed in

table_OGC_1 :

Name A name for this connection. This name will be used in the Server Connections drop-down

URL

Username

Password box so that you can distinguish it from other WMS servers.

URL of the server providing the data. This must be a resolvable host name – the same format as you would use to open a telnet connection or ping a host.

Username to access a secured WMS server. This parameter is optional.

Password for a basic authenticated WMS server. This parameter is optional.

Ignore GetMap URI reported in capabilities . Use given URI from URL field above.

Ignore GetMap

URI

Ignore

GetFeatureInfo

URI

Ignore GetFeatureInfo URI reported in capabilities above.

. Use given URI from URL field

Table OGC 1: WMS Connection Parameters

If you need to set up a proxy server to be able to receive WMS services from the internet, you can add your proxy server in the options. Choose Settings → Options and click on the Network & Proxy tab. There, you can add your proxy settings and enable them by setting proxy type from the Proxy type

Use proxy for web access drop-down menu.

. Make sure that you select the correct

Once the new WMS server connection has been created, it will be preserved for future QGIS sessions.

Vihje: On WMS Server URLs

Be sure, when entering the WMS server URL, that you have the base URL only. For example, you shouldn’t have fragments such as request=GetCapabilities or version=1.0.0 in your URL.

Loading WMS/WMTS Layers

Once you have successfully filled in your parameters, you can use the [Connect] button to retrieve the capabilities of the selected server. This includes the image encoding, layers, layer styles and projections. Since this is a network operation, the speed of the response depends on the quality of your network connection to the WMS server. While downloading data from the WMS server, the download progress is visualized in the lower left of the WMS dialog.

Your screen should now look a bit like

figure_OGR_1 , which shows the response provided by the DM Solutions

Group WMS server.

Image Encoding

The Image encoding section lists the formats that are supported by both the client and server. Choose one depending on your image accuracy requirements.

Vihje: Image Encoding

You will typically find that a WMS server offers you the choice of JPEG or PNG image encoding. JPEG is a lossy compression format, whereas PNG faithfully reproduces the raw raster data.

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Use JPEG if you expect the WMS data to be photographic in nature and/or you don’t mind some loss in picture quality. This trade-off typically reduces by five times the data transfer requirement compared with PNG.

Use PNG if you want precise representations of the original data and you don’t mind the increased data transfer requirements.

Options

The Options area of the dialog provides a text field where you can add a Layer name for the WMS layer. This name will appear in the legend after loading the layer.

Below the layer name, you can define Tile size if you want to set tile sizes (e.g., 256x256) to split up the WMS request into multiple requests.

The Feature limit for GetFeatureInfo defines what features from the server to query.

If you select a WMS from the list, a field with the default projection provided by the mapserver appears. If the

[Change...] button is active, you can click on it and change the default projection of the WMS to another CRS provided by the WMS server.

Layer Order

The Layer Order tab lists the selected layers available from the current connected WMS server. You may notice that some layers are expandable; this means that the layer can be displayed in a choice of image styles.

You can select several layers at once, but only one image style per layer. When several layers are selected, they will be combined at the WMS server and transmitted to QGIS in one go.

Vihje: WMS Layer Ordering

WMS layers rendered by a server are overlaid in the order listed in the Layers section, from top to bottom of the list. If you want to change the overlay order, you can use the Layer Order tab.

Transparency

In this version of QGIS, the Global transparency setting from the Layer Properties is hard coded to be always on, where available.

Vihje: WMS Layer Transparency

The availability of WMS image transparency depends on the image encoding used: PNG and GIF support transparency, whilst JPEG leaves it unsupported.

Coordinate Reference System

A coordinate reference system (CRS) is the OGC terminology for a QGIS projection.

Each WMS layer can be presented in multiple CRSs, depending on the capability of the WMS server.

To choose a CRS, select [Change...] and a dialog similar to Figure Projection 3 in

Working with Projections

will appear. The main difference with the WMS version of the dialog is that only those CRSs supported by the WMS server will be shown.

Server search

Within QGIS, you can search for WMS servers.

Figure_OGC_2

shows the Server Search tab with the Add Layer(s) from a Server dialog.

As you can see, it is possible to enter a search string in the text field and hit the [Search] button. After a short while, the search result will be populated into the list below the text field. Browse the result list and inspect your search results within the table. To visualize the results, select a table entry, press the [Add selected row to WMS list] button and change back to the Layers tab. QGIS has automatically updated your server list, and the selected search result is already enabled in the list of saved WMS servers in the Layers tab. You only need to request the list

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Kuva 14.3: Dialog for searching WMS servers after some keywords of layers by clicking the [Connect] button. This option is quite handy when you want to search maps by specific keywords.

Basically, this option is a front end to the API of http://geopole.org

.

Tilesets

When using WMTS (Cached WMS) services like http://opencache.statkart.no/gatekeeper/gk/gk.open_wmts?\ service=WMTS&request=GetCapabilities you are able to browse through the Tilesets tab given by the server. Additional information like tile size, formats and supported CRS are listed in this table. In combination with this feature, you can use the tile scale slider by selecting Settings → Panels (KDE and Windows) or View → Panels (Gnome and MacOSX), then choosing Tile scale . This gives you the available scales from the tile server with a nice slider docked in.

Using the Identify Tool

Once you have added a WMS server, and if any layer from a WMS server is queryable, you can then use the

Identify tool to select a pixel on the map canvas. A query is made to the WMS server for each selection made. The results of the query are returned in plain text. The formatting of this text is dependent on the particular WMS server used. Format selection

If multiple output formats are supported by the server, a combo box with supported formats is automatically added to the identify results dialog and the selected format may be stored in the project for the layer. GML format support

The

Identify tool supports WMS server response (GetFeatureInfo) in GML format (it is called Feature in the

QGIS GUI in this context). If “Feature” format is supported by the server and selected, results of the Identify tool

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are vector features, as from a regular vector layer. When a single feature is selected in the tree, it is highlighted in the map and it can be copied to the clipboard and pasted to another vector layer. See the example setup of the

UMN Mapserver below to support GetFeatureInfo in GML format.

# in layer METADATA add which fields should be included and define geometry (example):

"gml_include_items"

"ows_geometries"

"ows_mygeom_type"

"all"

"mygeom"

"polygon"

# Then there are two possibilities/formats available, see a) and b):

# a) basic (output is generated by Mapserver and does not contain XSD)

# in WEB METADATA define formats (example):

"wms_getfeatureinfo_formatlist" "application/vnd.ogc.gml,text/html"

# b) using OGR (output is generated by OGR, it is send as multipart and contains XSD)

# in MAP define OUTPUTFORMAT (example):

OUTPUTFORMAT

NAME "OGRGML"

MIMETYPE "ogr/gml"

DRIVER "OGR/GML"

FORMATOPTION "FORM=multipart"

END

# in WEB METADATA define formats (example):

"wms_getfeatureinfo_formatlist" "OGRGML,text/html"

Viewing Properties

Once you have added a WMS server, you can view its properties by right-clicking on it in the legend and selecting

Properties . Metadata Tab

The tab Metadata displays a wealth of information about the WMS server, generally collected from the capabilities statement returned from that server. Many definitions can be gleaned by reading the WMS standards (see OPEN-

GEOSPATIAL-CONSORTIUM in

Literature and Web References ), but here are a few handy definitions:

• Server Properties

– WMS Version — The WMS version supported by the server.

– Image Formats — The list of MIME-types the server can respond with when drawing the map.

QGIS supports whatever formats the underlying Qt libraries were built with, which is typically at least image/png and image/jpeg.

– Identity Formats — The list of MIME-types the server can respond with when you use the Identify tool. Currently, QGIS supports the text-plain type.

• Layer Properties

– Selected — Whether or not this layer was selected when its server was added to this project.

– Visible — Whether or not this layer is selected as visible in the legend (not yet used in this version of

QGIS).

– Can Identify — Whether or not this layer will return any results when the Identify tool is used on it.

– Can be Transparent — Whether or not this layer can be rendered with transparency. This version of

QGIS will always use transparency if this is Yes and the image encoding supports transparency.

– Can Zoom In — Whether or not this layer can be zoomed in by the server. This version of QGIS assumes all WMS layers have this set to Yes. Deficient layers may be rendered strangely.

– Cascade Count — WMS servers can act as a proxy to other WMS servers to get the raster data for a layer. This entry shows how many times the request for this layer is forwarded to peer WMS servers for a result.

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– Fixed Width, Fixed Height — Whether or not this layer has fixed source pixel dimensions. This version of QGIS assumes all WMS layers have this set to nothing. Deficient layers may be rendered strangely.

– WGS 84 Bounding Box — The bounding box of the layer, in WGS 84 coordinates. Some WMS servers do not set this correctly (e.g., UTM coordinates are used instead). If this is the case, then the initial view of this layer may be rendered with a very ‘zoomed-out’ appearance by QGIS. The

WMS webmaster should be informed of this error, which they may know as the WMS XML elements

LatLonBoundingBox

, EX_GeographicBoundingBox or the CRS:84 BoundingBox.

– Available in CRS — The projections that this layer can be rendered in by the WMS server. These are listed in the WMS-native format.

– Available in style — The image styles that this layer can be rendered in by the WMS server.

Show WMS legend graphic in table of contents and composer

The QGIS WMS data provider is able to display a legend graphic in the table of contents’ layer list and in the map composer. The WMS legend will be shown only if the WMS server has GetLegendGraphic capability and the layer has getCapability url specified, so you additionally have to select a styling for the layer.

If a legendGraphic is available, it is shown below the layer. It is little and you have to click on it to open it in real dimension (due to QgsLegendInterface architectural limitation). Clicking on the layer’s legend will open a frame with the legend at full resolution.

In the print composer, the legend will be integrated at it’s original (dowloaded) dimension. Resolution of the legend graphic can be set in the item properties under Legend -> WMS LegendGraphic to match your printing requirements

The legend will display contextual information based on your current scale. The WMS legend will be shown only if the WMS server has GetLegendGraphic capability and the layer has getCapability url specified, so you have to select a styling.

WMS Client Limitations

Not all possible WMS client functionality had been included in this version of QGIS. Some of the more noteworthy exceptions follow.

Editing WMS Layer Settings

Once you’ve completed the

Add WMS layer to delete the layer completely and start again.

procedure, there is no way to change the settings. A work-around is

WMS Servers Requiring Authentication

Currently, publicly accessible and secured WMS services are supported. The secured WMS servers can be accessed by public authentication. You can add the (optional) credentials when you add a WMS server. See section

Selecting WMS/WMTS Servers

for details.

Vihje: Accessing secured OGC-layers

If you need to access secured layers with secured methods other than basic authentication, you can use InteProxy as a transparent proxy, which does support several authentication methods. More information can be found in the

InteProxy manual at http://inteproxy.wald.intevation.org

.

Vihje: QGIS WMS Mapserver

Since Version 1.7.0, QGIS has its own implementation of a WMS 1.3.0 Mapserver. Read more about this in chapter

QGIS as OGC Data Server

.

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14.1.2 WCS Client

A Web Coverage Service (WCS) provides access to raster data in forms that are useful for client-side rendering, as input into scientific models, and for other clients. The WCS may be compared to the WFS and the WMS.

As WMS and WFS service instances, a WCS allows clients to choose portions of a server’s information holdings based on spatial constraints and other query criteria.

QGIS has a native WCS provider and supports both version 1.0 and 1.1 (which are significantly different), but currently it prefers 1.0, because 1.1 has many issues (i.e., each server implements it in a different way with various particularities).

The native WCS provider handles all network requests and uses all standard QGIS network settings (especially proxy). It is also possible to select cache mode (‘always cache’, ‘prefer cache’, ‘prefer network’, ‘always network’), and the provider also supports selection of time position, if temporal domain is offered by the server.

.

14.1.3 WFS and WFS-T Client

In QGIS, a WFS layer behaves pretty much like any other vector layer. You can identify and select features, and view the attribute table. Since QGIS 1.6, editing WFS-T is also supported.

In general, adding a WFS layer is very similar to the procedure used with WMS. The difference is that there are no default servers defined, so we have to add our own.

Loading a WFS Layer

As an example, we use the DM Solutions WFS server and display a layer.

The URL is: http://www2.dmsolutions.ca/cgi-bin/mswfs_gmap

1. Click on the

2. Click on [New].

Add WFS Layer tool on the Layers toolbar. The Add WFS Layer from a Server dialog appears.

3. Enter ‘DM Solutions’ as name.

4. Enter the URL (see above).

5. Click [OK].

6. Choose ‘DM Solutions’ from the Server Connections

7. Click [Connect].

8. Wait for the list of layers to be populated.

9. Select the Parks layer in the list.

drop-down list.

10. Click [Apply] to add the layer to the map.

Note that any proxy settings you may have set in your preferences are also recognized.

You’ll notice the download progress is visualized in the lower left of the QGIS main window. Once the layer is loaded, you can identify and select a province or two and view the attribute table.

Only WFS 1.0.0 is supported. At this time, there have not been many tests against WFS versions implemented in other WFS servers. If you encounter problems with any other WFS server, please do not hesitate to contact the development team. Please refer to section

Help and Support

for further information about the mailing lists.

Vihje: Finding WFS Servers

You can find additional WFS servers by using Google or your favorite search engine. There are a number of lists with public URLs, some of them maintained and some not.

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14.2 QGIS as OGC Data Server

QGIS Server is an open source WMS 1.3, WFS 1.0.0 and WCS 1 1.1.1 implementation that, in addition, implements advanced cartographic features for thematic mapping. The QGIS Server is a FastCGI/CGI (Common

Gateway Interface) application written in C++ that works together with a web server (e.g., Apache, Lighttpd). It is funded by the EU projects Orchestra, Sany and the city of Uster in Switzerland.

QGIS Server uses QGIS as back end for the GIS logic and for map rendering. Furthermore, the Qt library is used for graphics and for platform-independent C++ programming. In contrast to other WMS software, the QGIS

Server uses cartographic rules as a configuration language, both for the server configuration and for the userdefined cartographic rules.

As QGIS desktop and QGIS Server use the same visualization libraries, the maps that are published on the web look the same as in desktop GIS.

In one of the following manuals, we will provide a sample configuration to set up a QGIS Server. For now, we recommend to read one of the following URLs to get more information:

• http://karlinapp.ethz.ch/qgis_wms/

• http://hub.qgis.org/projects/quantum-gis/wiki/QGIS_Server_Tutorial

• http://linfiniti.com/2010/08/qgis-mapserver-a-wms-server-for-the-masses/

14.2.1 Sample installation on Debian Squeeze

At this point, we will give a short and simple sample installation how-to for Debian Squeeze. Many other OSs provide packages for QGIS Server, too. If you have to build it all from source, please refer to the URLs above.

Apart from QGIS and QGIS Server, you need a web server, in our case apache2. You can install all packages with aptitude or apt-get install together with other necessary dependency packages. After installation, you should test to confirm that the web server and QGIS Server work as expected. Make sure the apache server is running with /etc/init.d/apache2 start. Open a web browser and type URL: http://localhost.

If apache is up, you should see the message ‘It works!’.

Now we test the QGIS Server installation.

The qgis_mapserv.fcgi

is available at

/usr/lib/cgi-bin/qgis_mapserv.fcgi

and provides a standard WMS that shows the state boundaries of Alaska. Add the WMS with the URL http://localhost/cgi-bin/qgis_mapserv.fcgi as described in

Selecting WMS/WMTS Servers .

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Kuva 14.5: Standard WMS with USA boundaries included in the QGIS Server (KDE)

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14.2.2 Creating a WMS/WFS/WCS from a QGIS project

To provide a new QGIS Server WMS, WFS or WCS, we have to create a QGIS project file with some data. Here, we use the ‘Alaska’ shapefile from the QGIS sample dataset. Define the colors and styles of the layers in QGIS and the project CRS, if not already defined.

Kuva 14.6: Definitions for a QGIS Server WMS/WFS/WCS project (KDE)

Then, go to the OWS Server menu of the Project → Project Properties dialog and provide some information about the OWS in the fields under Service Capabilities. This will appear in the GetCapabilities response of the WMS,

WFS or WCS. If you don’t check Service capabilities , QGIS Server will use the information given in the wms_metadata.xml

file located in the cgi-bin folder.

WMS capabilities

In the WMS capabilities section, you can define the extent advertised in the WMS GetCapabilities response by entering the minimum and maximum X and Y values in the fields under Advertised extent. Clicking Use Current

Canvas Extent sets these values to the extent currently displayed in the QGIS map canvas. By checking CRS restrictions , you can restrict in which coordinate reference systems (CRS) QGIS Server will offer to render maps.

Use the button below to select those CRS from the Coordinate Reference System Selector, or click Used to add the CRS used in the QGIS project to the list.

If you have print composers defined in your project, they will be listed in the GetCapabilities response, and they can be used by the GetPrint request to create prints, using one of the print composer layouts as a template. This

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is a QGIS-specific extension to the WMS 1.3.0 specification. If you want to exclude any print composer from being published by the WMS, check Exclude composers and click the button below. Then, select a print composer from the Select print composer dialog in order to add it to the excluded composers list.

If you want to exclude any layer or layer group from being published by the WMS, check Exclude Layers and click the button below. This opens the Select restricted layers and groups dialog, which allows you to choose the layers and groups that you don’t want to be published. Use the Shift or Ctrl key if you want to select multiple entries at once.

You can receive requested GetFeatureInfo as plain text, XML and GML. Default is XML, text or GML format depends the output format choosen for the GetFeatureInfo request.

If you wish, you can check Add geometry to feature response . This will include in the GetFeatureInfo response the geometries of the features in a text format. If you want QGIS Server to advertise specific request URLs in the

WMS GetCapabilities response, enter the corresponding URL in the Advertised URL field. Furthermore, you can restrict the maximum size of the maps returned by the GetMap request by entering the maximum width and height into the respective fields under Maximums for GetMap request.

If one of your layers uses the Map Tip display (i.e. to show text using expressions) this will be listed inside the

GetFeatureInfo output. If the layer uses a Value Map for one of his attributes, also this information will be shown in the GetFeatureInfo output.

WFS capabilities

In the WFS capabilities area, you can select the layers that you want to publish as WFS, and specify if they will allow the update, insert and delete operations. If you enter a URL in the Advertised URL field of the WFS capabilities section, QGIS Server will advertise this specific URL in the WFS GetCapabilities response.

WCS capabilities

In the WCS capabilities area, you can select the layers that you want to publish as WCS. If you enter a URL in the

Advertised URL field of the WCS capabilities section, QGIS Server will advertise this specific URL in the WCS

GetCapabilities response.

Now, save the session in a project file alaska.qgs. To provide the project as a WMS/WFS, we create a new folder /usr/lib/cgi-bin/project with admin privileges and add the project file alaska.qgs and a copy of the qgis_mapserv.fcgi file - that’s all.

Now we test our project WMS, WFS and WCS. Add the WMS, WFS and WCS as described in

Loading

WMS/WMTS Layers

,

WFS and WFS-T Client

and

WCS Client

to QGIS and load the data. The URL is: http://localhost/cgi-bin/project/qgis_mapserv.fcgi

Fine tuning your OWS

For vector layers, the Fields menu of the Layer → Properties dialog allows you to define for each attribute if it will be published or not. By default, all the attributes are published by your WMS and WFS. If you want a specific attribute not to be published, uncheck the corresponding checkbox in the WMS or WFS column.

You can overlay watermarks over the maps produced by your WMS by adding text annotations or SVG annotations to the project file. See section Annotation Tools in

General Tools

for instructions on creating annotations. For annotations to be displayed as watermarks on the WMS output, the Fixed map position check box in the Annotation text dialog must be unchecked. This can be accessed by double clicking the annotation while one of the annotation tools is active. For SVG annotations, you will need either to set the project to save absolute paths (in the General menu of the Project → Project Properties dialog) or to manually modify the path to the SVG image in a way that it represents a valid relative path.

Extra parameters supported by the WMS GetMap request

In the WMS GetMap request, QGIS Server accepts a couple of extra parameters in addition to the standard parameters according to the OCG WMS 1.3.0 specification:

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• MAP parameter: Similar to MapServer, the MAP parameter can be used to specify the path to the QGIS project file. You can specify an absolute path or a path relative to the location of the server executable

(qgis_mapserv.fcgi). If not specified, QGIS Server searches for .qgs files in the directory where the server executable is located.

Example: http://localhost/cgi-bin/qgis_mapserv.fcgi?\

REQUEST=GetMap&MAP=/home/qgis/mymap.qgs&...

• DPI parameter: The DPI parameter can be used to specify the requested output resolution.

Example: http://localhost/cgi-bin/qgis_mapserv.fcgi?REQUEST=GetMap&DPI=300&...

• OPACITIES parameter: Opacity can be set on layer or group level. Allowed values range from 0 (fully transparent) to 255 (fully opaque).

Example: http://localhost/cgi-bin/qgis_mapserv.fcgi?\

REQUEST=GetMap&LAYERS=mylayer1,mylayer2&OPACITIES=125,200&...

QGIS Server logging

To log requests send to server, set the following environment variables:

• QGIS_SERVER_LOG_FILE: Specify path and filename. Make sure that server has proper permissions for writing to file. File should be created automatically, just send some requests to server. If it’s not there, check permissions.

• QGIS_SERVER_LOG_LEVEL: Specify desired log level. Available values are:

– 0 INFO (log all requests),

– 1 WARNING,

– 2 CRITICAL (log just critical errors, suitable for production purposes).

Example:

SetEnv QGIS_SERVER_LOG_FILE /var/tmp/qgislog.txt

SetEnv QGIS_SERVER_LOG_LEVEL 0

Note

• When using Fcgid module use FcgidInitialEnv instead of SetEnv!

• Server logging is enabled also if executable is compiled in release mode.

.

Environment variables

• QGIS_OPTIONS_PATH: The variable specifies path to directory with settings.

It works the same ways as QGIS application –optionspath option. It is looking for settings file in

<QGIS_OPTIONS_PATH>/QGIS/QGIS2.ini. For exaple, to set QGIS server on Apache to use

/path/to/config/QGIS/QGIS2.ini settings file, add to Apache config:

SetEnv QGIS_OPTIONS_PATH "/path/to/config/"

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15

Working with GPS Data

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15.1 GPS Plugin

15.1.1 What is GPS?

GPS, the Global Positioning System, is a satellite-based system that allows anyone with a GPS receiver to find their exact position anywhere in the world. GPS is used as an aid in navigation, for example in airplanes, in boats and by hikers. The GPS receiver uses the signals from the satellites to calculate its latitude, longitude and (sometimes) elevation. Most receivers also have the capability to store locations (known as waypoints), sequences of locations that make up a planned route and a tracklog or track of the receiver’s movement over time. Waypoints, routes and tracks are the three basic feature types in GPS data. QGIS displays waypoints in point layers, while routes and tracks are displayed in linestring layers.

15.1.2 Loading GPS data from a file

There are dozens of different file formats for storing GPS data. The format that QGIS uses is called GPX (GPS eXchange format), which is a standard interchange format that can contain any number of waypoints, routes and tracks in the same file.

To load a GPX file, you first need to load the plugin. Plugins → Plugin Manager...

opens the Plugin Manager

Dialog. Activate the GPS Tools checkbox. When this plugin is loaded, two buttons with a small handheld GPS device will show up in the toolbar:

Create new GPX Layer

GPS Tools

For working with GPS data, we provide an example GPX file available in the QGIS sample dataset: qgis_sample_data/gps/national_monuments.gpx

. See section

Sample Data

for more information about the sample data.

1. Select Vector → GPS → GPS Tools or click the tab (see

figure_GPS_1 ).

GPS Tools icon in the toolbar and open the Load GPX file

2. Browse to the folder qgis_sample_data/gps/, select the GPX file national_monuments.gpx

and click [Open].

Use the [Browse...] button to select the GPX file, then use the checkboxes to select the feature types you want to load from that GPX file. Each feature type will be loaded in a separate layer when you click [OK]. The file national_monuments.gpx

only includes waypoints.

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Muista: GPS units allow you to store data in different coordinate systems. When downloading a GPX file (from your GPS unit or a web site) and then loading it in QGIS, be sure that the data stored in the

GPX file uses WGS 84 (latitude/longitude). QGIS expects this, and it is the official GPX specification. See http://www.topografix.com/GPX/1/1/ .

15.1.3 GPSBabel

Since QGIS uses GPX files, you need a way to convert other GPS file formats to GPX. This can be done for many formats using the free program GPSBabel, which is available at http://www.gpsbabel.org

. This program can also transfer GPS data between your computer and a GPS device. QGIS uses GPSBabel to do these things, so it is recommended that you install it. However, if you just want to load GPS data from GPX files you will not need it.

Version 1.2.3 of GPSBabel is known to work with QGIS, but you should be able to use later versions without any problems.

15.1.4 Importing GPS data

To import GPS data from a file that is not a GPX file, you use the tool Import other file in the GPS Tools dialog.

Here, you select the file that you want to import (and the file type), which feature type you want to import from it, where you want to store the converted GPX file and what the name of the new layer should be. Note that not all

GPS data formats will support all three feature types, so for many formats you will only be able to choose between one or two types.

15.1.5 Downloading GPS data from a device

QGIS can use GPSBabel to download data from a GPS device directly as new vector layers. For this we use the

Download from GPS tab of the GPS Tools dialog (see

Figure_GPS_2 ). Here, we select the type of GPS device,

the port that it is connected to (or USB if your GPS supports this), the feature type that you want to download, the

GPX file where the data should be stored, and the name of the new layer.

The device type you select in the GPS device menu determines how GPSBabel tries to communicate with your

GPS device. If none of the available types work with your GPS device, you can create a new type (see section

Defining new device types ).

The port may be a file name or some other name that your operating system uses as a reference to the physical port in your computer that the GPS device is connected to. It may also be simply USB, for USB-enabled GPS units.

• On Linux, this is something like /dev/ttyS0 or /dev/ttyS1.

• On Windows, it is COM1 or COM2.

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When you click [OK], the data will be downloaded from the device and appear as a layer in QGIS.

15.1.6 Uploading GPS data to a device

You can also upload data directly from a vector layer in QGIS to a GPS device using the Upload to GPS tab of the

GPS Tools dialog. To do this, you simply select the layer that you want to upload (which must be a GPX layer), your GPS device type, and the port (or USB) that it is connected to. Just as with the download tool, you can specify new device types if your device isn’t in the list.

This tool is very useful in combination with the vector-editing capabilities of QGIS. It allows you to load a map, create waypoints and routes, and then upload them and use them on your GPS device.

15.1.7 Defining new device types

There are lots of different types of GPS devices. The QGIS developers can’t test all of them, so if you have one that does not work with any of the device types listed in the Download from GPS and Upload to GPS tools, you can define your own device type for it. You do this by using the GPS device editor, which you start by clicking the

[Edit devices] button in the download or the upload tab.

To define a new device, you simply click the [New device] button, enter a name, enter download and upload commands for your device, and click the [Update device] button. The name will be listed in the device menus in the upload and download windows – it can be any string. The download command is the command that is used to download data from the device to a GPX file. This will probably be a GPSBabel command, but you can use any other command line program that can create a GPX file. QGIS will replace the keywords %type, %in, and %out when it runs the command.

%type will be replaced by -w if you are downloading waypoints, -r if you are downloading routes and -t if you are downloading tracks. These are command-line options that tell GPSBabel which feature type to download.

%in will be replaced by the port name that you choose in the download window and %out will be replaced by the name you choose for the GPX file that the downloaded data should be stored in. So, if you create a device type with the download command gpsbabel %type -i garmin -o gpx %in %out (this is actually the download command for the predefined device type ‘Garmin serial’) and then use it to download waypoints from port /dev/ttyS0 to the file output.gpx, QGIS will replace the keywords and run the command gpsbabel

-w -i garmin -o gpx /dev/ttyS0 output.gpx

.

The upload command is the command that is used to upload data to the device. The same keywords are used, but

%in is now replaced by the name of the GPX file for the layer that is being uploaded, and %out is replaced by the port name.

You can learn more about GPSBabel and its available command line options at http://www.gpsbabel.org

.

Once you have created a new device type, it will appear in the device lists for the download and upload tools.

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15.1.8 Download of points/tracks from GPS units

As described in previous sections QGIS uses GPSBabel to download points/tracks directly in the project. QGIS comes out of the box with a pre-defined profile to download from Garmin devices. Unfortunately there is a bug

#6318 that does not allow create other profiles, so downloading directly in QGIS using the GPS Tools is at the moment limited to Garmin USB units.

Garmin GPSMAP 60cs

MS Windows

Install the Garmin USB drivers from http://www8.garmin.com/support/download_details.jsp?id=591

Connect the unit. Open GPS Tools and use type=garmin serial and port=usb: Fill the fields Layer name and Output file. Sometimes it seems to have problems saving in a certain folder, using something like c:\temp usually works.

Ubuntu/Mint GNU/Linux

It is first needed an issue about the permissions of the device, as described at https://wiki.openstreetmap.org/wiki/USB_Garmin_on_GNU/Linux .

You can try to create a file

/etc/udev/rules.d/51-garmin.rules

containing this rule

ATTRS{idVendor}=="091e", ATTRS{idProduct}=="0003", MODE="666"

After that is necessary to be sure that the garmin_gps kernel module is not loaded rmmod garmin_gps and then you can use the GPS Tools. Unfortunately there seems to be a bug #7182 and usually QGIS freezes several times before the operation work fine.

BTGP-38KM datalogger (only Bluetooth)

MS Windows

The already referred bug does not allow to download the data from within QGIS, so it is needed to use GPSBabel from the command line or using its interface. The working command is gpsbabel -t -i skytraq,baud=9600,initbaud=9600 -f COM9 -o gpx -F C:/GPX/aaa.gpx

Ubuntu/Mint GNU/Linux

Use same command (or settings if you use GPSBabel GUI) as in Windows. On Linux it maybe somehow common to get a message like skytraq: Too many read errors on serial port it is just a matter to turn off and on the datalogger and try again.

BlueMax GPS-4044 datalogger (both BT and USB)

MS Windows

Muista: It needs to install its drivers before using it on Windows 7. See in the manufacturer site for the proper download.

Downloading with GPSBabel, both with USB and BT returns always an error like gpsbabel -t -i mtk -f COM12 -o gpx -F C:/temp/test.gpx

mtk_logger: Can’t create temporary file data.bin

Error running gpsbabel: Process exited unsucessfully with code 1

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With USB

After having connected the cable use the dmesg command to understand what port is being used, for example

/dev/ttyACM3 . Then as usual use GPSBabel from the CLI or GUI gpsbabel -t -i mtk -f /dev/ttyACM3 -o gpx -F /home/user/bluemax.gpx

.

With Bluetooth

Use Blueman Device Manager to pair the device and make it available through a system port, then run GPSBabel gpsbabel -t -i mtk -f /dev/rfcomm0 -o gpx -F /home/user/bluemax_bt.gpx

15.2 Live GPS tracking

To activate live GPS tracking in QGIS, you need to select Settings → Panels new docked window on the left side of the canvas.

There are four possible screens in this GPS tracking window:

GPS position coordinates and an interface for manually entering vertices and features

GPS signal strength of satellite connections

GPS information . You will get a

• GPS polar screen showing number and polar position of satellites

• GPS options screen (see

figure_gps_options )

With a plugged-in GPS receiver (has to be supported by your operating system), a simple click on [Connect] connects the GPS to QGIS. A second click (now on [Disconnect]) disconnects the GPS receiver from your computer.

For GNU/Linux, gpsd support is integrated to support connection to most GPS receivers. Therefore, you first have to configure gpsd properly to connect QGIS to it.

Varoitus: If you want to record your position to the canvas, you have to create a new vector layer first and switch it to editable status to be able to record your track.

15.2.1 Position and additional attributes

If the GPS is receiving signals from satellites, you will see your position in latitude, longitude and altitude together with additional attributes.

15.2.2 GPS signal strength

Here, you can see the signal strength of the satellites you are receiving signals from.

15.2.3 GPS polar window

If you want to know where in the sky all the connected satellites are, you have to switch to the polar screen.

You can also see the ID numbers of the satellites you are receiving signals from.

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15.2.4 GPS options

In case of connection problems, you can switch between:

Autodetect

Internal

Serial device gpsd (selecting the Host, Port and Device your GPS is connected to)

A click on [Connect] again initiates the connection to the GPS receiver.

You can activate Automatically save added features when you are in editing mode. Or you can activate

Automatically add points to the map canvas with a certain width and color.

Activating canvas.

Cursor , you can use a slider to shrink and grow the position cursor on the

Activating Map centering allows you to decide in which way the canvas will be updated. This includes ‘always’, ‘when leaving’, if your recorded coordinates start to move out of the canvas, or ‘never’, to keep map extent.

Finally, you can activate logged.

Log file and define a path and a file where log messages about the GPS tracking are

If you want to set a feature manually, you have to go back to point].

Position and click on [Add Point] or [Add track

15.2.5 Connect to a Bluetooth GPS for live tracking

With QGIS you can connect a Bluetooth GPS for field data collection. To perform this task you need a GPS

Bluetooth device and a Bluetooth receiver on your computer.

At first you must let your GPS device be recognized and paired to the computer. Turn on the GPS, go to the

Bluetooth icon on your notification area and search for a New Device.

On the right side of the Device selection mask make sure that all devices are selected so your GPS unit will probably appear among those available. In the next step a serial connection service should be available, select it and click on [Configure] button.

Remember the number of the COM port assigned to the GPS connection as resulting by the Bluetooth properties.

After the GPS has been recognized, make the pairing for the connection. Usually the autorization code is 0000.

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Now open GPS information panel and switch to GPS options screen. Select the COM port assigned to the GPS connection and click the [Connect]. After a while a cursor indicating your position should appear.

If QGIS can’t receive GPS data, then you should restart your GPS device, wait 5-10 seconds then try to connect again. Usually this solution work. If you receive again a connection error make sure you don’t have another

Bluetooth receiver near you, paired with the same GPS unit.

15.2.6 Using GPSMAP 60cs

MS Windows

Easiest way to make it work is to use a middleware (freeware, not open) called GPSGate .

Launch the program, make it scan for GPS devices (works for both USB and BT ones) and then in QGIS just click

[Connect] in the Live tracking panel using the

Autodetect mode.

Ubuntu/Mint GNU/Linux

As for Windows the easiest way is to use a server in the middle, in this case GPSD, so sudo apt-get install gpsd

Then load the garmin_gps kernel module sudo modprobe garmin_gps

And then connect the unit. Then check with dmesg the actual device being used bu the unit, for example

/dev/ttyUSB0

. Now you can launch gpsd gpsd / dev / ttyUSB0

And finally connect with the QGIS live tracking tool.

15.2.7 Using BTGP-38KM datalogger (only Bluetooth)

Using GPSD (under Linux) or GPSGate (under Windows) is effortless.

15.2.8 Using BlueMax GPS-4044 datalogger (both BT and USB)

MS Windows

The live tracking works for both USB and BT modes, by using GPSGate or even without it, just use the

Autodetect mode, or point the tool the right port.

Ubuntu/Mint GNU/Linux

For USB

The live tracking works both with GPSD gpsd / dev / ttyACM3 or without it, by connecting the QGIS live tracking tool directly to the device (for example /dev/ttyACM3).

For Bluetooth

The live tracking works both with GPSD

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gpsd / dev / rfcomm0

.

or without it, by connecting the QGIS live tracking tool directly to the device (for example /dev/rfcomm0).

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16

GRASS GIS Integration

The GRASS plugin provides access to GRASS GIS databases and functionalities (see GRASS-PROJECT in

Literature and Web References ). This includes visualizing GRASS raster and vector layers, digitizing vector layers,

editing vector attributes, creating new vector layers and analysing GRASS 2-D and 3-D data with more than 400

GRASS modules.

In this section, we’ll introduce the plugin functionalities and give some examples of managing and working with

GRASS data. The following main features are provided with the toolbar menu when you start the GRASS plugin, as described in section

sec_starting_grass :

Open mapset

New mapset

Close mapset

Add GRASS vector layer

Add GRASS raster layer

Create new GRASS vector

Edit GRASS vector layer

Open GRASS tools

Display current GRASS region

Edit current GRASS region

16.1 Starting the GRASS plugin

To use GRASS functionalities and/or visualize GRASS vector and raster layers in QGIS, you must select and load the GRASS plugin with the Plugin Manager. Therefore, go to the menu Plugins →

GRASS and click [OK].

Manage Plugins , select

You can now start loading raster and vector layers from an existing GRASS LOCATION (see section

sec_load_grassdata ). Or, you can create a new GRASS LOCATION with QGIS (see section Creating a new GRASS

LOCATION ) and import some raster and vector data (see section

Importing data into a GRASS LOCATION ) for

further analysis with the GRASS Toolbox (see section

The GRASS Toolbox ).

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16.2 Loading GRASS raster and vector layers

With the GRASS plugin, you can load vector or raster layers using the appropriate button on the toolbar menu. As an example, we will use the QGIS Alaska dataset (see section

Sample Data ). It includes a small sample GRASS

LOCATION with three vector layers and one raster elevation map.

1. Create a new folder called grassdata

, download the QGIS ‘Alaska’ dataset qgis_sample_data.zip

from http://download.osgeo.org/qgis/data/ and unzip the file into grassdata

.

2. Start QGIS.

3. If not already done in a previous QGIS session, load the GRASS plugin clicking on Plugins →

Plugins and activate

GRASS

. The GRASS toolbar appears in the QGIS main window.

4. In the GRASS toolbar, click the

Open mapset icon to bring up the MAPSET wizard.

5. For Gisdbase, browse and select or enter the path to the newly created folder grassdata.

6. You should now be able to select the LOCATION alaska and the MAPSET demo

.

7. Click [OK]. Notice that some previously disabled tools in the GRASS toolbar are now enabled.

Manage

8. Click on be visualized.

Add GRASS raster layer

, choose the map name gtopo30 and click [OK]. The elevation layer will

9. Click on

Add GRASS vector layer

, choose the map name alaska and click [OK]. The Alaska boundary vector layer will be overlayed on top of the gtopo30 map. You can now adapt the layer properties as described in chapter

The Vector Properties Dialog

(e.g., change opacity, fill and outline color).

10. Also load the other two vector layers, rivers and airports, and adapt their properties.

As you see, it is very simple to load GRASS raster and vector layers in QGIS. See the following sections for editing GRASS data and creating a new LOCATION. More sample GRASS LOCATIONs are available at the

GRASS website at http://grass.osgeo.org/download/sample-data/ .

Vihje: GRASS Data Loading

If you have problems loading data or QGIS terminates abnormally, check to make sure you have loaded the

GRASS plugin properly as described in section

Starting the GRASS plugin .

16.3 GRASS LOCATION and MAPSET

GRASS data are stored in a directory referred to as GISDBASE. This directory, often called grassdata, must be created before you start working with the GRASS plugin in QGIS. Within this directory, the GRASS GIS data are organized by projects stored in subdirectories called LOCATIONs. Each LOCATION is defined by its coordinate system, map projection and geographical boundaries. Each LOCATION can have several MAPSETs

(subdirectories of the LOCATION) that are used to subdivide the project into different topics or subregions, or as workspaces for individual team members (see Neteler & Mitasova 2008 in

Literature and Web References ). In

order to analyze vector and raster layers with GRASS modules, you must import them into a GRASS LOCATION.

(This is not strictly true – with the GRASS modules r.external and v.external you can create read-only links to external GDAL/OGR-supported datasets without importing them. But because this is not the usual way for beginners to work with GRASS, this functionality will not be described here.)

16.3.1 Creating a new GRASS LOCATION

As an example, here is how the sample GRASS LOCATION alaska, which is projected in Albers Equal Area projection with unit feet was created for the QGIS sample dataset. This sample GRASS LOCATION alaska

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Kuva 16.1: GRASS data in the alaska LOCATION will be used for all examples and exercises in the following GRASS-related sections. It is useful to download and install the dataset on your computer (see

Sample Data

).

1. Start QGIS and make sure the GRASS plugin is loaded.

2. Visualize the alaska.shp shapefile (see section

Loading a Shapefile ) from the QGIS Alaska dataset (see

Sample Data ).

3. In the GRASS toolbar, click on the

New mapset icon to bring up the MAPSET wizard.

4. Select an existing GRASS database (GISDBASE) folder grassdata, or create one for the new

LOCATION using a file manager on your computer. Then click [Next].

5. We can use this wizard to create a new MAPSET within an existing LOCATION (see section

Adding a new MAPSET ) or to create a new LOCATION altogether. Select ure_grass_location_2 ).

Create new location (see

fig-

6. Enter a name for the LOCATION – we used ‘alaska’ – and click [Next].

7. Define the projection by clicking on the radio button Projection to enable the projection list.

8. We are using Albers Equal Area Alaska (feet) projection. Since we happen to know that it is represented by the EPSG ID 2964, we enter it in the search box. (Note: If you want to repeat this process for another

LOCATION and projection and haven’t memorized the EPSG ID, click on the right-hand corner of the status bar (see section

Working with Projections

)).

CRS Status icon in the lower

9. In Filter, insert 2964 to select the projection.

10. Click [Next].

11. To define the default region, we have to enter the LOCATION bounds in the north, south, east, and west directions. Here, we simply click on the button [Set current |qg| extent], to apply the extent of the loaded layer alaska.shp as the GRASS default region extent.

12. Click [Next].

13. We also need to define a MAPSET within our new LOCATION (this is necessary when creating a new

LOCATION ). You can name it whatever you like - we used ‘demo’. GRASS automatically creates a special

MAPSET called PERMANENT, designed to store the core data for the project, its default spatial extent and coordinate system definitions (see Neteler & Mitasova 2008 in

Literature and Web References ).

14. Check out the summary to make sure it’s correct and click [Finish].

15. The new LOCATION, ‘alaska’, and two MAPSETs, ‘demo’ and ‘PERMANENT’, are created. The currently opened working set is ‘demo’, as you defined.

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16. Notice that some of the tools in the GRASS toolbar that were disabled are now enabled.

Kuva 16.2: Creating a new GRASS LOCATION or a new MAPSET in QGIS

If that seemed like a lot of steps, it’s really not all that bad and a very quick way to create a LOCATION. The

LOCATION

‘alaska’ is now ready for data import (see section

Importing data into a GRASS LOCATION

). You

can also use the already-existing vector and raster data in the sample GRASS LOCATION ‘alaska’, included in the QGIS ‘Alaska’ dataset

Sample Data , and move on to section

The GRASS vector data model .

16.3.2 Adding a new MAPSET

A user has write access only to a GRASS MAPSET he or she created. This means that besides access to your own

MAPSET , you can read maps in other users’ MAPSETs (and they can read yours), but you can modify or remove only the maps in your own MAPSET.

All MAPSETs include a WIND file that stores the current boundary coordinate values and the currently selected raster resolution (see Neteler & Mitasova 2008 in

Literature and Web References , and section

The GRASS region tool ).

1. Start QGIS and make sure the GRASS plugin is loaded.

2. In the GRASS toolbar, click on the

3. Select the GRASS database (GISDBASE) folder grassdata with the LOCATION ‘alaska’, where we want to add a further MAPSET called ‘test’.

4. Click [Next].

New mapset icon to bring up the MAPSET wizard.

5. We can use this wizard to create a new MAPSET within an existing LOCATION or to create a new

LOCATION altogether. Click on the radio button Select location (see

figure_grass_location_2 ) and click

[Next].

6. Enter the name text for the new MAPSET. Below in the wizard, you see a list of existing MAPSETs and corresponding owners.

7. Click [Next], check out the summary to make sure it’s all correct and click [Finish].

16.4 Importing data into a GRASS LOCATION

This section gives an example of how to import raster and vector data into the ‘alaska’ GRASS LOCATION provided by the QGIS ‘Alaska’ dataset. Therefore, we use the landcover raster map landcover.img and the vector GML file lakes.gml from the QGIS ‘Alaska’ dataset (see

Sample Data ).

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1. Start QGIS and make sure the GRASS plugin is loaded.

2. In the GRASS toolbar, click the

Open MAPSET icon to bring up the MAPSET wizard.

3. Select as GRASS database the folder grassdata in the QGIS Alaska dataset, as LOCATION ‘alaska’, as

MAPSET

‘demo’ and click [OK].

4. Now click the pears.

Open GRASS tools icon. The GRASS Toolbox (see section

The GRASS Toolbox ) dialog ap-

5. To import the raster map landcover.img, click the module r.in.gdal in the Modules Tree tab. This

GRASS module allows you to import GDAL-supported raster files into a GRASS LOCATION. The module dialog for r.in.gdal appears.

6. Browse to the folder raster in the QGIS ‘Alaska’ dataset and select the file landcover.img.

7. As raster output name, define landcover_grass and click [Run]. In the Output tab, you see the currently running GRASS command r.in.gdal -o input=/path/to/landcover.img

output=landcover_grass

.

8. When it says Succesfully finished, click [View output]. The landcover_grass raster layer is now imported into GRASS and will be visualized in the QGIS canvas.

9. To import the vector GML file lakes.gml, click the module v.in.ogr in the Modules Tree tab. This

GRASS module allows you to import OGR-supported vector files into a GRASS LOCATION. The module dialog for v.in.ogr appears.

10. Browse to the folder gml in the QGIS ‘Alaska’ dataset and select the file lakes.gml as OGR file.

11. As vector output name, define lakes_grass and click [Run]. You don’t have to care about the other options in this example. In the Output tab you see the currently running GRASS command v.in.ogr -o dsn=/path/to/lakes.gml output=lakes\_grass

.

12. When it says Succesfully finished, click [View output]. The lakes_grass vector layer is now imported into GRASS and will be visualized in the QGIS canvas.

16.5 The GRASS vector data model

It is important to understand the GRASS vector data model prior to digitizing.

In general, GRASS uses a topological vector model.

This means that areas are not represented as closed polygons, but by one or more boundaries. A boundary between two adjacent areas is digitized only once, and it is shared by both areas. Boundaries must be connected and closed without gaps. An area is identified (and labeled) by the centroid of the area.

Besides boundaries and centroids, a vector map can also contain points and lines. All these geometry elements can be mixed in one vector and will be represented in different so-called ‘layers’ inside one GRASS vector map. So in GRASS, a layer is not a vector or raster map but a level inside a vector layer. This is important to distinguish carefully. (Although it is possible to mix geometry elements, it is unusual and, even in GRASS, only used in special cases such as vector network analysis. Normally, you should prefer to store different geometry elements in different layers.)

It is possible to store several ‘layers’ in one vector dataset. For example, fields, forests and lakes can be stored in one vector. An adjacent forest and lake can share the same boundary, but they have separate attribute tables. It is also possible to attach attributes to boundaries. An example might be the case where the boundary between a lake and a forest is a road, so it can have a different attribute table.

The ‘layer’ of the feature is defined by the ‘layer’ inside GRASS. ‘Layer’ is the number which defines if there is more than one layer inside the dataset (e.g., if the geometry is forest or lake). For now, it can be only a number. In the future, GRASS will also support names as fields in the user interface.

Attributes can be stored inside the GRASS LOCATION as dBase or SQLite3 or in external database tables, for example, PostgreSQL, MySQL, Oracle, etc.

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Attributes in database tables are linked to geometry elements using a ‘category’ value.

‘Category’ (key, ID) is an integer attached to geometry primitives, and it is used as the link to one key column in the database table.

Vihje: Learning the GRASS Vector Model

The best way to learn the GRASS vector model and its capabilities is to download one of the many GRASS tutorials where the vector model is described more deeply. See http://grass.osgeo.org/documentation/manuals/ for more information, books and tutorials in several languages.

16.6 Creating a new GRASS vector layer

To create a new GRASS vector layer with the GRASS plugin, click the

Create new GRASS vector toolbar icon. Enter a name in the text box, and you can start digitizing point, line or polygon geometries following the procedure described in section

Digitizing and editing a GRASS vector layer

.

In GRASS, it is possible to organize all sorts of geometry types (point, line and area) in one layer, because GRASS uses a topological vector model, so you don’t need to select the geometry type when creating a new GRASS vector.

This is different from shapefile creation with QGIS, because shapefiles use the Simple Feature vector model (see section

Creating new Vector layers ).

Vihje: Creating an attribute table for a new GRASS vector layer

If you want to assign attributes to your digitized geometry features, make sure to create an attribute table with columns before you start digitizing (see

figure_grass_digitizing_5 ).

16.7 Digitizing and editing a GRASS vector layer

The digitizing tools for GRASS vector layers are accessed using the

Edit GRASS vector layer icon on the toolbar.

Make sure you have loaded a GRASS vector and it is the selected layer in the legend before clicking on the edit tool. Figure

figure_grass_digitizing_2

shows the GRASS edit dialog that is displayed when you click on the edit tool. The tools and settings are discussed in the following sections.

Vihje: Digitizing polygons in GRASS

If you want to create a polygon in GRASS, you first digitize the boundary of the polygon, setting the mode to ‘No category’. Then you add a centroid (label point) into the closed boundary, setting the mode to ‘Next not used’.

The reason for this is that a topological vector model links the attribute information of a polygon always to the centroid and not to the boundary.

Toolbar

In

figure_grass_digitizing_1 ,

you see the GRASS digitizing toolbar icons provided by the GRASS plugin.

Table

table_grass_digitizing_1

explains the available functionalities.

Kuva 16.3: GRASS Digitizing Toolbar

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Icon Tool

New Point

New Line

New

Boundary

Purpose

Digitize new point

Digitize new line

Digitize new boundary (finish by selecting new tool)

New

Centroid

Digitize new centroid (label existing area)

Move vertex Move one vertex of existing line or boundary and identify new position

Add vertex Add a new vertex to existing line

Delete vertex Delete vertex from existing line (confirm selected vertex by another click)

Move selected boundary, line, point or centroid and click on new position Move element

Split line

Delete element

Edit attributes

Split an existing line into two parts

Delete existing boundary, line, point or centroid (confirm selected element by another click)

Edit attributes of selected element (note that one element can represent more features, see above)

Close Close session and save current status (rebuilds topology afterwards)

Table GRASS Digitizing 1: GRASS Digitizing Tools

Category Tab

The Category tab allows you to define the way in which the category values will be assigned to a new geometry element.

Kuva 16.4: GRASS Digitizing Category Tab

• Mode: The category value that will be applied to new geometry elements.

– Next not used - Apply next not yet used category value to geometry element.

– Manual entry - Manually define the category value for the geometry element in the ‘Category’ entry field.

– No category - Do not apply a category value to the geometry element. This is used, for instance, for area boundaries, because the category values are connected via the centroid.

• Category - The number (ID) that is attached to each digitized geometry element. It is used to connect each geometry element with its attributes.

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• Field (layer) - Each geometry element can be connected with several attribute tables using different GRASS geometry layers. The default layer number is 1.

Vihje: Creating an additional GRASS ‘layer’ with |qg|

If you would like to add more layers to your dataset, just add a new number in the ‘Field (layer)’ entry box and press return. In the Table tab, you can create your new table connected to your new layer.

Settings Tab

The Settings tab allows you to set the snapping in screen pixels. The threshold defines at what distance new points or line ends are snapped to existing nodes. This helps to prevent gaps or dangles between boundaries. The default is set to 10 pixels.

Kuva 16.5: GRASS Digitizing Settings Tab

Symbology Tab

The Symbology tab allows you to view and set symbology and color settings for various geometry types and their topological status (e.g., closed / opened boundary).

Kuva 16.6: GRASS Digitizing Symbology Tab

Table Tab

The Table tab provides information about the database table for a given ‘layer’. Here, you can add new columns to an existing attribute table, or create a new database table for a new GRASS vector layer (see section

Creating a new GRASS vector layer ).

Vihje: GRASS Edit Permissions

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Kuva 16.7: GRASS Digitizing Table Tab

You must be the owner of the GRASS MAPSET you want to edit. It is impossible to edit data layers in a MAPSET that is not yours, even if you have write permission.

16.8 The GRASS region tool

The region definition (setting a spatial working window) in GRASS is important for working with raster layers.

Vector analysis is by default not limited to any defined region definitions. But all newly created rasters will have the spatial extension and resolution of the currently defined GRASS region, regardless of their original extension and resolution. The current GRASS region is stored in the $LOCATION/$MAPSET/WIND file, and it defines north, south, east and west bounds, number of columns and rows, horizontal and vertical spatial resolution.

It is possible to switch on and off the visualization of the GRASS region in the QGIS canvas using the

Display current GRASS region button.

With the

Edit current GRASS region icon, you can open a dialog to change the current region and the symbology of the GRASS region rectangle in the QGIS canvas. Type in the new region bounds and resolution, and click [OK].

The dialog also allows you to select a new region interactively with your mouse on the QGIS canvas. Therefore, click with the left mouse button in the QGIS canvas, open a rectangle, close it using the left mouse button again and click [OK].

The GRASS module g.region provides a lot more parameters to define an appropriate region extent and resolution for your raster analysis. You can use these parameters with the GRASS Toolbox, described in section

The

GRASS Toolbox

.

16.9 The GRASS Toolbox

The

Open GRASS Tools box provides GRASS module functionalities to work with data inside a selected GRASS

LOCATION and MAPSET. To use the GRASS Toolbox you need to open a LOCATION and MAPSET that you have write permission for (usually granted, if you created the MAPSET). This is necessary, because new raster or vector layers created during analysis need to be written to the currently selected LOCATION and MAPSET.

16.9.1 Working with GRASS modules

The GRASS shell inside the GRASS Toolbox provides access to almost all (more than 300) GRASS modules in a command line interface. To offer a more user-friendly working environment, about 200 of the available GRASS modules and functionalities are also provided by graphical dialogs within the GRASS plugin Toolbox.

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Kuva 16.8: GRASS Toolbox and Module Tree

A complete list of GRASS modules available in the graphical Toolbox in QGIS version 2.6 is available in the

GRASS wiki at http://grass.osgeo.org/wiki/GRASS-QGIS_relevant_module_list .

It is also possible to customize the GRASS Toolbox content. This procedure is described in section

Customizing the GRASS Toolbox

.

As shown in

figure_grass_toolbox_1 , you can look for the appropriate GRASS module using the thematically

grouped Modules Tree or the searchable Modules List tab.

By clicking on a graphical module icon, a new tab will be added to the Toolbox dialog, providing three new sub-tabs: Options, Output and Manual.

Options

The Options tab provides a simplified module dialog where you can usually select a raster or vector layer visualized in the QGIS canvas and enter further module-specific parameters to run the module.

The provided module parameters are often not complete to keep the dialog clear. If you want to use further module parameters and flags, you need to start the GRASS shell and run the module in the command line.

A new feature since QGIS 1.8 is the support for a Show Advanced Options button below the simplified module dialog in the Options tab. At the moment, it is only added to the module v.in.ascii as an example of use, but it will probably be part of more or all modules in the GRASS Toolbox in future versions of QGIS. This allows you to use the complete GRASS module options without the need to switch to the GRASS shell.

Output

The Output tab provides information about the output status of the module. When you click the [Run] button, the module switches to the Output tab and you see information about the analysis process. If all works well, you will finally see a Successfully finished message.

Manual

The Manual tab shows the HTML help page of the GRASS module. You can use it to check further module parameters and flags or to get a deeper knowledge about the purpose of the module. At the end of each module manual page, you see further links to the Main Help index, the Thematic index and the Full index.

These links provide the same information as the module g.manual.

Vihje: Display results immediately

If you want to display your calculation results immediately in your map canvas, you can use the ‘View Output’ button at the bottom of the module tab.

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16.9.2 GRASS module examples

The following examples will demonstrate the power of some of the GRASS modules.

Creating contour lines

The first example creates a vector contour map from an elevation raster (DEM). Here, it is assumed that you have the Alaska LOCATION set up as explained in section

Importing data into a GRASS LOCATION .

• First, open the location by clicking the

Open mapset button and choosing the Alaska location.

• Now load the gtopo30 elevation raster by clicking raster from the demo location.

Add GRASS raster layer and selecting the gtopo30

• Now open the Toolbox with the

Open GRASS tools button.

• In the list of tool categories, double-click Raster → Surface Management → Generate vector contour lines.

• Now a single click on the tool r.contour will open the tool dialog as explained above (see

Working with

GRASS modules ). The gtopo30 raster should appear as the Name of input raster.

• Type into the Increment between Contour levels intervals of 100 meters.) the value 100. (This will create contour lines at

• Type into the Name for output vector map the name ctour_100.

• Click [Run] to start the process. Wait for several moments until the message Successfully finished appears in the output window. Then click [View Output] and [Close].

Since this is a large region, it will take a while to display. After it finishes rendering, you can open the layer properties window to change the line color so that the contours appear clearly over the elevation raster, as in

The

Vector Properties Dialog .

Next, zoom in to a small, mountainous area in the center of Alaska. Zooming in close, you will notice that the contours have sharp corners. GRASS offers the v.generalize tool to slightly alter vector maps while keeping their

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overall shape. The tool uses several different algorithms with different purposes. Some of the algorithms (i.e.,

Douglas Peuker and Vertex Reduction) simplify the line by removing some of the vertices. The resulting vector will load faster. This process is useful when you have a highly detailed vector, but you are creating a very smallscale map, so the detail is unnecessary.

Vihje: The simplify tool

Note that the QGIS fTools plugin has a Simplify geometries → tool that works just like the GRASS v.generalize

Douglas-Peuker algorithm.

However, the purpose of this example is different. The contour lines created by r.contour have sharp angles that should be smoothed. Among the v.generalize algorithms, there is Chaiken’s, which does just that (also Hermite splines). Be aware that these algorithms can add additional vertices to the vector, causing it to load even more slowly.

• Open the GRASS Toolbox and double-click the categories Vector → Develop map → Generalization, then click on the v.generalize module to open its options window.

• Check that the ‘ctour_100’ vector appears as the Name of input vector.

• From the list of algorithms, choose Chaiken’s. Leave all other options at their default, and scroll down to the last row to enter in the field Name for output vector map ‘ctour_100_smooth’, and click [Run].

• The process takes several moments. Once Successfully finished appears in the output windows, click [View output] and then [Close].

• You may change the color of the vector to display it clearly on the raster background and to contrast with the original contour lines. You will notice that the new contour lines have smoother corners than the original while staying faithful to the original overall shape.

Kuva 16.12: GRASS module v.generalize to smooth a vector map

Vihje: Other uses for r.contour

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The procedure described above can be used in other equivalent situations. If you have a raster map of precipitation data, for example, then the same method will be used to create a vector map of isohyetal (constant rainfall) lines.

Creating a Hillshade 3-D effect

Several methods are used to display elevation layers and give a 3-D effect to maps. The use of contour lines, as shown above, is one popular method often chosen to produce topographic maps. Another way to display a 3-D effect is by hillshading. The hillshade effect is created from a DEM (elevation) raster by first calculating the slope and aspect of each cell, then simulating the sun’s position in the sky and giving a reflectance value to each cell.

Thus, you get sun-facing slopes lighted; the slopes facing away from the sun (in shadow) are darkened.

• Begin this example by loading the gtopo30 elevation raster. Start the GRASS Toolbox, and under the

Raster category, double-click to open Spatial analysis → Terrain analysis.

• Then click r.shaded.relief to open the module.

• Change the azimuth angle 270 to 315.

• Enter gtopo30_shade for the new hillshade raster, and click [Run].

• When the process completes, add the hillshade raster to the map. You should see it displayed in grayscale.

• To view both the hillshading and the colors of the gtopo30 together, move the hillshade map below the gtopo30 map in the table of contents, then open the Properties window of gtopo30, switch to the

Transparency tab and set its transparency level to about 25%.

You should now have the gtopo30 elevation with its colormap and transparency setting displayed above the grayscale hillshade map. In order to see the visual effects of the hillshading, turn off the gtopo30_shade map, then turn it back on.

Using the GRASS shell

The GRASS plugin in QGIS is designed for users who are new to GRASS and not familiar with all the modules and options. As such, some modules in the Toolbox do not show all the options available, and some modules do not appear at all. The GRASS shell (or console) gives the user access to those additional GRASS modules that do not appear in the Toolbox tree, and also to some additional options to the modules that are in the Toolbox with the simplest default parameters. This example demonstrates the use of an additional option in the r.shaded.relief

module that was shown above.

The module r.shaded.relief can take a parameter zmult, which multiplies the elevation values relative to the X-Y coordinate units so that the hillshade effect is even more pronounced.

• Load the gtopo30 elevation raster as above, then start the GRASS Toolbox and click on the GRASS shell. In the shell window, type the command r.shaded.relief map=gtopo30 shade=gtopo30_shade2 azimuth=315 zmult=3 and press [Enter].

• After the process finishes, shift to the Browse tab and double-click on the new gtopo30_shade2 raster to display it in QGIS.

• As explained above, move the shaded relief raster below the gtopo30 raster in the table of contents, then check the transparency of the colored gtopo30 layer. You should see that the 3-D effect stands out more strongly compared with the first shaded relief map.

Raster statistics in a vector map

The next example shows how a GRASS module can aggregate raster data and add columns of statistics for each polygon in a vector map.

• Again using the Alaska data, refer to

Importing data into a GRASS LOCATION

to import the trees shapefile from the shapefiles directory into GRASS.

• Now an intermediate step is required: centroids must be added to the imported trees map to make it a complete GRASS area vector (including both boundaries and centroids).

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Kuva 16.14: Displaying shaded relief created with the GRASS module r.shaded.relief

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• From the Toolbox, choose Vector → Manage features, and open the module v.centroids.

• Enter as the output vector map ‘forest_areas’ and run the module.

• Now load the forest_areas vector and display the types of forests - deciduous, evergreen, mixed - in different colors: In the layer Properties window, Symbology tab, choose from Legend type ‘Unique value’ and set the Classification field to ‘VEGDESC’. (Refer to the explanation of the symbology tab in

Style Menu

of the vector section.)

• Next, reopen the GRASS Toolbox and open Vector → Vector update by other maps.

• Click on the v.rast.stats module. Enter gtopo30 and forest_areas.

• Only one additional parameter is needed: Enter column prefix elev, and click [Run]. This is a computationally heavy operation, which will run for a long time (probably up to two hours).

• Finally, open the forest_areas attribute table, and verify that several new columns have been added, including elev_min, elev_max, elev_mean, etc., for each forest polygon.

16.9.3 Working with the GRASS LOCATION browser

Another useful feature inside the GRASS Toolbox is the GRASS LOCATION browser. In

figure_grass_module_7 ,

you can see the current working LOCATION with its MAPSETs.

In the left browser windows, you can browse through all MAPSETs inside the current LOCATION. The right browser window shows some meta-information for selected raster or vector layers (e.g., resolution, bounding box, data source, connected attribute table for vector data, and a command history).

Kuva 16.15: GRASS LOCATION browser

The toolbar inside the Browser tab offers the following tools to manage the selected LOCATION:

• Add selected map to canvas

Copy selected map

Rename selected map

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Delete selected map

Set current region to selected map

• Refresh browser window

The Rename selected map and Delete selected map only work with maps inside your currently selected

MAPSET

. All other tools also work with raster and vector layers in another MAPSET.

16.9.4 Customizing the GRASS Toolbox

Nearly all GRASS modules can be added to the GRASS Toolbox. An XML interface is provided to parse the pretty simple XML files that configure the modules’ appearance and parameters inside the Toolbox.

A sample XML file for generating the module v.buffer (v.buffer.qgm) looks like this:

<?xml version="1.0" encoding="UTF-8"?>

<!DOCTYPE qgisgrassmodule SYSTEM "http://mrcc.com/qgisgrassmodule.dtd">

<qgisgrassmodule label="Vector buffer" module="v.buffer">

<option key="input" typeoption="type" layeroption="layer" />

<option key="buffer"/>

<option key="output" />

</qgisgrassmodule>

.

The parser reads this definition and creates a new tab inside the Toolbox when you select the module. A more detailed description for adding new modules, changing a module’s group, etc., can be found on the QGIS wiki at http://hub.qgis.org/projects/quantum-gis/wiki/Adding_New_Tools_to_the_GRASS_Toolbox .

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QGIS processing framework

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17.1 Introduction

This chapter introduces the QGIS processing framework, a geoprocessing environment that can be used to call native and third-party algorithms from QGIS, making your spatial analysis tasks more productive and easy to accomplish.

In the following sections, we will review how to use the graphical elements of this framework and make the most out of each one of them.

There are four basic elements in the framework GUI, which are used to run algorithms for different purposes.

Choosing one tool or another will depend on the kind of analysis that is to be performed and the particular characteristics of each user and project. All of them (except for the batch processing interface, which is called from the toolbox, as we will see) can be accessed from the Processing menu item. (You will see more than four entries. The remaining ones are not used to execute algorithms and will be explained later in this chapter.)

• The toolbox. The main element of the GUI, it is used to execute a single algorithm or run a batch process based on that algorithm.

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• The graphical modeler. Several algorithms can be combined graphically using the modeler to define a workflow, creating a single process that involves several subprocesses.

Kuva 17.2: Processing Modeler

• The history manager. All actions performed using any of the aforementioned elements are stored in a history file and can be later easily reproduced using the history manager.

• The batch processing interface. This interface allows you to execute batch processes and automate the execution of a single algorithm on multiple datasets.

.

In the following sections, we will review each one of these elements in detail.

17.2 The toolbox

The Toolbox is the main element of the processing GUI, and the one that you are more likely to use in your daily work. It shows the list of all available algorithms grouped in different blocks, and it is the access point to run them, whether as a single process or as a batch process involving several executions of the same algorithm on different sets of inputs.

The toolbox contains all the available algorithms, divided into predefined groups. All these groups are found under a single tree entry named Geoalgorithms.

Additionally, two more entries are found, namely Models and Scripts. These include user-created algorithms, and they allow you to define your own workflows and processing tasks. We will devote a full section to them a bit later.

In the upper part of the toolbox, you will find a text box. To reduce the number of algorithms shown in the toolbox and make it easier to find the one you need, you can enter any word or phrase on the text box. Notice that, as you type, the number of algorithms in the toolbox is reduced to just those that contain the text you have entered in their names.

In the lower part, you will find a box that allows you to switch between the simplified algorithm list (the one explained above) and the advanced list. If you change to the advanced mode, the toolbox will look like this:

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Kuva 17.3: Processing History

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Kuva 17.4: Batch Processing interface

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In the advanced view, each group represents a so-called ‘algorithm provider’, which is a set of algorithms coming from the same source, for instance, from a third-party application with geoprocessing capabilities. Some of these groups represent algorithms from third-party applications like SAGA, GRASS or R, while others contain algorithms directly coded as part of the processing plugin, not relying on any additional software.

This view is recommended to those users who have a certain knowledge of the applications that are backing the algorithms, since they will be shown with their original names and groups.

Also, some additional algorithms are available only in the advanced view, such as LiDAR tools and scripts based on the R statistical computing software, among others. Independent QGIS plugins that add new algorithms to the toolbox will only be shown in the advanced view.

In particular, the simplified view contains algorithms from the following providers:

• GRASS

• SAGA

• OTB

• Native QGIS algorithms

In the case of running QGIS under Windows, these algorithms are fully-functional in a fresh installation of QGIS, and they can be run without requiring any additional installation. Also, running them requires no prior knowledge of the external applications they use, making them more accesible for first-time users.

If you want to use an algorithm not provided by any of the above providers, switch to the advanced mode by selecting the corresponding option at the bottom of the toolbox.

To execute an algorithm, just double-click on its name in the toolbox.

17.2.1 The algorithm dialog

Once you double-click on the name of the algorithm that you want to execute, a dialog similar to that in the figure below is shown (in this case, the dialog corresponds to the SAGA ‘Convergence index’ algorithm).

Kuva 17.7: Parameters Dialog

This dialog is used to set the input values that the algorithm needs to be executed. It shows a table where input values and configuration parameters are to be set. It of course has a different content, depending on the require-

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ments of the algorithm to be executed, and is created automatically based on those requirements. On the left side, the name of the parameter is shown. On the right side, the value of the parameter can be set.

Although the number and type of parameters depend on the characteristics of the algorithm, the structure is similar for all of them. The parameters found in the table can be of one of the following types.

• A raster layer, to select from a list of all such layers available (currently opened) in QGIS. The selector contains as well a button on its right-hand side, to let you select filenames that represent layers currently not loaded in QGIS.

• A vector layer, to select from a list of all vector layers available in QGIS. Layers not loaded in QGIS can be selected as well, as in the case of raster layers, but only if the algorithm does not require a table field selected from the attributes table of the layer. In that case, only opened layers can be selected, since they need to be open so as to retrieve the list of field names available.

You will see a button by each vector layer selector, as shown in the figure below.

Kuva 17.8: Vector iterator button

If the algorithm contains several of them, you will be able to toggle just one of them. If the button corresponding to a vector input is toggled, the algorithm will be executed iteratively on each one of its features, instead of just once for the whole layer, producing as many outputs as times the algorithm is executed. This allows for automating the process when all features in a layer have to be processed separately.

• A table, to select from a list of all available in QGIS. Non-spatial tables are loaded into QGIS like vector layers, and in fact they are treated as such by the program. Currently, the list of available tables that you will see when executing an algorithm that needs one of them is restricted to tables coming from files in dBase

(.dbf) or Comma-Separated Values (.csv) formats.

• An option, to choose from a selection list of possible options.

• A numerical value, to be introduced in a text box. You will find a button by its side. Clicking on it, you will see a dialog that allows you to enter a mathematical expression, so you can use it as a handy calculator.

Some useful variables related to data loaded into QGIS can be added to your expression, so you can select a value derived from any of these variables, such as the cell size of a layer or the northernmost coordinate of another one.

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• A range, with min and max values to be introduced in two text boxes.

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• A text string, to be introduced in a text box.

• A field, to choose from the attributes table of a vector layer or a single table selected in another parameter.

• A coordinate reference system. You can type the EPSG code directly in the text box, or select it from the

CRS selection dialog that appears when you click on the button on the right-hand side.

• An extent, to be entered by four numbers representing its xmin, xmax, ymin, ymax limits. Clicking on the button on the right-hand side of the value selector, a pop-up menu will appear, giving you two options: to select the value from a layer or the current canvas extent, or to define it by dragging directly onto the map canvas.

Kuva 17.10: Extent selector

If you select the first option, you will see a window like the next one.

Kuva 17.11: Extent List

If you select the second one, the parameters window will hide itself, so you can click and drag onto the canvas. Once you have defined the selected rectangle, the dialog will reappear, containing the values in the extent text box.

Kuva 17.12: Extent Drag

• A list of elements (whether raster layers, vector layers or tables), to select from the list of such layers available in QGIS. To make the selection, click on the small button on the left side of the corresponding row to see a dialog like the following one.

• A small table to be edited by the user. These are used to define parameters like lookup tables or convolution kernels, among others.

Click on the button on the right side to see the table and edit its values.

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Depending on the algorithm, the number of rows can be modified or not by using the buttons on the right side of the window.

You will find a [Help] tab in the the parameters dialog. If a help file is available, it will be shown, giving you more information about the algorithm and detailed descriptions of what each parameter does. Unfortunately, most algorithms lack good documentation, but if you feel like contributing to the project, this would be a good place to start.

A note on projections

Algorithms run from the processing framework — this is also true of most of the external applications whose algorithms are exposed through it. Do not perform any reprojection on input layers and assume that all of them are already in a common coordinate system and ready to be analized. Whenever you use more than one layer as input to an algorithm, whether vector or raster, it is up to you to make sure that they are all in the same coordinate system.

Note that, due to QGIS‘s on-the-fly reprojecting capabilities, although two layers might seem to overlap and match, that might not be true if their original coordinates are used without reprojecting them onto a common coordinate system. That reprojection should be done manually, and then the resulting files should be used as input to the algorithm. Also, note that the reprojection process can be performed with the algorithms that are available in the processing framework itself.

By default, the parameters dialog will show a description of the CRS of each layer along with its name, making it easy to select layers that share the same CRS to be used as input layers. If you do not want to see this additional information, you can disable this functionality in the processing configuration dialog, unchecking the Show CRS option.

If you try to execute an algorithm using as input two or more layers with unmatching CRSs, a warning dialog will be shown.

You still can execute the algorithm, but be aware that in most cases that will produce wrong results, such as empty layers due to input layers not overlapping.

17.2.2 Data objects generated by algorithms

Data objects generated by an algorithm can be of any of the following types:

• A raster layer

• A vector layer

• A table

• An HTML file (used for text and graphical outputs)

These are all saved to disk, and the parameters table will contain a text box corresponding to each one of these outputs, where you can type the output channel to use for saving it. An output channel contains the information needed to save the resulting object somewhere. In the most usual case, you will save it to a file, but the architecture allows for any other way of storing it. For instance, a vector layer can be stored in a database or even uploaded to a remote server using a WFS-T service. Although solutions like these are not yet implemented, the processing framework is prepared to handle them, and we expect to add new kinds of output channels in a near feature.

To select an output channel, just click on the button on the right side of the text box. That will open a save file dialog, where you can select the desired file path. Supported file extensions are shown in the file format selector of the dialog, depending on the kind of output and the algorithm.

The format of the output is defined by the filename extension. The supported formats depend on what is supported by the algorithm itself. To select a format, just select the corresponding file extension (or add it, if you are directly typing the file path instead). If the extension of the file path you entered does not match any of the supported formats, a default extension (usually .dbf‘ for tables, .tif for raster layers and .shp for vector layers) will be appended to the file path, and the file format corresponding to that extension will be used to save the layer or table.

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If you do not enter any filename, the result will be saved as a temporary file in the corresponding default file format, and it will be deleted once you exit QGIS (take care with that, in case you save your project and it contains temporary layers).

You can set a default folder for output data objects. Go to the configuration dialog (you can open it from the

Processing menu), and in the General group, you will find a parameter named Output folder. This output folder is used as the default path in case you type just a filename with no path (i.e., myfile.shp) when executing an algorithm.

When running an algorithm that uses a vector layer in iterative mode, the entered file path is used as the base path for all generated files, which are named using the base name and appending a number representing the index of the iteration. The file extension (and format) is used for all such generated files.

Apart from raster layers and tables, algorithms also generate graphics and text as HTML files. These results are shown at the end of the algorithm execution in a new dialog. This dialog will keep the results produced by any algorithm during the current session, and can be shown at any time by selecting Processing → Results viewer from the QGIS main menu.

Some external applications might have files (with no particular extension restrictions) as output, but they do not belong to any of the categories above. Those output files will not be processed by QGIS (opened or included into the current QGIS project), since most of the time they correspond to file formats or elements not supported by

QGIS. This is, for instance, the case with LAS files used for LiDAR data. The files get created, but you won’t see anything new in your QGIS working session.

For all the other types of output, you will find a checkbox that you can use to tell the algorithm whether to load the file once it is generated by the algorithm or not. By default, all files are opened.

Optional outputs are not supported. That is, all outputs are created. However, you can uncheck the corresponding checkbox if you are not interested in a given output, which essentially makes it behave like an optional output (in other words, the layer is created anyway, but if you leave the text box empty, it will be saved to a temporary file and deleted once you exit QGIS).

17.2.3 Configuring the processing framework

As has been mentioned, the configuration menu gives access to a new dialog where you can configure how algorithms work. Configuration parameters are structured in separate blocks that you can select on the left-hand side of the dialog.

Along with the aforementioned Output folder entry, the General block contains parameters for setting the default rendering style for output layers (that is, layers generated by using algorithms from any of the framework GUI components). Just create the style you want using QGIS, save it to a file, and then enter the path to that file in the settings so the algorithms can use it. Whenever a layer is loaded by SEXTANTE and added to the QGIS canvas, it will be rendered with that style.

Rendering styles can be configured individually for each algorithm and each one of its outputs. Just right-click on the name of the algorithm in the toolbox and select Edit rendering styles. You will see a dialog like the one shown next.

Select the style file (.qml) that you want for each output and press [OK].

Other configuration parameters in the General group are listed below:

• Use filename as layer name. The name of each resulting layer created by an algorithm is defined by the algorithm itself. In some cases, a fixed name might be used, meaning that the same output name will be used, no matter which input layer is used. In other cases, the name might depend on the name of the input layer or some of the parameters used to run the algorithm. If this checkbox is checked, the name will be taken from the output filename instead. Notice that, if the output is saved to a temporary file, the filename of this temporary file is usually a long and meaningless one intended to avoid collision with other already existing filenames.

• Use only selected features. If this option is selected, whenever a vector layer is used as input for an algorithm, only its selected features will be used. If the layer has no selected features, all features will be used.

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• Pre-execution script file and Post-execution script file. These parameters refer to scripts written using the processing scripting functionality, and are explained in the section covering scripting and the console.

Apart from the General block in the settings dialog, you will also find a block for algorithm providers. Each entry in this block contains an Activate item that you can use to make algorithms appear or not in the toolbox. Also, some algorithm providers have their own configuration items, which we will explain later when covering particular algorithm providers.

17.3 The graphical modeler

The graphical modeler allows you to create complex models using a simple and easy-to-use interface. When working with a GIS, most analysis operations are not isolated, but rather part of a chain of operations instead.

Using the graphical modeler, that chain of processes can be wrapped into a single process, so it is as easy and convenient to execute as a single process later on a different set of inputs. No matter how many steps and different algorithms it involves, a model is executed as a single algorithm, thus saving time and effort, especially for larger models.

The modeler can be opened from the processing menu.

The modeler has a working canvas where the structure of the model and the workflow it represents are shown. On the left part of the window, a panel with two tabs can be used to add new elements to the model.

Creating a model involves two steps:

1. Definition of necessary inputs. These inputs will be added to the parameters window, so the user can set their values when executing the model. The model itself is an algorithm, so the parameters window is generated automatically as it happens with all the algorithms available in the processing framework.

2. Definition of the workflow. Using the input data of the model, the workflow is defined by adding algorithms and selecting how they use those inputs or the outputs generated by other algorithms already in the model.

17.3.1 Definition of inputs

The first step to create a model is to define the inputs it needs. The following elements are found in the Inputs tab on the left side of the modeler window:

• Raster layer

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• Vector layer

• String

• Table field

• Table

• Extent

• Number

• Boolean

• File

Double-clicking on any of these elements, a dialog is shown to define its characteristics. Depending on the parameter itself, the dialog may contain just one basic element (the description, which is what the user will see when executing the model) or more of them. For instance, when adding a numerical value, as can be seen in the next figure, apart from the description of the parameter, you have to set a default value and a range of valid values.

For each added input, a new element is added to the modeler canvas.

You can also add inputs by dragging the input type from the list and dropping it in the modeler canvas, in the position where you want to place it.

17.3.2 Definition of the workflow

Once the inputs have been defined, it is time to define the algorithms to apply on them. Algorithms can be found in the Algorithms tab, grouped much in the same way as they are in the toolbox.

The appearance of the toolbox has two modes here as well: simplified and advanced. However, there is no element to switch between views in the modeler, so you have to do it in the toolbox. The mode that is selected in the toolbox is the one that will be used for the list of algorithms in the modeler.

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To add an algorithm to a model, double-click on its name or drag and drop it, just like it was done when adding inputs. An execution dialog will appear, with a content similar to the one found in the execution panel that is shown when executing the algorithm from the toolbox. The one shown next corresponds to the SAGA ‘Convergence index’ algorithm, the same example we saw in the section dedicated to the toolbox.

Kuva 17.20: Model Parameters

As you can see, some differences exist. Instead of the file output box that was used to set the file path for output layers and tables, a simple text box is used here. If the layer generated by the algorithm is just a temporary result that will be used as the input of another algorithm and should not be kept as a final result, just do not edit that text box. Typing anything in it means that the result is final and the text that you supply will be the description for the output, which will be the output the user will see when executing the model.

Selecting the value of each parameter is also a bit different, since there are important differences between the context of the modeler and that of the toolbox. Let’s see how to introduce the values for each type of parameter.

• Layers (raster and vector) and tables. These are selected from a list, but in this case, the possible values are not the layers or tables currently loaded in QGIS, but the list of model inputs of the corresponding type, or other layers or tables generated by algorithms already added to the model.

• Numerical values. Literal values can be introduced directly in the text box. But this text box is also a list that can be used to select any of the numerical value inputs of the model. In this case, the parameter will take the value introduced by the user when executing the model.

• String. As in the case of numerical values, literal strings can be typed, or an input string can be selected.

• Table field. The fields of the parent table or layer cannot be known at design time, since they depend on the selection of the user each time the model is executed. To set the value for this parameter, type the name of a field directly in the text box, or use the list to select a table field input already added to the model. The validity of the selected field will be checked at run time.

In all cases, you will find an additional parameter named Parent algorithms that is not available when calling the algorithm from the toolbox. This parameter allows you to define the order in which algorithms are executed by explicitly defining one algorithm as a parent of the current one, which will force the parent algorithm to be executed before the current one.

When you use the output of a previous algorithm as the input of your algorithm, that implicitly sets the previous algorithm as parent of the current one (and places the corresponding arrow in the modeler canvas). However, in some cases an algorithm might depend on another one even if it does not use any output object from it (for

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instance, an algorithm that executes an SQL sentence on a PostGIS database and another one that imports a layer into that same database). In that case, just select the previous algorithm in the Parent algorithms parameter and the two steps will be executed in the correct order.

Once all the parameters have been assigned valid values, click on [OK] and the algorithm will be added to the canvas. It will be linked to all the other elements in the canvas, whether algorithms or inputs, that provide objects that are used as inputs for that algorithm.

Elements can be dragged to a different position within the canvas, to change the way the module structure is displayed and make it more clear and intuitive. Links between elements are updated automatically. You can zoom in and out by using the mouse wheel.

You can run your algorithm anytime by clicking on the [Run] button. However, in order to use the algorithm from the toolbox, it has to be saved and the modeler dialog closed, to allow the toolbox to refresh its contents.

17.3.3 Saving and loading models

Use the [Save] button to save the current model and the [Open] button to open any model previously saved.

Models are saved with the .model extension. If the model has been previously saved from the modeler window, you will not be prompted for a filename. Since there is already a file associated with that model, the same file will be used for any subsequent saves.

Before saving a model, you have to enter a name and a group for it, using the text boxes in the upper part of the window.

Models saved on the models folder (the default folder when you are prompted for a filename to save the model) will appear in the toolbox in the corresponding branch. When the toolbox is invoked, it searches the models folder for files with the .model extension and loads the models they contain. Since a model is itself an algorithm, it can be added to the toolbox just like any other algorithm.

The models folder can be set from the processing configuration dialog, under the Modeler group.

Models loaded from the models folder appear not only in the toolbox, but also in the algorithms tree in the

Algorithms tab of the modeler window. That means that you can incorporate a model as a part of a bigger model, just as you add any other algorithm.

In some cases, a model might not be loaded because not all the algorithms included in its workflow are available.

If you have used a given algorithm as part of your model, it should be available (that is, it should appear in the toolbox) in order to load that model. Deactivating an algorithm provider in the processing configuration window renders all the algorithms in that provider unusable by the modeler, which might cause problems when loading models. Keep that in mind when you have trouble loading or executing models.

17.3.4 Editing a model

You can edit the model you are currently creating, redefining the workflow and the relationships between the algorithms and inputs that define the model itself.

If you right-click on an algorithm in the canvas representing the model, you will see a context menu like the one shown next:

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Selecting the Remove option will cause the selected algorithm to be removed. An algorithm can be removed only if there are no other algorithms depending on it. That is, if no output from the algorithm is used in a different one as input. If you try to remove an algorithm that has others depending on it, a warning message like the one you can see below will be shown:

Kuva 17.22: Cannot Delete Algorithm

Selecting the Edit option or simply double-clicking on the algorithm icon will show the parameters dialog of the algorithm, so you can change the inputs and parameter values. Not all input elements available in the model will appear in this case as available inputs. Layers or values generated at a more advanced step in the workflow defined by the model will not be available if they cause circular dependencies.

Select the new values and then click on the [OK] button as usual. The connections between the model elements will change accordingly in the modeler canvas.

17.3.5 Editing model help files and meta-information

You can document your models from the modeler itself. Just click on the [Edit model help] button and a dialog like the one shown next will appear.

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On the right-hand side, you will see a simple HTML page, created using the description of the input parameters and outputs of the algorithm, along with some additional items like a general description of the model or its author.

The first time you open the help editor, all these descriptions are empty, but you can edit them using the elements on the left-hand side of the dialog. Select an element on the upper part and then write its description in the text box below.

Model help is saved in a file in the same folder as the model itself. You do not have to worry about saving it, since it is done automatically.

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17.3.6 About available algorithms

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You might notice that some algorithms that can be be executed from the toolbox do not appear in the list of available algorithms when you are designing a model. To be included in a model, an algorithm must have a correct semantic, so as to be properly linked to others in the workflow. If an algorithm does not have such a well-defined semantic (for instance, if the number of output layers cannot be known in advance), then it is not possible to use it within a model, and thus, it does not appear in the list of algorithms that you can find in the modeler dialog.

Additionally, you will see some algorithms in the modeler that are not found in the toolbox. These algorithms are meant to be used exclusively as part of a model, and they are of no interest in a different context. The ‘Calculator’ algorithm is an example of that. It is just a simple arithmetic calculator that you can use to modify numerical values (entered by the user or generated by some other algorithm). This tool is really useful within a model, but outside of that context, it doesn’t make too much sense.

17.4 The batch processing interface

17.4.1 Introduction

All algorithms (including models) can be executed as a batch process. That is, they can be executed using not just a single set of inputs, but several of them, executing the algorithm as many times as needed. This is useful when processing large amounts of data, since it is not necessary to launch the algorithm many times from the toolbox.

To execute an algorithm as a batch process, right-click on its name in the toolbox and select the Execute as batch process option in the pop-up menu that will appear.

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17.4.2 The parameters table

Executing a batch process is similar to performing a single execution of an algorithm. Parameter values have to be defined, but in this case we need not just a single value for each parameter, but a set of them instead, one for each time the algorithm has to be executed. Values are introduced using a table like the one shown next.

Each line of this table represents a single execution of the algorithm, and each cell contains the value of one of the parameters. It is similar to the parameters dialog that you see when executing an algorithm from the toolbox, but with a different arrangement.

By default, the table contains just two rows. You can add or remove rows using the buttons on the lower part of the window.

Once the size of the table has been set, it has to be filled with the desired values.

17.4.3 Filling the parameters table

For most parameters, setting the value is trivial. Just type the value or select it from the list of available options, depending on the parameter type.

The main differences are found for parameters representing layers or tables, and for output file paths. Regarding input layers and tables, when an algorithm is executed as part of a batch process, those input data objects are taken directly from files, and not from the set of them already opened in QGIS. For this reason, any algorithm can be

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Kuva 17.25: Batch Processing executed as a batch process, even if no data objects at all are opened and the algorithm cannot be run from the toolbox.

Filenames for input data objects are introduced directly typing or, more conveniently, clicking on the button on the right hand of the cell, which shows a typical file chooser dialog. Multiple files can be selected at once. If the input parameter represents a single data object and several files are selected, each one of them will be put in a separate row, adding new ones if needed. If the parameter represents a multiple input, all the selected files will be added to a single cell, separated by semicolons (;).

Output data objects are always saved to a file and, unlike when executing an algorithm from the toolbox, saving to a temporary file is not permitted. You can type the name directly or use the file chooser dialog that appears when clicking on the accompanying button.

Once you select the file, a new dialog is shown to allow for autocompletion of other cells in the same column

(same parameter).

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If the default value (‘Do not autocomplete’) is selected, it will just put the selected filename in the selected cell from the parameters table. If any of the other options is selected, all the cells below the selected one will be automatically filled based on a defined criteria. This way, it is much easier to fill the table, and the batch process can be defined with less effort.

Automatic filling can be done by simply adding correlative numbers to the selected file path, or by appending the value of another field at the same row. This is particularly useful for naming output data objects according to input

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17.4.4 Executing the batch process

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To execute the batch process once you have introduced all the necessary values, just click on [OK]. Progress of the global batch task will be shown in the progress bar in the lower part of the dialog.

17.5 Using processing algorithms from the console

The console allows advanced users to increase their productivity and perform complex operations that cannot be performed using any of the other GUI elements of the processing framework. Models involving several algorithms can be defined using the command-line interface, and additional operations such as loops and conditional sentences can be added to create more flexible and powerful workflows.

There is not a proccesing console in QGIS, but all processing commands are available instead from the QGIS built-in Python console. That means that you can incorporate those commands into your console work and connect processing algorithms to all the other features (including methods from the QGIS API) available from there.

The code that you can execute from the Python console, even if it does not call any specific processing method, can be converted into a new algorithm that you can later call from the toolbox, the graphical modeler or any other component, just like you do with any other algorithm. In fact, some algorithms that you can find in the toolbox are simple scripts.

In this section, we will see how to use processing algorithms from the QGIS Python console, and also how to write algorithms using Python.

17.5.1 Calling algorithms from the Python console

The first thing you have to do is to import the processing functions with the following line:

>>> import processing

Now, there is basically just one (interesting) thing you can do with that from the console: execute an algorithm.

That is done using the runalg() method, which takes the name of the algorithm to execute as its first parameter, and then a variable number of additional parameters depending on the requirements of the algorithm. So the first thing you need to know is the name of the algorithm to execute. That is not the name you see in the toolbox, but rather a unique command–line name. To find the right name for your algorithm, you can use the algslist() method. Type the following line in your console:

>>>

processing .

alglist()

You will see something like this.

Accumulated Cost (Anisotropic)---------------->saga:accumulatedcost(anisotropic)

Accumulated Cost (Isotropic)------------------>saga:accumulatedcost(isotropic)

Add Coordinates to points--------------------->saga:addcoordinatestopoints

Add Grid Values to Points--------------------->saga:addgridvaluestopoints

Add Grid Values to Shapes--------------------->saga:addgridvaluestoshapes

Add Polygon Attributes to Points-------------->saga:addpolygonattributestopoints

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Aggregate------------------------------------->saga:aggregate

Aggregate Point Observations------------------>saga:aggregatepointobservations

Aggregation Index----------------------------->saga:aggregationindex

Analytical Hierarchy Process------------------>saga:analyticalhierarchyprocess

Analytical Hillshading------------------------>saga:analyticalhillshading

Average With Mask 1--------------------------->saga:averagewithmask1

Average With Mask 2--------------------------->saga:averagewithmask2

Average With Thereshold 1--------------------->saga:averagewiththereshold1

Average With Thereshold 2--------------------->saga:averagewiththereshold2

Average With Thereshold 3--------------------->saga:averagewiththereshold3

B-Spline Approximation------------------------>saga:b-splineapproximation

...

That’s a list of all the available algorithms, alphabetically ordered, along with their corresponding command-line names.

You can use a string as a parameter for this method. Instead of returning the full list of algorithms, it will only display those that include that string. If, for instance, you are looking for an algorithm to calculate slope from a

DEM, type alglist("slope") to get the following result:

DTM Filter (slope-based)---------------------->saga:dtmfilter(slope-based)

Downslope Distance Gradient------------------->saga:downslopedistancegradient

Relative Heights and Slope Positions---------->saga:relativeheightsandslopepositions

Slope Length---------------------------------->saga:slopelength

Slope, Aspect, Curvature---------------------->saga:slopeaspectcurvature

Upslope Area---------------------------------->saga:upslopearea

Vegetation Index[slope based]----------------->saga:vegetationindex[slopebased]

This result might change depending on the algorithms you have available.

It is easier now to find the algorithm you are looking for and its command-line name, in this case saga:slopeaspectcurvature

.

Once you know the command-line name of the algorithm, the next thing to do is to determine the right syntax to execute it. That means knowing which parameters are needed and the order in which they have to be passed when calling the runalg() method. There is a method to describe an algorithm in detail, which can be used to get a list of the parameters that an algorithm requires and the outputs that it will generate. To get this information, you can use the alghelp(name_of_the_algorithm) method. Use the command-line name of the algorithm, not the full descriptive name.

Calling the method with saga:slopeaspectcurvature as parameter, you get the following description:

>>>

processing .

alghelp( "saga:slopeaspectcurvature" )

ALGORITHM: Slope, Aspect, Curvature

ELEVATION <ParameterRaster>

METHOD <ParameterSelection>

SLOPE <OutputRaster>

ASPECT <OutputRaster>

CURV <OutputRaster>

HCURV <OutputRaster>

VCURV <OutputRaster>

Now you have everything you need to run any algorithm. As we have already mentioned, there is only one single command to execute algorithms: runalg(). Its syntax is as follows:

>>>

processing .

runalg(name_of_the_algorithm, param1, param2, ...

, paramN,

Output1, Output2, ..., OutputN)

The list of parameters and outputs to add depends on the algorithm you want to run, and is exactly the list that the alghelp() method gives you, in the same order as shown.

Depending on the type of parameter, values are introduced differently. The next list gives a quick review of how to introduce values for each type of input parameter:

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• Raster Layer, Vector Layer or Table. Simply use a string with the name that identifies the data object to use

(the name it has in the QGIS Table of Contents) or a filename (if the corresponding layer is not opened, it will be opened but not added to the map canvas). If you have an instance of a QGIS object representing the layer, you can also pass it as parameter. If the input is optional and you do not want to use any data object, use None.

• Selection. If an algorithm has a selection parameter, the value of that parameter should be entered using an integer value. To know the available options, you can use the algoptions() command, as shown in the following example:

>>>

processing .

algoptions( "saga:slopeaspectcurvature" )

METHOD(Method)

0 - [0] Maximum Slope (Travis et al. 1975)

1 - [1] Maximum Triangle Slope (Tarboton 1997)

2 - [2] Least Squares Fitted Plane (Horn 1981, Costa-Cabral & Burgess 1996)

3 - [3] Fit 2.Degree Polynom (Bauer, Rohdenburg, Bork 1985)

4 - [4] Fit 2.Degree Polynom (Heerdegen & Beran 1982)

5 - [5] Fit 2.Degree Polynom (Zevenbergen & Thorne 1987)

6 - [6] Fit 3.Degree Polynom (Haralick 1983)

In this case, the algorithm has one such parameter, with seven options. Notice that ordering is zero-based.

• Multiple input. The value is a string with input descriptors separated by semicolons (;). As in the case of single layers or tables, each input descriptor can be the data object name, or its file path.

• Table Field from XXX. Use a string with the name of the field to use. This parameter is case-sensitive.

• Fixed Table. Type the list of all table values separated by commas (,) and enclosed between quotes (").

Values start on the upper row and go from left to right. You can also use a 2-D array of values representing the table.

• CRS. Enter the EPSG code number of the desired CRS.

• Extent. You must use a string with xmin, xmax, ymin and ymax values separated by commas (,).

Boolean, file, string and numerical parameters do not need any additional explanations.

Input parameters such as strings, booleans, or numerical values have default values. To use them, specify None in the corresponding parameter entry.

For output data objects, type the file path to be used to save it, just as it is done from the toolbox. If you want to save the result to a temporary file, use None. The extension of the file determines the file format. If you enter a file extension not supported by the algorithm, the default file format for that output type will be used, and its corresponding extension appended to the given file path.

Unlike when an algorithm is executed from the toolbox, outputs are not added to the map canvas if you execute that same algorithm from the Python console. If you want to add an output to the map canvas, you have to do it yourself after running the algorithm. To do so, you can use QGIS API commands, or, even easier, use one of the handy methods provided for such tasks.

The runalg method returns a dictionary with the output names (the ones shown in the algorithm description) as keys and the file paths of those outputs as values. You can load those layers by passing the corresponding file paths to the load() method.

17.5.2 Additional functions for handling data

Apart from the functions used to call algorithms, importing the processing package will also import some additional functions that make it easier to work with data, particularly vector data. They are just convenience functions that wrap some functionality from the QGIS API, usually with a less complex syntax. These functions should be used when developing new algorithms, as they make it easier to operate with input data.

Below is a list of some of these commands. More information can be found in the classes under the processing/tools package, and also in the example scripts provided with QGIS.

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• getObject(obj): Returns a QGIS object (a layer or table) from the passed object, which can be a filename or the name of the object in the QGIS Table of Contents.

• values(layer, fields): Returns the values in the attributes table of a vector layer, for the passed fields. Fields can be passed as field names or as zero-based field indices. Returns a dict of lists, with the passed field identifiers as keys. It considers the existing selection.

• features(layer): Returns an iterator over the features of a vector layer, considering the existing selection.

• uniqueValues(layer, field): Returns a list of unique values for a given attribute. Attributes can be passed as a field name or a zero-based field index. It considers the existing selection.

17.5.3 Creating scripts and running them from the toolbox

You can create your own algorithms by writing the corresponding Python code and adding a few extra lines to supply additional information needed to define the semantics of the algorithm. You can find a Create new script menu under the Tools group in the Script algorithms block of the toolbox. Double-click on it to open the script editing dialog. That’s where you should type your code. Saving the script from there in the scripts folder (the default folder when you open the save file dialog) with .py extension will automatically create the corresponding algorithm.

The name of the algorithm (the one you will see in the toolbox) is created from the filename, removing its extension and replacing low hyphens with blank spaces.

Let’s have a look at the following code, which calculates the Topographic Wetness Index (TWI) directly from a

DEM.

##dem=raster

##twi=output ret_slope = processing.runalg("saga:slopeaspectcurvature", dem, 0, None,

None, None, None, None) ret_area = processing.runalg("saga:catchmentarea(mass-fluxmethod)", dem,

0, False, False, False, False, None, None, None, None, None) processing.runalg("saga:topographicwetnessindex(twi), ret_slope[’SLOPE’], ret_area[’AREA’], None, 1, 0, twi)

As you can see, the calculation involves three algorithms, all of them coming from SAGA. The last one calculates the TWI, but it needs a slope layer and a flow accumulation layer. We do not have these layers, but since we have the DEM, we can calculate them by calling the corresponding SAGA algorithms.

The part of the code where this processing takes place is not difficult to understand if you have read the previous sections in this chapter. The first lines, however, need some additional explanation. They provide the information that is needed to turn your code into an algorithm that can be run from any of the GUI components, like the toolbox or the graphical modeler.

These lines start with a double Python comment symbol (##) and have the following structure:

[parameter_name] = [parameter_type] [optional_values]

Here is a list of all the parameter types that are supported in processing scripts, their syntax and some examples.

• raster. A raster layer.

• vector. A vector layer.

• table. A table.

• number. A numerical value. A default value must be provided. For instance, depth=number 2.4.

• string. A text string. As in the case of numerical values, a default value must be added. For instance, name=string Victor

.

• boolean. A boolean value. Add True or False after it to set the default value. For example, verbose=boolean True .

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• multiple raster. A set of input raster layers.

• multiple vector. A set of input vector layers.

• field. A field in the attributes table of a vector layer. The name of the layer has to be added after the field tag. For instance, if you have declared a vector input with mylayer=vector, you could use myfield=field mylayer to add a field from that layer as parameter.

• folder. A folder.

• file. A filename.

The parameter name is the name that will be shown to the user when executing the algorithm, and also the variable name to use in the script code. The value entered by the user for that parameter will be assigned to a variable with that name.

When showing the name of the parameter to the user, the name will be edited to improve its appearance, replacing low hyphens with spaces. So, for instance, if you want the user to see a parameter named A numerical value, you can use the variable name A_numerical_value.

Layers and table values are strings containing the file path of the corresponding object. To turn them into a QGIS object, you can use the processing.getObjectFromUri() function. Multiple inputs also have a string value, which contains the file paths to all selected object, separated by semicolons (;).

Outputs are defined in a similar manner, using the following tags:

• output raster

• output vector

• output table

• output html

• output file

• output number

• output string

The value assigned to the output variables is always a string with a file path. It will correspond to a temporary file path in case the user has not entered any output filename.

When you declare an output, the algorithm will try to add it to QGIS once it is finished. That is why, although the runalg() method does not load the layers it produces, the final TWI layer will be loaded (using the case of our previous example), since it is saved to the file entered by the user, which is the value of the corresponding output.

Do not use the load() method in your script algorithms, just when working with the console line. If a layer is created as output of an algorithm, it should be declared as such. Otherwise, you will not be able to properly use the algorithm in the modeler, since its syntax (as defined by the tags explained above) will not match what the algorithm really creates.

Hidden outputs (numbers and strings) do not have a value. Instead, you have to assign a value to them. To do so, just set the value of a variable with the name you used to declare that output. For instance, if you have used this declaration,

##average=output number the following line will set the value of the output to 5: average = 5

In addition to the tags for parameters and outputs, you can also define the group under which the algorithm will be shown, using the group tag.

If your algorithm takes a long time to process, it is a good idea to inform the user. You have a global named progress available, with two possible methods: setText(text) and setPercentage(percent) to modify the progress text and the progress bar.

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Several examples are provided. Please check them to see real examples of how to create algorithms using the processing framework classes. You can right-click on any script algorithm and select Edit script to edit its code or just to see it.

17.5.4 Documenting your scripts

As in the case of models, you can create additional documentation for your scripts, to explain what they do and how to use them. In the script editing dialog, you will find an [Edit script help] button. Click on it and it will take you to the help editing dialog. Check the section about the graphical modeler to know more about this dialog and how to use it.

Help files are saved in the same folder as the script itself, adding the .help extension to the filename. Notice that you can edit your script’s help before saving the script for the first time. If you later close the script editing dialog without saving the script (i.e., you discard it), the help content you wrote will be lost. If your script was already saved and is associated to a filename, saving the help content is done automatically.

17.5.5 Pre- and post-execution script hooks

Scripts can also be used to set pre- and post-execution hooks that are run before and after an algorithm is run. This can be used to automate tasks that should be performed whenever an algorithm is executed.

The syntax is identical to the syntax explained above, but an additional global variable named alg is available, representing the algorithm that has just been (or is about to be) executed.

.

In the General group of the processing configuration dialog, you will find two entries named Pre-execution script file and Post-execution script file where the filename of the scripts to be run in each case can be entered.

17.6 The history manager

17.6.1 The processing history

Every time you execute an algorithm, information about the process is stored in the history manager. Along with the parameters used, the date and time of the execution are also saved.

This way, it is easy to track and control all the work that has been developed using the processing framework, and easily reproduce it.

The history manager is a set of registry entries grouped according to their date of execution, making it easier to find information about an algorithm executed at any particular moment.

Process information is kept as a command-line expression, even if the algorithm was launched from the toolbox.

This makes it also useful for those learning how to use the command-line interface, since they can call an algorithm using the toolbox and then check the history manager to see how that same algorithm could be called from the command line.

Apart from browsing the entries in the registry, you can also re-execute processes by simply double-clicking on the corresponding entry.

Along with recording algorithm executions, the processing framework communicates with the user by means of the other groups of the registry, namely Errors, Warnings and Information. In case something is not working properly, having a look at the Errors might help you to see what is happening. If you get in contact with a developer to report a bug or error, the information in that group will be very useful for her or him to find out what is going wrong.

Third-party algorithms are usually executed by calling their command-line interfaces, which communicate with the user via the console. Although that console is not shown, a full dump of it is stored in the Information group each time you run one of those algorithms. If, for instance, you are having problems executing a SAGA algorithm,

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Kuva 17.28: History look for an entry named ‘SAGA execution console output’ to check all the messages generated by SAGA and try to find out where the problem is.

Some algorithms, even if they can produce a result with the given input data, might add comments or additional information to the Warning block if they detect potential problems with the data, in order to warn you. Make sure you check those messages if you are having unexpected results.

17.7 Writing new Processing algorithms as python scripts

You can create your own algorithms by writing the corresponding Python code and adding a few extra lines to supply additional information needed to define the semantics of the algorithm. You can find a Create new script menu under the Tools group in the Script algorithms block of the toolbox. Double-click on it to open the script edition dialog. That’s where you should type your code. Saving the script from there in the scripts folder (the default one when you open the save file dialog), with .py extension, will automatically create the corresponding algorithm.

The name of the algorithm (the one you will see in the toolbox) is created from the filename, removing its extension and replacing low hyphens with blank spaces.

Let’s have the following code, which calculates the Topographic Wetness Index (TWI) directly from a DEM

##dem=raster

##twi=output raster ret_slope = processing.runalg("saga:slopeaspectcurvature", dem, 0, None,

None, None, None, None) ret_area = processing.runalg("saga:catchmentarea", dem,

0, False, False, False, False, None, None, None, None, None) processing.runalg("saga:topographicwetnessindextwi, ret_slope[’SLOPE’], ret_area[’AREA’], None, 1, 0, twi)

As you can see, it involves 3 algorithms, all of them coming from SAGA. The last one of them calculates the TWI, but it needs a slope layer and a flow accumulation layer. We do not have these ones, but since we have the DEM,

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we can calculate them calling the corresponding SAGA algorithms.

The part of the code where this processing takes place is not difficult to understand if you have read the previous chapter. The first lines, however, need some additional explanation. They provide the information that is needed to turn your code into an algorithm that can be run from any of the GUI components, like the toolbox or the graphical modeler.

These lines start with a double Python comment symbol (##) and have the following structure

[parameter_name] = [parameter_type] [optional_values]

Here is a list of all the parameter types that are supported in processign scripts, their syntax and some examples.

• raster. A raster layer

• vector. A vector layer

• table. A table

• number. A numerical value. A default value must be provided. For instance, depth=number 2.4

• string. A text string. As in the case of numerical values, a default value must be added. For instance, name=string Victor

• longstring. Same as string, but a larger text box will be shown, so it is better suited for long strings, such as for a script expecting a small code snippet.

• boolean. A boolean value. Add True or False after it to set the default value. For example, verbose=boolean True .

• multiple raster. A set of input raster layers.

• multiple vector. A set of input vector layers.

• field. A field in the attributes table of a vector layer. The name of the layer has to be added after the field tag. For instance, if you have declared a vector input with mylayer=vector, you could use myfield=field mylayer to add a field from that layer as parameter.

• folder. A folder

• file. A filename

• crs. A Coordinate Reference System

The parameter name is the name that will be shown to the user when executing the algorithm, and also the variable name to use in the script code. The value entered by the user for that parameter will be assigned to a variable with that name.

When showing the name of the parameter to the user, the name will be edited it to improve its appearance, replacing low hyphens with spaces. So, for instance, if you want the user to see a parameter named A numerical value, you can use the variable name A_numerical_value.

Layers and tables values are strings containing the filepath of the corresponding object. To turn them into a QGIS object, you can use the processing.getObjectFromUri() function. Multiple inputs also have a string value, which contains the filepaths to all selected objects, separated by semicolons (;).

Outputs are defined in a similar manner, using the following tags:

• output raster

• output vector

• output table

• output html

• output file

• output number

• output string

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• output extent

The value assigned to the output variables is always a string with a filepath. It will correspond to a temporary filepath in case the user has not entered any output filename.

In addition to the tags for parameters and outputs, you can also define the group under which the algorithm will be shown, using the group tag.

The last tag that you can use in your script header is ##nomodeler. Use that when you do not want your algorithm to be shown in the modeler window. This should be used for algorithms that do not have a clear syntax

(for instance, if the number of layers to be created is not known in advance, at design time), which make them unsuitable for the graphical modeler

17.8 Handing data produced by the algorithm

When you declare an output representing a layer (raster, vector or table), the algorithm will try to add it to QGIS once it is finished. That is the reason why, although the runalg() method does not load the layers it produces, the final TWI layer will be loaded, since it is saved to the file entered by the user, which is the value of the corresponding output.

Do not use the load() method in your script algorithms, but just when working with the console line. If a layer is created as output of an algorithm, it should be declared as such. Otherwise, you will not be able to properly use the algorithm in the modeler, since its syntax (as defined by the tags explained above) will not match what the algorithm really creates.

Hidden outputs (numbers and strings) do not have a value. Instead, it is you who has to assign a value to them. To do so, just set the value of a variable with the name you used to declare that output. For instance, if you have used this declaration,

##average=output number the following line will set the value of the output to 5: average = 5

17.9 Communicating with the user

If your algorithm takes a long time to process, it is a good idea to inform the user. You have a global named progress available, with two available methods: setText(text) and setPercentage(percent) to modify the progress text and the progress bar.

If you have to provide some information to the user, not related to the progress of the algorithm, you can use the setInfo(text) method, also from the progress object.

If your script has some problem, the correct way of propagating it is to raise an exception of type

GeoAlgorithmExecutionException() . You can pass a message as argument to the constructor of the exception. Processing will take care of handling it and communicating with the user, depending on where the algorithm is being executed from (toolbox, modeler, Python console...)

17.10 Documenting your scripts

As in the case of models, you can create additional documentation for your script, to explain what they do and how to use them. In the script editing dialog you will find a [Edit script help] button. Click on it and it will take you to the help editing dialog. Check the chapter about the graphical modeler to know more about this dialog and how to use it.

Help files are saved in the same folder as the script itself, adding the .help extension to the filename. Notice that you can edit your script’s help before saving it for the first time. If you later close the script editing dialog without

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saving the script (i.e. you discard it), the help content you wrote will be lost. If your script was already saved and is associated to a filename, saving is done automatically.

17.11 Example scripts

Several examples are available in the on-line collection of scripts, which you can access by selecting the Get script from on-line script collection tool under the Scripts/tools entry in the toolbox.

Please, check them to see real examples of how to create algorithms using the processing framework classes. You can right-click on any script algorithm and select Edit script to edit its code or just to see it.

17.12 Best practices for writing script algorithms

Here’s a quick summary of ideas to consider when creating your script algorithms and, epsecially, if you want to share with other QGIS users. Following these simple rules will ensure consistency across the different Processing elements such as the toolbox, the modeler or the batch processing interface.

• Do not load resulting layers. Let Processing handle your results and load your layers if needed.

• Always declare the outputs your algorithm creates. Avoid things such as decalring one output and then using the destination filename set for that output to create a collection of them. That will break the correct semantics of the algorithm and make it impossible to use it safely in the modeler. If you have to write an algorithm like that, make sure you add the ##nomodeler tag.

• Do not show message boxes or use any GUI element from the script. If you want to communicate with the user, use the setInfo() method or throw an GeoAlgorithmExecutionException

• As a rule of thumb, do not forget that your agorithm might be executed in a context other than the Processing toolbox.

17.13 Pre- and post-execution script hooks

Scripts can also be used to set pre- and post-execution hooks that are run before and after an algorithm is run. This can be used to automate tasks that should be performed whenever an algorithm is executed.

The syntax is identical to the syntax explained above, but an additional global variable named alg is available, representing the algorithm that has just been (or is about to be) executed.

.

In the General group of the processing config dialog you will find two entries named Pre-execution script file and

Post-execution script file where the filename of the scripts to be run in each case can be entered.

17.14 Configuring external applications

The processing framework can be extended using additional applications. Currently, SAGA, GRASS, OTB (Orfeo

Toolbox) and R are supported, along with some other command-line applications that provide spatial data analysis functionalities. Algorithms relying on an external application are managed by their own algorithm provider.

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This section will show you how to configure the processing framework to include these additional applications, and it will explain some particular features of the algorithms based on them. Once you have correctly configured the system, you will be able to execute external algorithms from any component like the toolbox or the graphical modeler, just like you do with any other geoalgorithm.

By default, all algorithms that rely on an external appplication not shipped with QGIS are not enabled. You can enable them in the configuration dialog. Make sure that the corresponding application is already installed in your system. Enabling an algorithm provider without installing the application it needs will cause the algorithms to appear in the toolbox, but an error will be thrown when you try to execute them.

This is because the algorithm descriptions (needed to create the parameters dialog and provide the information needed about the algorithm) are not included with each application, but with QGIS instead. That is, they are part of QGIS, so you have them in your installation even if you have not installed any other software. Running the algorithm, however, needs the application binaries to be installed in your system.

17.14.1 A note for Windows users

If you are not an advanced user and you are running QGIS on Windows, you might not be interested in reading the rest of this chapter. Make sure you install QGIS in your system using the standalone installer. That will automatically install SAGA, GRASS and OTB in your system and configure them so they can be run from QGIS.

All the algorithms in the simplified view of the toolbox will be ready to be run without needing any further configuration. If installing through OSGeo4W application, make sure you select for insttallation SAGA and OTB as well.

If you want to know more about how these providers work, or if you want to use some algorithms not included in the simplified toolbox (such as R scripts), keep on reading.

17.14.2 A note on file formats

When using an external software, opening a file in QGIS does not mean that it can be opened and processed as well in that other software. In most cases, other software can read what you have opened in QGIS, but in some cases, that might not be true. When using databases or uncommon file formats, whether for raster or vector layers, problems might arise. If that happens, try to use well-known file formats that you are sure are understood by both programs, and check the console output (in the history and log dialog) to know more about what is going wrong.

Using GRASS raster layers is, for instance, one case in which you might have trouble and not be able to complete your work if you call an external algorithm using such a layer as input. For this reason, these layers will not appear as available to algorithms.

You should, however, find no problems at all with vector layers, since QGIS automatically converts from the original file format to one accepted by the external application before passing the layer to it. This adds extra processing time, which might be significant if the layer has a large size, so do not be surprised if it takes more time to process a layer from a DB connection than it does to process one of a similar size stored in a shapefile.

Providers not using external applications can process any layer that you can open in QGIS, since they open it for analysis through QGIS.

Regarding output formats, all formats supported by QGIS as output can be used, both for raster and vector layers.

Some providers do not support certain formats, but all can export to common raster layer formats that can later be transformed by QGIS automatically. As in the case of input layers, if this conversion is needed, that might increase the processing time.

If the extension of the filename specified when calling an algorithm does not match the extension of any of the formats supported by QGIS, then a suffix will be added to set a default format. In the case of raster layers, the

.tif

extension is used, while .shp is used for vector layers.

17.14.3 A note on vector layer selections

External applications may also be made aware of the selections that exist in vector layers within QGIS. However, that requires rewriting all input vector layers, just as if they were originally in a format not supported by the

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external application. Only when no selection exists, or the Use only selected features option is not enabled in the processing general configuration, can a layer be directly passed to an external application.

In other cases, exporting only selected features is needed, which causes execution times to be longer.

SAGA

SAGA algorithms can be run from QGIS if you have SAGA installed in your system and you configure the processing framework properly so it can find SAGA executables. In particular, the SAGA command-line executable is needed to run SAGA algorithms.

If you are running Windows, both the stand-alone installer and the OSGeo4W installer include SAGA along with

QGIS, and the path is automatically configured, so there is no need to do anything else.

If you have installed SAGA yourself (remember, you need version 2.1), the path to the SAGA executable must be configured. To do this, open the configuration dialog. In the SAGA block, you will find a setting named SAGA

Folder

. Enter the path to the folder where SAGA is installed. Close the configuration dialog, and now you are ready to run SAGA algorithms from QGIS.

If you are running Linux, SAGA binaries are not included with SEXTANTE, so you have to download and install the software yourself. Please check the SAGA website for more information. SAGA 2.1 is needed.

In this case, there is no need to configure the path to the SAGA executable, and you will not see those folders.

Instead, you must make sure that SAGA is properly installed and its folder is added to the PATH environment variable. Just open a console and type saga_cmd to check that the system can find where the SAGA binaries are located.

17.14.4 About SAGA grid system limitations

Most SAGA algorithms that require several input raster layers require them to have the same grid system. That is, they must cover the same geographic area and have the same cell size, so their corresponding grids match. When calling SAGA algorithms from QGIS, you can use any layer, regardless of its cell size and extent. When multiple raster layers are used as input for a SAGA algorithm, QGIS resamples them to a common grid system and then passes them to SAGA (unless the SAGA algorithm can operate with layers from different grid systems).

The definition of that common grid system is controlled by the user, and you will find several parameters in the

SAGA group of the settings window to do so. There are two ways of setting the target grid system:

• Setting it manually. You define the extent by setting the values of the following parameters:

– Resampling min X

– Resampling max X

– Resampling min Y

– Resampling max Y

– Resampling cellsize

Notice that QGIS will resample input layers to that extent, even if they do not overlap with it.

• Setting it automatically from input layers. To select this option, just check the Use min covering grid system for resampling option. All the other settings will be ignored and the minimum extent that covers all the input layers will be used. The cell size of the target layer is the maximum of all cell sizes of the input layers.

For algorithms that do not use multiple raster layers, or for those that do not need a unique input grid system, no resampling is performed before calling SAGA, and those parameters are not used.

17.14.5 Limitations for multi-band layers

Unlike QGIS, SAGA has no support for multi-band layers. If you want to use a multiband layer (such as an RGB or multispectral image), you first have to split it into single-banded images. To do so, you can use the ‘SAGA/Grid

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- Tools/Split RGB image’ algorithm (which creates three images from an RGB image) or the ‘SAGA/Grid -

Tools/Extract band’ algorithm (to extract a single band).

17.14.6 Limitations in cell size

SAGA assumes that raster layers have the same cell size in the X and Y axis. If you are working with a layer with different values for horizontal and vertical cell size, you might get unexpected results. In this case, a warning will be added to the processing log, indicating that an input layer might not be suitable to be processed by SAGA.

17.14.7 Logging

When QGIS calls SAGA, it does so using its command-line interface, thus passing a set of commands to perform all the required operations. SAGA shows its progress by writing information to the console, which includes the percentage of processing already done, along with additional content. This output is filtered and used to update the progress bar while the algorithm is running.

Both the commands sent by QGIS and the additional information printed by SAGA can be logged along with other processing log messages, and you might find them useful to track in detail what is going on when QGIS runs a

SAGA algorithm. You will find two settings, namely Log console output and Log execution commands, to activate that logging mechanism.

Most other providers that use an external application and call it through the command-line have similar options, so you will find them as well in other places in the processing settings list.

R. Creating R scripts

R integration in QGIS is different from that of SAGA in that there is not a predefined set of algorithms you can run

(except for a few examples). Instead, you should write your scripts and call R commands, much like you would do from R, and in a very similar manner to what we saw in the section dedicated to processing scripts. This section shows you the syntax to use to call those R commands from QGIS and how to use QGIS objects (layers, tables) in them.

The first thing you have to do, as we saw in the case of SAGA, is to tell QGIS where your R binaries are located.

You can do this using the R folder entry in the processing configuration dialog. Once you have set that parameter, you can start creating and executing your own R scripts.

Once again, this is different in Linux, and you just have to make sure that the R folder is included in the PATH environment variable. If you can start R just typing R in a console, then you are ready to go.

To add a new algorithm that calls an R function (or a more complex R script that you have developed and you would like to have available from QGIS), you have to create a script file that tells the processing framework how to perform that operation and the corresponding R commands to do so.

R script files have the extension .rsx, and creating them is pretty easy if you just have a basic knowledge of R syntax and R scripting. They should be stored in the R scripts folder. You can set this folder in the R settings group

(available from the processing settings dialog), just like you do with the folder for regular processing scripts.

Let’s have a look at a very simple script file, which calls the R method spsample to create a random grid within the boundary of the polygons in a given polygon layer. This method belongs to the maptools package. Since almost all the algorithms that you might like to incorporate into QGIS will use or generate spatial data, knowledge of spatial packages like maptools and, especially, sp, is mandatory.

##polyg=vector

##numpoints=number 10

##output=output vector

##sp=group pts=spsample(polyg,numpoints,type="random") output=SpatialPointsDataFrame(pts, as.data.frame(pts))

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The first lines, which start with a double Python comment sign (##), tell QGIS the inputs of the algorithm described in the file and the outputs that it will generate. They work with exactly the same syntax as the SEXTANTE scripts that we have already seen, so they will not be described here again.

When you declare an input parameter, QGIS uses that information for two things: creating the user interface to ask the user for the value of that parameter and creating a corresponding R variable that can later be used as input for R commands.

In the above example, we are declaring an input of type vector named polyg. When executing the algorithm,

QGIS will open in R the layer selected by the user and store it in a variable also named polyg. So, the name of a parameter is also the name of the variable that we can use in R for accesing the value of that parameter (thus, you should avoid using reserved R words as parameter names).

Spatial elements such as vector and raster layers are read using the readOGR() and brick() commands (you do not have to worry about adding those commands to your description file – QGIS will do it), and they are stored as Spatial*DataFrame objects. Table fields are stored as strings containing the name of the selected field.

Tables are opened using the read.csv() command. If a table entered by the user is not in CSV format, it will be converted prior to importing it into R.

Additionally, raster files can be read using the readGDAL() command instead of brick() by using the

##usereadgdal .

If you are an advanced user and do not want QGIS to create the object representing the layer, you can use the

##passfilename tag to indicate that you prefer a string with the filename instead. In this case, it is up to you to open the file before performing any operation on the data it contains.

With the above information, we can now understand the first line of our first example script (the first line not starting with a Python comment).

pts = spsample(polyg,numpoints, type = "random" )

The variable polygon already contains a SpatialPolygonsDataFrame object, so it can be used to call the spsample method, just like the numpoints one, which indicates the number of points to add to the created sample grid.

Since we have declared an output of type vector named out, we have to create a variable named out and store a

Spatial*DataFrame object in it (in this case, a SpatialPointsDataFrame). You can use any name for your intermediate variables. Just make sure that the variable storing your final result has the same name that you used to declare it, and that it contains a suitable value.

In this case, the result obtained from the spsample method has to be converted explicitly into a

SpatialPointsDataFrame object, since it is itself an object of class ppp, which is not a suitable class to be returned to QGIS.

If your algorithm generates raster layers, the way they are saved will depend on whether or not you have used the

#dontuserasterpackage option. In you have used it, layers are saved using the writeGDAL() method. If not, the writeRaster() method from the raster package will be used.

If you have used the #passfilename option, outputs are generated using the raster package (with writeRaster()

), even though it is not used for the inputs.

If your algorithm does not generate any layer, but rather a text result in the console instead, you have to indicate that you want the console to be shown once the execution is finished. To do so, just start the command lines that produce the results you want to print with the > (‘greater’) sign. The output of all other lines will not be shown.

For instance, here is the description file of an algorithm that performs a normality test on a given field (column) of the attributes of a vector layer:

##layer=vector

##field=field layer

##nortest=group library(nortest)

>lillie.test(layer[[field]])

The output of the last line is printed, but the output of the first is not (and neither are the outputs from other command lines added automatically by QGIS).

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If your algorithm creates any kind of graphics (using the plot() method), add the following line:

##showplots

This will cause QGIS to redirect all R graphical outputs to a temporary file, which will be opened once R execution has finished.

Both graphics and console results will be shown in the processing results manager.

For more information, please check the script files provided with SEXTANTE. Most of them are rather simple and will greatly help you understand how to create your own scripts.

Muista: rgdal and maptools libraries are loaded by default, so you do not have to add the corresponding library() commands (you just have to make sure that those two packages are installed in your R distribution).

However, other additional libraries that you might need have to be explicitly loaded. Just add the necessary commands at the beginning of your script. You also have to make sure that the corresponding packages are installed in the R distribution used by QGIS. The processing framework will not take care of any package installation. If you run a script that requires a package that is not installed, the execution will fail, and SEXTANTE will try to detect which packages are missing. You must install those missing libraries manually before you can run the algorithm.

GRASS

Configuring GRASS is not much different from configuring SAGA. First, the path to the GRASS folder has to be defined, but only if you are running Windows. Additionaly, a shell interpreter (usually msys.exe, which can be found in most GRASS for Windows distributions) has to be defined and its path set up as well.

By default, the processing framework tries to configure its GRASS connector to use the GRASS distribution that ships along with QGIS. This should work without problems in most systems, but if you experience problems, you might have to configure the GRASS connector manually. Also, if you want to use a different GRASS installation, you can change that setting and point to the folder where the other version is installed. GRASS 6.4 is needed for algorithms to work correctly.

If you are running Linux, you just have to make sure that GRASS is correctly installed, and that it can be run without problem from a console.

GRASS algorithms use a region for calculations. This region can be defined manually using values similar to the ones found in the SAGA configuration, or automatically, taking the minimum extent that covers all the input layers used to execute the algorithm each time. If the latter approach is the behaviour you prefer, just check the Use min covering region option in the GRASS configuration parameters.

The last parameter that has to be configured is related to the mapset. A mapset is needed to run GRASS, and the processing framework creates a temporary one for each execution. You have to specify if the data you are working with uses geographical (lat/lon) coordinates or projected ones.

GDAL

No additional configuration is needed to run GDAL algorithms. Since they are already incorporated into QGIS, the algorithms can infer their configuration from it.

Orfeo Toolbox

Orfeo Toolbox (OTB) algorithms can be run from QGIS if you have OTB installed in your system and you have configured QGIS properly, so it can find all necessary files (command-line tools and libraries).

As in the case of SAGA, OTB binaries are included in the stand-alone installer for Windows, but they are not included if you are runing Linux, so you have to download and install the software yourself. Please check the OTB website for more information.

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Once OTB is installed, start QGIS, open the processing configuration dialog and configure the OTB algorithm provider. In the Orfeo Toolbox (image analysis) block, you will find all settings related to OTB. First, ensure that algorithms are enabled.

Then, configure the path to the folder where OTB command-line tools and libraries are installed:

• Usually OTB applications folder points to /usr/lib/otb/applications and OTB command line tools folder is /usr/bin.

• If you use the OSGeo4W installer, then install otb-bin package and enter

C:\OSGeo4W\apps\orfeotoolbox\applications as OTB applications folder and

C:\OSGeo4W\bin as OTB command line tools folder. These values should be configured by default, but if you have a different OTB installation, configure them to the corresponding values in your system.

TauDEM

To use this provider, you need to install TauDEM command line tools.

17.14.8 Windows

Please visit the TauDEM homepage for installation instructions and precompiled binaries for 32-bit and 64-bit systems. IMPORTANT: You need TauDEM 5.0.6 executables. Version 5.2 is currently not supported.

17.14.9 Linux

There are no packages for most Linux distributions, so you should compile TauDEM by yourself. As TauDEM uses MPICH2, first install it using your favorite package manager. Alternatively, TauDEM works fine with Open

MPI, so you can use it instead of MPICH2.

Download TauDEM 5.0.6

source code and extract the files in some folder.

Open the linearpart.h file, and after line

#include "mpi.h" add a new line with

#include <stdint.h> so you’ll get

#include "mpi.h"

#include <stdint.h>

Save the changes and close the file. Now open tiffIO.h, find line #include "stdint.h" and replace quotes () with <>, so you’ll get

#include <stdint.h>

Save the changes and close the file. Create a build directory and cd into it mkdir build cd build

Configure your build with the command

CXX=mpicxx cmake -DCMAKE_INSTALL_PREFIX=/usr/local ..

and then compile

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make

.

Finally, to install TauDEM into /usr/local/bin, run sudo make install

17.15 The QGIS Commander

Processing includes a practical tool that allows you to run algorithms without having to use the toolbox, but just by typing the name of the algorithm you want to run.

This tool is known as the QGIS commander, and it is just a simple text box with autocompletion where you type the command you want to run.

Kuva 17.29: The QGIS Commander

The Commander is started from the Analysis menu or, more practically, by pressing Shift + Ctrl + M (you can change that default keyboard shortcut in the QGIS configuration if you prefer a different one). Apart from executing Processing algorithms, the Commander gives you access to most of the functionality in QGIS, which means that it gives you a practical and efficient way of running QGIS tasks and allows you to control QGIS with reduced usage of buttons and menus.

Moreover, the Commander is configurable, so you can add your custom commands and have them just a few keystrokes away, making it a powerful tool to help you become more productive in your daily work with QGIS.

17.15.1 Available commands

The commands available in the Commander fall in the following categories:

• Processing algorithms.

These are shown as Processing algorithm: <name of the algorithm>

.

• Menu items. These are shown as Menu item: <menu entry text>. All menus items available from the QGIS interface are available, even if they are included in a submenu.

• Python functions. You can create short Python functions that will be then included in the list of available commands. They are shown as Function: <function name>.

To run any of the above, just start typing and then select the corresponding element from the list of available commands that appears after filtering the whole list of commands with the text you have entered.

In the case of calling a Python function, you can select the entry in the list, which is prefixed by

Function:

(for instance, Function: removeall), or just directly type the function name (‘‘removeall in the previous example). There is no need to add brackets after the function name.

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17.15.2 Creating custom functions

Custom functions are added by entering the corresponding Python code in the commands.py file that is found in the .qgis/sextante/commander directory in your user folder. It is just a simple Python file where you can add the functions that you need.

The file is created with a few example functions the first time you open the Commander. If you haven’t launched the Commander yet, you can create the file yourself. To edit the commands file, use your favorite text editor. You can also use a built-in editor by calling the edit command from the Commander. It will open the editor with the commands file, and you can edit it directly and then save your changes.

For instance, you can add the following function, which removes all layers:

from qgis.gui

import

*

def

removeall (): mapreg = QgsMapLayerRegistry .

instance() mapreg .

removeAllMapLayers()

Once you have added the function, it will be available in the Commander, and you can invoke it by typing removeall

. There is no need to do anything apart from writing the function itself.

Functions can receive parameters. Add *args to your function definition to receive arguments. When calling the function from the Commander, parameters have to be passed separated by spaces.

Here is an example of a function that loads a layer and takes a parameter with the filename of the layer to load.

import processing def

load (

* args): processing .

load(args[ 0 ])

.

If you want to load the layer in /home/myuser/points.shp, type load /home/myuser/points.shp

in the Commander text box.

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18

Processing providers and algorithms

.

18.1 GDAL algorithm provider

.

GDAL (Geospatial Data Abstraction Library) is a translator library for raster and vector geospatial data formats.

18.1.1 GDAL analysis

Aspect

Description

<put algortithm description here>

Parameters

Input layer

[raster] <put parameter description here>

Band number

[number] <put parameter description here>

Default: 1

Compute edges

[boolean] <put parameter description here>

Default: False

Use Zevenbergen&Thorne formula (instead of the Horn’s one)

[boolean] <put parameter description here>

Default: False

Return trigonometric angle (instead of azimuth)

[boolean] <put parameter description here>

Default: False

Return o for flat (instead of -9999)

[boolean] <put parameter description here>

Default: False

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Outputs

Output file

[raster] <put output description here>

Console usage

processing .

runalg( ’gdalogr:aspect’ , input , band, compute_edges, zevenbergen, trig_angle, zero_flat, output)

See also

Color relief

Description

<put algortithm description here>

Parameters

Input layer

[raster] <put parameter description here>

Band number

[number] <put parameter description here>

Default: 1

Compute edges

[boolean] <put parameter description here>

Default: False

Color configuration file

[file] <put parameter description here>

Matching mode

[selection] <put parameter description here>

Options:

• 0 — “0,0,0,0” RGBA

• 1 — Exact color

• 2 — Nearest color

Default: 0

Outputs

Output file

[raster] <put output description here>

Console usage

processing .

runalg( ’gdalogr:colorrelief’ , input , band, compute_edges, color_table, match_mode, output)

See also

Fill nodata

Description

<put algortithm description here>

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Parameters

Input layer

[raster] <put parameter description here>

Search distance

[number] <put parameter description here>

Default: 100

Smooth iterations

[number] <put parameter description here>

Default: 0

Band to operate on

[number] <put parameter description here>

Default: 1

Validity mask

[raster] Optional.

<put parameter description here>

Do not use default validity mask

[boolean] <put parameter description here>

Default: False

Outputs

Output layer

[raster] <put output description here>

Console usage

processing .

runalg( ’gdalogr:fillnodata’ , input , distance, iterations, band, mask, no_default_mask, output)

See also

Grid (Moving average)

Description

<put algortithm description here>

Parameters

Input layer

[vector: point] <put parameter description here>

Z field

[tablefield: numeric] Optional.

<put parameter description here>

Radius 1

[number] <put parameter description here>

Default: 0.0

Radius 2

[number] <put parameter description here>

Default: 0.0

Min points

[number] <put parameter description here>

Default: 0.0

Angle

[number] <put parameter description here>

Default: 0.0

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Nodata

[number] <put parameter description here>

Default: 0.0

Output raster type

[selection] <put parameter description here>

Options:

• 0 — Byte

• 1 — Int16

• 2 — UInt16

• 3 — UInt32

• 4 — Int32

• 5 — Float32

• 6 — Float64

• 7 — CInt16

• 8 — CInt32

• 9 — CFloat32

• 10 — CFloat64

Default: 5

Outputs

Output file

[raster] <put output description here>

Console usage

processing .

runalg( ’gdalogr:gridaverage’ , input , z_field, radius_1, radius_2, min_points, angle, nodata, rtype, output)

See also

Grid (Data metrics)

Description

<put algortithm description here>

Parameters

Input layer

[vector: point] <put parameter description here>

Z field

[tablefield: numeric] Optional.

<put parameter description here>

Metrics

[selection] <put parameter description here>

Options:

• 0 — Minimum

• 1 — Maximum

• 2 — Range

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• 3 — Count

• 4 — Average distance

• 5 — Average distance between points

Default: 0

Radius 1

[number] <put parameter description here>

Default: 0.0

Radius 2

[number] <put parameter description here>

Default: 0.0

Min points

[number] <put parameter description here>

Default: 0.0

Angle

[number] <put parameter description here>

Default: 0.0

Nodata

[number] <put parameter description here>

Default: 0.0

Output raster type

[selection] <put parameter description here>

Options:

• 0 — Byte

• 1 — Int16

• 2 — UInt16

• 3 — UInt32

• 4 — Int32

• 5 — Float32

• 6 — Float64

• 7 — CInt16

• 8 — CInt32

• 9 — CFloat32

• 10 — CFloat64

Default: 5

Outputs

Output file

[raster] <put output description here>

Console usage

processing .

runalg( ’gdalogr:griddatametrics’ , input , z_field, metric, radius_1, radius_2, min_points, angle, nodata, rtype, output)

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See also

Grid (Inverse distance to a power)

Description

<put algortithm description here>

Parameters

Input layer

[vector: point] <put parameter description here>

Z field

[tablefield: numeric] Optional.

<put parameter description here>

Power

[number] <put parameter description here>

Default: 2.0

Smothing

[number] <put parameter description here>

Default: 0.0

Radius 1

[number] <put parameter description here>

Default: 0.0

Radius 2

[number] <put parameter description here>

Default: 0.0

Max points

[number] <put parameter description here>

Default: 0.0

Min points

[number] <put parameter description here>

Default: 0.0

Angle

[number] <put parameter description here>

Default: 0.0

Nodata

[number] <put parameter description here>

Default: 0.0

Output raster type

[selection] <put parameter description here>

Options:

• 0 — Byte

• 1 — Int16

• 2 — UInt16

• 3 — UInt32

• 4 — Int32

• 5 — Float32

• 6 — Float64

• 7 — CInt16

• 8 — CInt32

• 9 — CFloat32

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• 10 — CFloat64

Default: 5

Outputs

Output file

[raster] <put output description here>

Console usage

processing .

runalg( ’gdalogr:gridinvdist’ , input , z_field, power, smothing, radius_1, radius_2, max_points, min_points, angle, nodata, rtype, output)

See also

Grid (Nearest neighbor)

Description

<put algortithm description here>

Parameters

Input layer

[vector: point] <put parameter description here>

Z field

[tablefield: numeric] Optional.

<put parameter description here>

Radius 1

[number] <put parameter description here>

Default: 0.0

Radius 2

[number] <put parameter description here>

Default: 0.0

Angle

[number] <put parameter description here>

Default: 0.0

Nodata

[number] <put parameter description here>

Default: 0.0

Output raster type

[selection] <put parameter description here>

Options:

• 0 — Byte

• 1 — Int16

• 2 — UInt16

• 3 — UInt32

• 4 — Int32

• 5 — Float32

• 6 — Float64

• 7 — CInt16

• 8 — CInt32

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• 9 — CFloat32

• 10 — CFloat64

Default: 5

Outputs

Output file

[raster] <put output description here>

Console usage

processing .

runalg( ’gdalogr:gridnearestneighbor’ , input , z_field, radius_1, radius_2, angle, nodata, rtype, output)

See also

Hillshade

Description

<put algortithm description here>

Parameters

Input layer

[raster] <put parameter description here>

Band number

[number] <put parameter description here>

Default: 1

Compute edges

[boolean] <put parameter description here>

Default: False

Use Zevenbergen&Thorne formula (instead of the Horn’s one)

[boolean] <put parameter description here>

Default: False

Z factor (vertical exaggeration)

[number] <put parameter description here>

Default: 1.0

Scale (ratio of vert. units to horiz.)

[number] <put parameter description here>

Default: 1.0

Azimuth of the light

[number] <put parameter description here>

Default: 315.0

Altitude of the light

[number] <put parameter description here>

Default: 45.0

Outputs

Output file

[raster] <put output description here>

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Console usage

processing .

runalg( ’gdalogr:hillshade’ , input , band, compute_edges, zevenbergen, z_factor, scale, azimuth, altitude, output)

See also

Near black

Description

<put algortithm description here>

Parameters

Input layer

[raster] <put parameter description here>

How far from black (white)

[number] <put parameter description here>

Default: 15

Search for nearly white pixels instead of nearly black

[boolean] <put parameter description here>

Default: False

Outputs

Output layer

[raster] <put output description here>

Console usage

processing .

runalg( ’gdalogr:nearblack’ , input , near, white, output)

See also

Proximity (raster distance)

Description

<put algortithm description here>

Parameters

Input layer

[raster] <put parameter description here>

Values

[string] <put parameter description here>

Default: (not set)

Dist units

[selection] <put parameter description here>

Options:

• 0 — GEO

• 1 — PIXEL

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Default: 0

Max dist (negative value to ignore)

[number] <put parameter description here>

Default: -1

No data (negative value to ignore)

[number] <put parameter description here>

Default: -1

Fixed buf val (negative value to ignore)

[number] <put parameter description here>

Default: -1

Output raster type

[selection] <put parameter description here>

Options:

• 0 — Byte

• 1 — Int16

• 2 — UInt16

• 3 — UInt32

• 4 — Int32

• 5 — Float32

• 6 — Float64

• 7 — CInt16

• 8 — CInt32

• 9 — CFloat32

• 10 — CFloat64

Default: 5

Outputs

Output layer

[raster] <put output description here>

Console usage

processing .

runalg( ’gdalogr:proximity’ , input , values, units, max_dist, nodata, buf_val, rtype, output)

See also

Roughness

Description

<put algortithm description here>

Parameters

Input layer

[raster] <put parameter description here>

Band number

[number] <put parameter description here>

Default: 1

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Compute edges

[boolean] <put parameter description here>

Default: False

Outputs

Output file

[raster] <put output description here>

Console usage

processing .

runalg( ’gdalogr:roughness’ , input , band, compute_edges, output)

See also

Sieve

Description

<put algortithm description here>

Parameters

Input layer

[raster] <put parameter description here>

Threshold

[number] <put parameter description here>

Default: 2

Pixel connection

[selection] <put parameter description here>

Options:

• 0 — 4

• 1 — 8

Default: 0

Outputs

Output layer

[raster] <put output description here>

Console usage

processing .

runalg( ’gdalogr:sieve’ , input , threshold, connections, output)

See also

Slope

Description

<put algortithm description here>

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Parameters

Input layer

[raster] <put parameter description here>

Band number

[number] <put parameter description here>

Default: 1

Compute edges

[boolean] <put parameter description here>

Default: False

Use Zevenbergen&Thorne formula (instead of the Horn’s one)

[boolean] <put parameter description here>

Default: False

Slope expressed as percent (instead of degrees)

[boolean] <put parameter description here>

Default: False

Scale (ratio of vert. units to horiz.)

[number] <put parameter description here>

Default: 1.0

Outputs

Output file

[raster] <put output description here>

Console usage

processing .

runalg( ’gdalogr:slope’ , input , band, compute_edges, zevenbergen, as_percent, scale, output)

See also

TPI (Topographic Position Index)

Description

<put algortithm description here>

Parameters

Input layer

[raster] <put parameter description here>

Band number

[number] <put parameter description here>

Default: 1

Compute edges

[boolean] <put parameter description here>

Default: False

Outputs

Output file

[raster] <put output description here>

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Console usage

processing .

runalg( ’gdalogr:tpitopographicpositionindex’ , input , band, compute_edges, output)

See also

TRI (Terrain Ruggedness Index)

Description

<put algortithm description here>

Parameters

Input layer

[raster] <put parameter description here>

Band number

[number] <put parameter description here>

Default: 1

Compute edges

[boolean] <put parameter description here>

Default: False

Outputs

Output file

[raster] <put output description here>

Console usage

processing .

runalg( ’gdalogr:triterrainruggednessindex’ , input , band, compute_edges, output)

.

See also

18.1.2 GDAL conversion gdal2xyz

Description

<put algortithm description here>

Parameters

Input layer

[raster] <put parameter description here>

Band number

[number] <put parameter description here>

Default: 1

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Outputs

Output file

[table] <put output description here>

Console usage

processing .

runalg( ’gdalogr:gdal2xyz’ , input , band, output)

See also

PCT to RGB

Description

<put algortithm description here>

Parameters

Input layer

[raster] <put parameter description here>

Band to convert

[selection] <put parameter description here>

Options:

• 0 — 1

• 1 — 2

• 2 — 3

• 3 — 4

• 4 — 5

• 5 — 6

• 6 — 7

• 7 — 8

• 8 — 9

• 9 — 10

• 10 — 11

• 11 — 12

• 12 — 13

• 13 — 14

• 14 — 15

• 15 — 16

• 16 — 17

• 17 — 18

• 18 — 19

• 19 — 20

• 20 — 21

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• 21 — 22

• 22 — 23

• 23 — 24

• 24 — 25

Default: 0

Outputs

Output layer

[raster] <put output description here>

Console usage

processing .

runalg( ’gdalogr:pcttorgb’ , input , nband, output)

See also

Polygonize (raster to vector)

Description

<put algortithm description here>

Parameters

Input layer

[raster] <put parameter description here>

Output field name

[string] <put parameter description here>

Default: DN

Outputs

Output layer

[vector] <put output description here>

Console usage

processing .

runalg( ’gdalogr:polygonize’ , input , field, output)

See also

Rasterize (vector to raster)

Description

<put algortithm description here>

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Parameters

Input layer

[vector: any] <put parameter description here>

Attribute field

[tablefield: any] <put parameter description here>

Write values inside an existing raster layer(*) [boolean] <put parameter description here>

Default: False

Set output raster size (ignored if above option is checked)

[selection] <put parameter description here>

Options:

• 0 — Output size in pixels

• 1 — Output resolution in map units per pixel

Default: 1

Horizontal

[number] <put parameter description here>

Default: 100.0

Vertical

[number] <put parameter description here>

Default: 100.0

Raster type

[selection] <put parameter description here>

Options:

• 0 — Byte

• 1 — Int16

• 2 — UInt16

• 3 — UInt32

• 4 — Int32

• 5 — Float32

• 6 — Float64

• 7 — CInt16

• 8 — CInt32

• 9 — CFloat32

• 10 — CFloat64

Default: 0

Outputs

Output layer: mandatory to choose an existing raster layer if the (*) option is selected [raster]

<put output description here>

Console usage

processing .

runalg( ’gdalogr:rasterize’ , input , field, writeover, dimensions, width, height, rtype, output)

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See also

RGB to PCT

Description

<put algortithm description here>

Parameters

Input layer

[raster] <put parameter description here>

Number of colors

[number] <put parameter description here>

Default: 2

Outputs

Output layer

[raster] <put output description here>

Console usage

processing .

runalg( ’gdalogr:rgbtopct’ , input , ncolors, output)

See also

Translate (convert format)

Description

<put algortithm description here>

Parameters

Input layer

[raster] <put parameter description here>

Set the size of the output file (In pixels or %)

[number] <put parameter description here>

Default: 100

Output size is a percentage of input size

[boolean] <put parameter description here>

Default: True

Nodata value, leave as none to take the nodata value from input

[string] <put parameter description here>

Default: none

Expand

[selection] <put parameter description here>

Options:

• 0 — none

• 1 — gray

• 2 — rgb

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• 3 — rgba

Default: 0

Output projection for output file [leave blank to use input projection]

[crs]

<put parameter description here>

Default: None

Subset based on georeferenced coordinates

[extent] <put parameter description here>

Default: 0,1,0,1

Copy all subdatasets of this file to individual output files

[boolean] <put parameter description here>

Default: False

Additional creation parameters

[string] Optional.

<put parameter description here>

Default: (not set)

Output raster type

[selection] <put parameter description here>

Options:

• 0 — Byte

• 1 — Int16

• 2 — UInt16

• 3 — UInt32

• 4 — Int32

• 5 — Float32

• 6 — Float64

• 7 — CInt16

• 8 — CInt32

• 9 — CFloat32

• 10 — CFloat64

Default: 5

Outputs

Output layer

[raster] <put output description here>

Console usage

processing .

runalg( ’gdalogr:translate’ , input , outsize, outsize_perc, no_data, expand, srs, projwin, sds, extra, rtype, output)

.

See also

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18.1.3 GDAL extraction

Clip raster by extent

Description

<put algortithm description here>

Parameters

Input layer

[raster] <put parameter description here>

Nodata value, leave as none to take the nodata value from input

[string] <put parameter description here>

Default: none

Clipping extent

[extent] <put parameter description here>

Default: 0,1,0,1

Additional creation parameters

[string] Optional.

<put parameter description here>

Default: (not set)

Outputs

Output layer

[raster] <put output description here>

Console usage

processing .

runalg( ’gdalogr:cliprasterbyextent’ , input , no_data, projwin, extra, output)

See also

Clip raster by mask layer

Description

<put algortithm description here>

Parameters

Input layer

[raster] <put parameter description here>

Mask layer

[vector: polygon] <put parameter description here>

Nodata value, leave as none to take the nodata value from input

[string] <put parameter description here>

Default: none

Create and output alpha band

[boolean] <put parameter description here>

Default: False

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Keep resolution of output raster

[boolean] <put parameter description here>

Default: False

Additional creation parameters

[string] Optional.

<put parameter description here>

Default: (not set)

Outputs

Output layer

[raster] <put output description here>

Console usage

processing .

runalg( ’gdalogr:cliprasterbymasklayer’ , input , mask, no_data, alpha_band, keep_resolution, extra, output)

See also

Contour

Description

<put algortithm description here>

Parameters

Input layer

[raster] <put parameter description here>

Interval between contour lines

[number] <put parameter description here>

Default: 10.0

Attribute name (if not set, no elevation attribute is attached)

[string]

Optional.

<put parameter description here>

Default: ELEV

Additional creation parameters

[string] Optional.

<put parameter description here>

Default: (not set)

Outputs

Output file for contour lines (vector)

[vector] <put output description here>

Console usage

processing .

runalg( ’gdalogr:contour’ , input_raster, interval, field_name, extra, output_vector)

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.

See also

18.1.4 GDAL miscellaneous

Build Virtual Raster

Description

<put algortithm description here>

Parameters

Input layers

[multipleinput: rasters] <put parameter description here>

Resolution

[selection] <put parameter description here>

Options:

• 0 — average

• 1 — highest

• 2 — lowest

Default: 0

Layer stack

[boolean] <put parameter description here>

Default: True

Allow projection difference

[boolean] <put parameter description here>

Default: False

Outputs

Output layer

[raster] <put output description here>

Console usage

processing .

runalg( ’gdalogr:buildvirtualraster’ , input , resolution, separate, proj_difference, output)

See also

Merge

Description

<put algortithm description here>

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Parameters

Input layers

[multipleinput: rasters] <put parameter description here>

Grab pseudocolor table from first layer

[boolean] <put parameter description here>

Default: False

Layer stack

[boolean] <put parameter description here>

Default: False

Output raster type

[selection] <put parameter description here>

Options:

• 0 — Byte

• 1 — Int16

• 2 — UInt16

• 3 — UInt32

• 4 — Int32

• 5 — Float32

• 6 — Float64

• 7 — CInt16

• 8 — CInt32

• 9 — CFloat32

• 10 — CFloat64

Default: 5

Outputs

Output layer

[raster] <put output description here>

Console usage

processing .

runalg( ’gdalogr:merge’ , input , pct, separate, rtype, output)

See also

Build overviews (pyramids)

Description

<put algortithm description here>

Parameters

Input layer

[raster] <put parameter description here>

Overview levels

[string] <put parameter description here>

Default: 2 4 8 16

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Remove all existing overviews

[boolean] <put parameter description here>

Default: False

Resampling method

[selection] <put parameter description here>

Options:

• 0 — nearest

• 1 — average

• 2 — gauss

• 3 — cubic

• 4 — average_mp

• 5 — average_magphase

• 6 — mode

Default: 0

Overview format

[selection] <put parameter description here>

Options:

• 0 — Internal (if possible)

• 1 — External (GTiff .ovr)

• 2 — External (ERDAS Imagine .aux)

Default: 0

Outputs

Output layer

[raster] <put output description here>

Console usage

processing .

runalg( ’gdalogr:overviews’ , input , levels, clean, resampling_method, format)

See also

Information

Description

<put algortithm description here>

Parameters

Input layer

[raster] <put parameter description here>

Suppress GCP info

[boolean] <put parameter description here>

Default: False

Suppress metadata info

[boolean] <put parameter description here>

Default: False

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Outputs

Layer information

[html] <put output description here>

Console usage

processing .

runalg( ’gdalorg:rasterinfo’ , input , nogcp, nometadata, output)

.

See also

18.1.5 GDAL projections

Extract projection

Description

<put algortithm description here>

Parameters

Input file

[raster] <put parameter description here>

Create also .prj file

[boolean] <put parameter description here>

Default: False

Outputs

Console usage

processing .

runalg( ’gdalogr:extractprojection’ , input , prj_file)

See also

Warp (reproject)

Description

<put algortithm description here>

Parameters

Input layer

[raster] <put parameter description here>

Source SRS (EPSG Code)

[crs] <put parameter description here>

Default: EPSG:4326

Destination SRS (EPSG Code)

[crs] <put parameter description here>

Default: EPSG:4326

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Output file resolution in target georeferenced units (leave 0 for no change)

[number]

<put parameter description here>

Default: 0.0

Resampling method

[selection] <put parameter description here>

Options:

• 0 — near

• 1 — bilinear

• 2 — cubic

• 3 — cubicspline

• 4 — lanczos

Default: 0

Additional creation parameters

[string] Optional.

<put parameter description here>

Default: (not set)

Output raster type

[selection] <put parameter description here>

Options:

• 0 — Byte

• 1 — Int16

• 2 — UInt16

• 3 — UInt32

• 4 — Int32

• 5 — Float32

• 6 — Float64

• 7 — CInt16

• 8 — CInt32

• 9 — CFloat32

• 10 — CFloat64

Default: 5

Outputs

Output layer

[raster] <put output description here>

Console usage

processing .

runalg( ’gdalogr:warpreproject’ , input , source_srs, dest_srs, tr, method, extra, rtype, output)

.

See also

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18.1.6 OGR conversion

Convert format

Description

<put algortithm description here>

Parameters

Input layer

[vector: any] <put parameter description here>

Destination Format

[selection] <put parameter description here>

Options:

• 0 — ESRI Shapefile

• 1 — GeoJSON

• 2 — GeoRSS

• 3 — SQLite

• 4 — GMT

• 5 — MapInfo File

• 6 — INTERLIS 1

• 7 — INTERLIS 2

• 8 — GML

• 9 — Geoconcept

• 10 — DXF

• 11 — DGN

• 12 — CSV

• 13 — BNA

• 14 — S57

• 15 — KML

• 16 — GPX

• 17 — PGDump

• 18 — GPSTrackMaker

• 19 — ODS

• 20 — XLSX

• 21 — PDF

Default: 0

Creation Options

[string] Optional.

<put parameter description here>

Default: (not set)

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Outputs

Output layer

[vector] <put output description here>

Console usage

processing .

runalg( ’gdalogr:convertformat’ , input_layer, format, options, output_layer)

.

See also

18.1.7 OGR geoprocessing

Clip vectors by extent

Description

<put algortithm description here>

Parameters

Input layer

[vector: any] <put parameter description here>

Clip extent

[extent] <put parameter description here>

Default: 0,1,0,1

Additional creation Options

[string] Optional.

<put parameter description here>

Default: (not set)

Outputs

Output layer

[vector] <put output description here>

Console usage

processing .

runalg( ’gdalogr:clipvectorsbyextent’ , input_layer, clip_extent, options, output_layer)

See also

Clip vectors by polygon

Description

<put algortithm description here>

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Parameters

Input layer

[vector: any] <put parameter description here>

Clip layer

[vector: polygon] <put parameter description here>

Additional creation Options

[string] Optional.

<put parameter description here>

Default: (not set)

Outputs

Output layer

[vector] <put output description here>

Console usage

processing .

runalg( ’gdalogr:clipvectorsbypolygon’ , input_layer, clip_layer, options, output_layer)

.

See also

18.1.8 OGR miscellaneous

Execute SQL

Description

<put algortithm description here>

Parameters

Input layer

[vector: any] <put parameter description here>

SQL

[string] <put parameter description here>

Default: (not set)

Outputs

SQL result

[vector] <put output description here>

Console usage

processing .

runalg( ’gdalogr:executesql’ , input , sql, output)

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See also

Import Vector into PostGIS database (available connections)

Description

<put algortithm description here>

Parameters

Database (connection name)

[selection] <put parameter description here>

Options:

• 0 — local

Default: 0

Input layer

[vector: any] <put parameter description here>

Output geometry type

[selection] <put parameter description here>

Options:

• 0 —

• 1 — NONE

• 2 — GEOMETRY

• 3 — POINT

• 4 — LINESTRING

• 5 — POLYGON

• 6 — GEOMETRYCOLLECTION

• 7 — MULTIPOINT

• 8 — MULTIPOLYGON

• 9 — MULTILINESTRING

Default: 5

Input CRS (EPSG Code)

[crs] <put parameter description here>

Default: EPSG:4326

Output CRS (EPSG Code)

[crs] <put parameter description here>

Default: EPSG:4326

Schema name

[string] Optional.

<put parameter description here>

Default: public

Table name, leave blank to use input name

[string] Optional.

<put parameter description here>

Default: (not set)

Primary Key

[string] Optional.

<put parameter description here>

Default: id

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Geometry column name

[string] Optional.

<put parameter description here>

Default: geom

Vector dimensions

[selection] <put parameter description here>

Options:

• 0 — 2

• 1 — 3

Default: 0

Distance tolerance for simplification

[string] Optional.

<put parameter description here>

Default: (not set)

Maximum distance between 2 nodes (densification)

[string] Optional.

<put parameter description here>

Default: (not set)

Select features by extent (defined in input layer CRS)

[extent] <put parameter description here>

Default: 0,1,0,1

Clip the input layer using the above (rectangle) extent

[boolean] <put parameter description here>

Default: False

Select features using a SQL "WHERE"statement (Ex: column="value")

[string]

Optional.

<put parameter description here>

Default: (not set)

Group "n"features per transaction (Default: 20000)

[string] Optional.

<put parameter description here>

Default: (not set)

Overwrite existing table?

[boolean] <put parameter description here>

Default: True

Append to existing table?

[boolean] <put parameter description here>

Default: False

Append and add new fields to existing table?

[boolean] <put parameter description here>

Default: False

Do not launder columns/table name/s?

[boolean] <put parameter description here>

Default: False

Do not create Spatial Index?

[boolean] <put parameter description here>

Default: False

Continue after a failure, skipping the failed feature

[boolean] <put parameter description here>

Default: False

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Additional creation options

[string] Optional.

<put parameter description here>

Default: (not set)

Outputs

Console usage

processing .

runalg( ’gdalogr:importvectorintopostgisdatabaseavailableconnections’ , database, input_layer, gtype, s_srs, t_srs, schema, table, pk, geocolumn, dim, simplify, segmentize, spat, clip, where, gt, overwrite, append, addfields, launder, index, skipfailures, options)

See also

Import Vector into PostGIS database (new connection)

Description

<put algortithm description here>

Parameters

Input layer

[vector: any] <put parameter description here>

Output geometry type

[selection] <put parameter description here>

Options:

• 0 —

• 1 — NONE

• 2 — GEOMETRY

• 3 — POINT

• 4 — LINESTRING

• 5 — POLYGON

• 6 — GEOMETRYCOLLECTION

• 7 — MULTIPOINT

• 8 — MULTIPOLYGON

• 9 — MULTILINESTRING

Default: 5

Input CRS (EPSG Code)

[crs] <put parameter description here>

Default: EPSG:4326

Output CRS (EPSG Code)

[crs] <put parameter description here>

Default: EPSG:4326

Host

[string] <put parameter description here>

Default: localhost

Port

[string] <put parameter description here>

Default: 5432

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Username

[string] <put parameter description here>

Default: (not set)

Database Name

[string] <put parameter description here>

Default: (not set)

Password

[string] <put parameter description here>

Default: (not set)

Schema name

[string] Optional.

<put parameter description here>

Default: public

Table name, leave blank to use input name

[string] Optional.

<put parameter description here>

Default: (not set)

Primary Key

[string] Optional.

<put parameter description here>

Default: id

Geometry column name

[string] Optional.

<put parameter description here>

Default: geom

Vector dimensions

[selection] <put parameter description here>

Options:

• 0 — 2

• 1 — 3

Default: 0

Distance tolerance for simplification

[string] Optional.

<put parameter description here>

Default: (not set)

Maximum distance between 2 nodes (densification)

[string] Optional.

<put parameter description here>

Default: (not set)

Select features by extent (defined in input layer CRS)

[extent] <put parameter description here>

Default: 0,1,0,1

Clip the input layer using the above (rectangle) extent

[boolean] <put parameter description here>

Default: False

Select features using a SQL "WHERE"statement (Ex: column="value")

[string]

Optional.

<put parameter description here>

Default: (not set)

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Group "n"features per transaction (Default: 20000)

[string] Optional.

<put parameter description here>

Default: (not set)

Overwrite existing table?

[boolean] <put parameter description here>

Default: True

Append to existing table?

[boolean] <put parameter description here>

Default: False

Append and add new fields to existing table?

[boolean] <put parameter description here>

Default: False

Do not launder columns/table name/s?

[boolean] <put parameter description here>

Default: False

Do not create Spatial Index?

[boolean] <put parameter description here>

Default: False

Continue after a failure, skipping the failed feature

[boolean] <put parameter description here>

Default: False

Additional creation options

[string] Optional.

<put parameter description here>

Default: (not set)

Outputs

Console usage

processing .

runalg( ’gdalogr:importvectorintopostgisdatabasenewconnection’ , input_layer, gtype, s_srs, t_srs, host, port, user, dbname, password, schema, table, pk, geocolumn, dim, simplify, segmentize, spat, clip, where, gt, overwrite, append, addfields, launder, index, skipfailures, options)

See also

Information

Description

<put algortithm description here>

Parameters

Input layer

[vector: any] <put parameter description here>

Outputs

Layer information

[html] <put output description here>

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processing .

runalg( ’gdalogr:information’ , input , output)

.

See also

18.2 LAStools

LAStools is a collection of highly efficient, multicore command line tools for LiDAR data processing.

18.2.1 las2las_filter

Description

<put algortithm description here>

Parameters verbose

[boolean] <put parameter description here>

Default: False

input LAS/LAZ file

[file] Optional.

<put parameter description here>

filter (by return, classification, flags)

[selection] <put parameter description here>

Options:

• 0 — —

• 1 — keep_last

• 2 — keep_first

• 3 — keep_middle

• 4 — keep_single

• 5 — drop_single

• 6 — keep_double

• 7 — keep_class 2

• 8 — keep_class 2 8

• 9 — keep_class 8

• 10 — keep_class 6

• 11 — keep_class 9

• 12 — keep_class 3 4 5

• 13 — keep_class 2 6

• 14 — drop_class 7

• 15 — drop_withheld

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Default: 0

second filter (by return, classification, flags)

[selection] <put parameter description here>

Options:

• 0 — —

• 1 — keep_last

• 2 — keep_first

• 3 — keep_middle

• 4 — keep_single

• 5 — drop_single

• 6 — keep_double

• 7 — keep_class 2

• 8 — keep_class 2 8

• 9 — keep_class 8

• 10 — keep_class 6

• 11 — keep_class 9

• 12 — keep_class 3 4 5

• 13 — keep_class 2 6

• 14 — drop_class 7

• 15 — drop_withheld

Default: 0

filter (by coordinate, intensity, GPS time, ...)

[selection] <put parameter description here>

Options:

• 0 — —

• 1 — clip_x_above

• 2 — clip_x_below

• 3 — clip_y_above

• 4 — clip_y_below

• 5 — clip_z_above

• 6 — clip_z_below

• 7 — drop_intensity_above

• 8 — drop_intensity_below

• 9 — drop_gps_time_above

• 10 — drop_gps_time_below

• 11 — drop_scan_angle_above

• 12 — drop_scan_angle_below

• 13 — keep_point_source

• 14 — drop_point_source

• 15 — drop_point_source_above

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• 16 — drop_point_source_below

• 17 — keep_user_data

• 18 — drop_user_data

• 19 — drop_user_data_above

• 20 — drop_user_data_below

• 21 — keep_every_nth

• 22 — keep_random_fraction

• 23 — thin_with_grid

Default: 0

value for filter (by coordinate, intensity, GPS time, ...)

[string] <put parameter description here>

Default: (not set)

second filter (by coordinate, intensity, GPS time, ...)

[selection] <put parameter description here>

Options:

• 0 — —

• 1 — clip_x_above

• 2 — clip_x_below

• 3 — clip_y_above

• 4 — clip_y_below

• 5 — clip_z_above

• 6 — clip_z_below

• 7 — drop_intensity_above

• 8 — drop_intensity_below

• 9 — drop_gps_time_above

• 10 — drop_gps_time_below

• 11 — drop_scan_angle_above

• 12 — drop_scan_angle_below

• 13 — keep_point_source

• 14 — drop_point_source

• 15 — drop_point_source_above

• 16 — drop_point_source_below

• 17 — keep_user_data

• 18 — drop_user_data

• 19 — drop_user_data_above

• 20 — drop_user_data_below

• 21 — keep_every_nth

• 22 — keep_random_fraction

• 23 — thin_with_grid

Default: 0

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value for second filter (by coordinate, intensity, GPS time, ...)

[string] <put parameter description here>

Default: (not set)

Outputs output LAS/LAZ file

[file] <put output description here>

Console usage

processing .

runalg( ’lidartools:las2lasfilter’ , verbose, input_laslaz, filter_return_class_flags1, filter_return_class_flags2, filter_coords_intensity1, filter_coords_intensity1_arg, filter_coords_intensity2, filter_coords_intensity2_arg, output_laslaz)

See also

18.2.2 las2las_project

Description

<put algortithm description here>

Parameters verbose

[boolean] <put parameter description here>

Default: False

input LAS/LAZ file

[file] Optional.

<put parameter description here>

source projection

[selection] <put parameter description here>

Options:

• 0 — —

• 1 — utm

• 2 — sp83

• 3 — sp27

• 4 — longlat

• 5 — latlong

Default: 0

source utm zone

[selection] <put parameter description here>

Options:

• 0 — —

• 1 — 1 (north)

• 2 — 2 (north)

• 3 — 3 (north)

• 4 — 4 (north)

• 5 — 5 (north)

• 6 — 6 (north)

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• 7 — 7 (north)

• 8 — 8 (north)

• 9 — 9 (north)

• 10 — 10 (north)

• 11 — 11 (north)

• 12 — 12 (north)

• 13 — 13 (north)

• 14 — 14 (north)

• 15 — 15 (north)

• 16 — 16 (north)

• 17 — 17 (north)

• 18 — 18 (north)

• 19 — 19 (north)

• 20 — 20 (north)

• 21 — 21 (north)

• 22 — 22 (north)

• 23 — 23 (north)

• 24 — 24 (north)

• 25 — 25 (north)

• 26 — 26 (north)

• 27 — 27 (north)

• 28 — 28 (north)

• 29 — 29 (north)

• 30 — 30 (north)

• 31 — 31 (north)

• 32 — 32 (north)

• 33 — 33 (north)

• 34 — 34 (north)

• 35 — 35 (north)

• 36 — 36 (north)

• 37 — 37 (north)

• 38 — 38 (north)

• 39 — 39 (north)

• 40 — 40 (north)

• 41 — 41 (north)

• 42 — 42 (north)

• 43 — 43 (north)

• 44 — 44 (north)

• 45 — 45 (north)

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• 46 — 46 (north)

• 47 — 47 (north)

• 48 — 48 (north)

• 49 — 49 (north)

• 50 — 50 (north)

• 51 — 51 (north)

• 52 — 52 (north)

• 53 — 53 (north)

• 54 — 54 (north)

• 55 — 55 (north)

• 56 — 56 (north)

• 57 — 57 (north)

• 58 — 58 (north)

• 59 — 59 (north)

• 60 — 60 (north)

• 61 — 1 (south)

• 62 — 2 (south)

• 63 — 3 (south)

• 64 — 4 (south)

• 65 — 5 (south)

• 66 — 6 (south)

• 67 — 7 (south)

• 68 — 8 (south)

• 69 — 9 (south)

• 70 — 10 (south)

• 71 — 11 (south)

• 72 — 12 (south)

• 73 — 13 (south)

• 74 — 14 (south)

• 75 — 15 (south)

• 76 — 16 (south)

• 77 — 17 (south)

• 78 — 18 (south)

• 79 — 19 (south)

• 80 — 20 (south)

• 81 — 21 (south)

• 82 — 22 (south)

• 83 — 23 (south)

• 84 — 24 (south)

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• 85 — 25 (south)

• 86 — 26 (south)

• 87 — 27 (south)

• 88 — 28 (south)

• 89 — 29 (south)

• 90 — 30 (south)

• 91 — 31 (south)

• 92 — 32 (south)

• 93 — 33 (south)

• 94 — 34 (south)

• 95 — 35 (south)

• 96 — 36 (south)

• 97 — 37 (south)

• 98 — 38 (south)

• 99 — 39 (south)

• 100 — 40 (south)

• 101 — 41 (south)

• 102 — 42 (south)

• 103 — 43 (south)

• 104 — 44 (south)

• 105 — 45 (south)

• 106 — 46 (south)

• 107 — 47 (south)

• 108 — 48 (south)

• 109 — 49 (south)

• 110 — 50 (south)

• 111 — 51 (south)

• 112 — 52 (south)

• 113 — 53 (south)

• 114 — 54 (south)

• 115 — 55 (south)

• 116 — 56 (south)

• 117 — 57 (south)

• 118 — 58 (south)

• 119 — 59 (south)

• 120 — 60 (south)

Default: 0

source state plane code

[selection] <put parameter description here>

Options:

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• 0 — —

• 1 — AK_10

• 2 — AK_2

• 3 — AK_3

• 4 — AK_4

• 5 — AK_5

• 6 — AK_6

• 7 — AK_7

• 8 — AK_8

• 9 — AK_9

• 10 — AL_E

• 11 — AL_W

• 12 — AR_N

• 13 — AR_S

• 14 — AZ_C

• 15 — AZ_E

• 16 — AZ_W

• 17 — CA_I

• 18 — CA_II

• 19 — CA_III

• 20 — CA_IV

• 21 — CA_V

• 22 — CA_VI

• 23 — CA_VII

• 24 — CO_C

• 25 — CO_N

• 26 — CO_S

• 27 — CT

• 28 — DE

• 29 — FL_E

• 30 — FL_N

• 31 — FL_W

• 32 — GA_E

• 33 — GA_W

• 34 — HI_1

• 35 — HI_2

• 36 — HI_3

• 37 — HI_4

• 38 — HI_5

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• 39 — IA_N

• 40 — IA_S

• 41 — ID_C

• 42 — ID_E

• 43 — ID_W

• 44 — IL_E

• 45 — IL_W

• 46 — IN_E

• 47 — IN_W

• 48 — KS_N

• 49 — KS_S

• 50 — KY_N

• 51 — KY_S

• 52 — LA_N

• 53 — LA_S

• 54 — MA_I

• 55 — MA_M

• 56 — MD

• 57 — ME_E

• 58 — ME_W

• 59 — MI_C

• 60 — MI_N

• 61 — MI_S

• 62 — MN_C

• 63 — MN_N

• 64 — MN_S

• 65 — MO_C

• 66 — MO_E

• 67 — MO_W

• 68 — MS_E

• 69 — MS_W

• 70 — MT_C

• 71 — MT_N

• 72 — MT_S

• 73 — NC

• 74 — ND_N

• 75 — ND_S

• 76 — NE_N

• 77 — NE_S

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• 78 — NH

• 79 — NJ

• 80 — NM_C

• 81 — NM_E

• 82 — NM_W

• 83 — NV_C

• 84 — NV_E

• 85 — NV_W

• 86 — NY_C

• 87 — NY_E

• 88 — NY_LI

• 89 — NY_W

• 90 — OH_N

• 91 — OH_S

• 92 — OK_N

• 93 — OK_S

• 94 — OR_N

• 95 — OR_S

• 96 — PA_N

• 97 — PA_S

• 98 — PR

• 99 — RI

• 100 — SC_N

• 101 — SC_S

• 102 — SD_N

• 103 — SD_S

• 104 — St.Croix

• 105 — TN

• 106 — TX_C

• 107 — TX_N

• 108 — TX_NC

• 109 — TX_S

• 110 — TX_SC

• 111 — UT_C

• 112 — UT_N

• 113 — UT_S

• 114 — VA_N

• 115 — VA_S

• 116 — VT

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• 117 — WA_N

• 118 — WA_S

• 119 — WI_C

• 120 — WI_N

• 121 — WI_S

• 122 — WV_N

• 123 — WV_S

• 124 — WY_E

• 125 — WY_EC

• 126 — WY_W

• 127 — WY_WC

Default: 0

target projection

[selection] <put parameter description here>

Options:

• 0 — —

• 1 — utm

• 2 — sp83

• 3 — sp27

• 4 — longlat

• 5 — latlong

Default: 0

target utm zone

[selection] <put parameter description here>

Options:

• 0 — —

• 1 — 1 (north)

• 2 — 2 (north)

• 3 — 3 (north)

• 4 — 4 (north)

• 5 — 5 (north)

• 6 — 6 (north)

• 7 — 7 (north)

• 8 — 8 (north)

• 9 — 9 (north)

• 10 — 10 (north)

• 11 — 11 (north)

• 12 — 12 (north)

• 13 — 13 (north)

• 14 — 14 (north)

• 15 — 15 (north)

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• 16 — 16 (north)

• 17 — 17 (north)

• 18 — 18 (north)

• 19 — 19 (north)

• 20 — 20 (north)

• 21 — 21 (north)

• 22 — 22 (north)

• 23 — 23 (north)

• 24 — 24 (north)

• 25 — 25 (north)

• 26 — 26 (north)

• 27 — 27 (north)

• 28 — 28 (north)

• 29 — 29 (north)

• 30 — 30 (north)

• 31 — 31 (north)

• 32 — 32 (north)

• 33 — 33 (north)

• 34 — 34 (north)

• 35 — 35 (north)

• 36 — 36 (north)

• 37 — 37 (north)

• 38 — 38 (north)

• 39 — 39 (north)

• 40 — 40 (north)

• 41 — 41 (north)

• 42 — 42 (north)

• 43 — 43 (north)

• 44 — 44 (north)

• 45 — 45 (north)

• 46 — 46 (north)

• 47 — 47 (north)

• 48 — 48 (north)

• 49 — 49 (north)

• 50 — 50 (north)

• 51 — 51 (north)

• 52 — 52 (north)

• 53 — 53 (north)

• 54 — 54 (north)

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• 55 — 55 (north)

• 56 — 56 (north)

• 57 — 57 (north)

• 58 — 58 (north)

• 59 — 59 (north)

• 60 — 60 (north)

• 61 — 1 (south)

• 62 — 2 (south)

• 63 — 3 (south)

• 64 — 4 (south)

• 65 — 5 (south)

• 66 — 6 (south)

• 67 — 7 (south)

• 68 — 8 (south)

• 69 — 9 (south)

• 70 — 10 (south)

• 71 — 11 (south)

• 72 — 12 (south)

• 73 — 13 (south)

• 74 — 14 (south)

• 75 — 15 (south)

• 76 — 16 (south)

• 77 — 17 (south)

• 78 — 18 (south)

• 79 — 19 (south)

• 80 — 20 (south)

• 81 — 21 (south)

• 82 — 22 (south)

• 83 — 23 (south)

• 84 — 24 (south)

• 85 — 25 (south)

• 86 — 26 (south)

• 87 — 27 (south)

• 88 — 28 (south)

• 89 — 29 (south)

• 90 — 30 (south)

• 91 — 31 (south)

• 92 — 32 (south)

• 93 — 33 (south)

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• 94 — 34 (south)

• 95 — 35 (south)

• 96 — 36 (south)

• 97 — 37 (south)

• 98 — 38 (south)

• 99 — 39 (south)

• 100 — 40 (south)

• 101 — 41 (south)

• 102 — 42 (south)

• 103 — 43 (south)

• 104 — 44 (south)

• 105 — 45 (south)

• 106 — 46 (south)

• 107 — 47 (south)

• 108 — 48 (south)

• 109 — 49 (south)

• 110 — 50 (south)

• 111 — 51 (south)

• 112 — 52 (south)

• 113 — 53 (south)

• 114 — 54 (south)

• 115 — 55 (south)

• 116 — 56 (south)

• 117 — 57 (south)

• 118 — 58 (south)

• 119 — 59 (south)

• 120 — 60 (south)

Default: 0

target state plane code

[selection] <put parameter description here>

Options:

• 0 — —

• 1 — AK_10

• 2 — AK_2

• 3 — AK_3

• 4 — AK_4

• 5 — AK_5

• 6 — AK_6

• 7 — AK_7

• 8 — AK_8

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• 9 — AK_9

• 10 — AL_E

• 11 — AL_W

• 12 — AR_N

• 13 — AR_S

• 14 — AZ_C

• 15 — AZ_E

• 16 — AZ_W

• 17 — CA_I

• 18 — CA_II

• 19 — CA_III

• 20 — CA_IV

• 21 — CA_V

• 22 — CA_VI

• 23 — CA_VII

• 24 — CO_C

• 25 — CO_N

• 26 — CO_S

• 27 — CT

• 28 — DE

• 29 — FL_E

• 30 — FL_N

• 31 — FL_W

• 32 — GA_E

• 33 — GA_W

• 34 — HI_1

• 35 — HI_2

• 36 — HI_3

• 37 — HI_4

• 38 — HI_5

• 39 — IA_N

• 40 — IA_S

• 41 — ID_C

• 42 — ID_E

• 43 — ID_W

• 44 — IL_E

• 45 — IL_W

• 46 — IN_E

• 47 — IN_W

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• 48 — KS_N

• 49 — KS_S

• 50 — KY_N

• 51 — KY_S

• 52 — LA_N

• 53 — LA_S

• 54 — MA_I

• 55 — MA_M

• 56 — MD

• 57 — ME_E

• 58 — ME_W

• 59 — MI_C

• 60 — MI_N

• 61 — MI_S

• 62 — MN_C

• 63 — MN_N

• 64 — MN_S

• 65 — MO_C

• 66 — MO_E

• 67 — MO_W

• 68 — MS_E

• 69 — MS_W

• 70 — MT_C

• 71 — MT_N

• 72 — MT_S

• 73 — NC

• 74 — ND_N

• 75 — ND_S

• 76 — NE_N

• 77 — NE_S

• 78 — NH

• 79 — NJ

• 80 — NM_C

• 81 — NM_E

• 82 — NM_W

• 83 — NV_C

• 84 — NV_E

• 85 — NV_W

• 86 — NY_C

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• 87 — NY_E

• 88 — NY_LI

• 89 — NY_W

• 90 — OH_N

• 91 — OH_S

• 92 — OK_N

• 93 — OK_S

• 94 — OR_N

• 95 — OR_S

• 96 — PA_N

• 97 — PA_S

• 98 — PR

• 99 — RI

• 100 — SC_N

• 101 — SC_S

• 102 — SD_N

• 103 — SD_S

• 104 — St.Croix

• 105 — TN

• 106 — TX_C

• 107 — TX_N

• 108 — TX_NC

• 109 — TX_S

• 110 — TX_SC

• 111 — UT_C

• 112 — UT_N

• 113 — UT_S

• 114 — VA_N

• 115 — VA_S

• 116 — VT

• 117 — WA_N

• 118 — WA_S

• 119 — WI_C

• 120 — WI_N

• 121 — WI_S

• 122 — WV_N

• 123 — WV_S

• 124 — WY_E

• 125 — WY_EC

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• 126 — WY_W

• 127 — WY_WC

Default: 0

Outputs output LAS/LAZ file

[file] <put output description here>

Console usage

processing .

runalg( ’lidartools:las2lasproject’ , verbose, input_laslaz, source_projection, source_utm, source_sp, target_projection, target_utm, target_sp, output_laslaz)

See also

18.2.3 las2las_transform

Description

<put algortithm description here>

Parameters verbose

[boolean] <put parameter description here>

Default: False

input LAS/LAZ file

[file] Optional.

<put parameter description here>

transform (coordinates)

[selection] <put parameter description here>

Options:

• 0 — —

• 1 — translate_x

• 2 — translate_y

• 3 — translate_z

• 4 — scale_x

• 5 — scale_y

• 6 — scale_z

• 7 — clamp_z_above

• 8 — clamp_z_below

Default: 0

value for transform (coordinates)

[string] <put parameter description here>

Default: (not set)

second transform (coordinates)

[selection] <put parameter description here>

Options:

• 0 — —

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• 1 — translate_x

• 2 — translate_y

• 3 — translate_z

• 4 — scale_x

• 5 — scale_y

• 6 — scale_z

• 7 — clamp_z_above

• 8 — clamp_z_below

Default: 0

value for second transform (coordinates)

[string] <put parameter description here>

Default: (not set)

transform (intensities, scan angles, GPS times, ...)

[selection] <put parameter description here>

Options:

• 0 — —

• 1 — scale_intensity

• 2 — translate_intensity

• 3 — clamp_intensity_above

• 4 — clamp_intensity_below

• 5 — scale_scan_angle

• 6 — translate_scan_angle

• 7 — translate_gps_time

• 8 — set_classification

• 9 — set_user_data

• 10 — set_point_source

• 11 — scale_rgb_up

• 12 — scale_rgb_down

• 13 — repair_zero_returns

Default: 0

value for transform (intensities, scan angles, GPS times, ...)

[string] <put parameter description here>

Default: (not set)

second transform (intensities, scan angles, GPS times, ...)

[selection] <put parameter description here>

Options:

• 0 — —

• 1 — scale_intensity

• 2 — translate_intensity

• 3 — clamp_intensity_above

• 4 — clamp_intensity_below

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• 5 — scale_scan_angle

• 6 — translate_scan_angle

• 7 — translate_gps_time

• 8 — set_classification

• 9 — set_user_data

• 10 — set_point_source

• 11 — scale_rgb_up

• 12 — scale_rgb_down

• 13 — repair_zero_returns

Default: 0

value for second transform (intensities, scan angles, GPS times, ...)

[string]

<put parameter description here>

Default: (not set)

operations (first 7 need an argument)

[selection] <put parameter description here>

Options:

• 0 — —

• 1 — set_point_type

• 2 — set_point_size

• 3 — set_version_minor

• 4 — set_version_major

• 5 — start_at_point

• 6 — stop_at_point

• 7 — remove_vlr

• 8 — auto_reoffset

• 9 — week_to_adjusted

• 10 — adjusted_to_week

• 11 — scale_rgb_up

• 12 — scale_rgb_down

• 13 — remove_all_vlrs

• 14 — remove_extra

• 15 — clip_to_bounding_box

Default: 0

argument for operation

[string] <put parameter description here>

Default: (not set)

Outputs output LAS/LAZ file

[file] <put output description here>

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Console usage

processing .

runalg( ’lidartools:las2lastransform’ , verbose, input_laslaz, transform_coordinate1, transform_coordinate1_arg, transform_coordinate2, transform_coordinate2_arg, transform_other1, transform_other1_arg, transform_other2, transform_other2_arg, operation, operationarg, output_laslaz)

See also

18.2.4 las2txt

Description

<put algortithm description here>

Parameters verbose

[boolean] <put parameter description here>

Default: False

input LAS/LAZ file

[file] Optional.

<put parameter description here>

parse_string

[string] <put parameter description here>

Default: xyz

Outputs

Output ASCII file

[file] <put output description here>

Console usage

processing .

runalg( ’lidartools:las2txt’ , verbose, input_laslaz, parse_string, output)

See also

18.2.5 lasindex

Description

<put algortithm description here>

Parameters verbose

[boolean] <put parameter description here>

Default: False

input LAS/LAZ file

[file] Optional.

<put parameter description here>

is mobile or terrestrial LiDAR (not airborne)

[boolean] <put parameter description here>

Default: False

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Outputs

Console usage

processing .

runalg( ’lidartools:lasindex’ , verbose, input_laslaz, mobile_or_terrestrial)

See also

18.2.6 lasinfo

Description

<put algortithm description here>

Parameters verbose

[boolean] <put parameter description here>

Default: False

input LAS/LAZ file

[file] Optional.

<put parameter description here>

Outputs

Output ASCII file

[file] <put output description here>

Console usage

processing .

runalg( ’lidartools:lasinfo’ , verbose, input_laslaz, output)

See also

18.2.7 lasmerge

Description

<put algortithm description here>

Parameters verbose

[boolean] <put parameter description here>

Default: False

files are flightlines

[boolean] <put parameter description here>

Default: True

input LAS/LAZ file

[file] Optional.

<put parameter description here>

2nd file

[file] Optional.

<put parameter description here>

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3rd file

[file] Optional.

<put parameter description here>

4th file

[file] Optional.

<put parameter description here>

5th file

[file] Optional.

<put parameter description here>

6th file

[file] Optional.

<put parameter description here>

7th file

[file] Optional.

<put parameter description here>

Outputs output LAS/LAZ file

[file] <put output description here>

Console usage

processing .

runalg( ’lidartools:lasmerge’ , verbose, files_are_flightlines, input_laslaz, file2, file3, file4, file5, file6, file7, output_laslaz)

See also

18.2.8 lasprecision

Description

<put algortithm description here>

Parameters verbose

[boolean] <put parameter description here>

Default: False

input LAS/LAZ file

[file] Optional.

<put parameter description here>

Outputs

Output ASCII file

[file] <put output description here>

Console usage

processing .

runalg( ’lidartools:lasprecision’ , verbose, input_laslaz, output)

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See also

18.2.9 lasquery

Description

<put algortithm description here>

Parameters verbose

[boolean] <put parameter description here>

Default: False

area of interest

[extent] <put parameter description here>

Default: 0,1,0,1

Outputs

Console usage

processing .

runalg( ’lidartools:lasquery’ , verbose, aoi)

See also

18.2.10 lasvalidate

Description

<put algortithm description here>

Parameters verbose

[boolean] <put parameter description here>

Default: False

input LAS/LAZ file

[file] Optional.

<put parameter description here>

Outputs

Output XML file

[file] <put output description here>

Console usage

processing .

runalg( ’lidartools:lasvalidate’ , verbose, input_laslaz, output)

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See also

18.2.11 laszip

Description

<put algortithm description here>

Parameters verbose

[boolean] <put parameter description here>

Default: False

input LAS/LAZ file

[file] Optional.

<put parameter description here>

only report size

[boolean] <put parameter description here>

Default: False

Outputs output LAS/LAZ file

[file] <put output description here>

Console usage

processing .

runalg( ’lidartools:laszip’ , verbose, input_laslaz, report_size, output_laslaz)

See also

18.2.12 txt2las

Description

<put algortithm description here>

Parameters verbose

[boolean] <put parameter description here>

Default: False

Input ASCII file

[file] Optional.

<put parameter description here>

parse lines as

[string] <put parameter description here>

Default: xyz

skip the first n lines

[number] <put parameter description here>

Default: 0

resolution of x and y coordinate

[number] <put parameter description here>

Default: 0.01

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resolution of z coordinate

[number] <put parameter description here>

Default: 0.01

Outputs output LAS/LAZ file

[file] <put output description here>

Console usage

processing .

runalg( ’lidartools:txt2las’ , verbose, input , parse_string, skip, scale_factor_xy, scale_factor_z, output_laslaz)

.

See also

18.3 Modeler Tools

18.3.1 Calculator

Description

<put algortithm description here>

Parameters

Formula

[string] <put parameter description here>

Default: (not set)

dummy

[number] <put parameter description here>

Default: 0.0

dummy

[number] <put parameter description here>

Default: 0.0

dummy

[number] <put parameter description here>

Default: 0.0

dummy

[number] <put parameter description here>

Default: 0.0

dummy

[number] <put parameter description here>

Default: 0.0

dummy

[number] <put parameter description here>

Default: 0.0

dummy

[number] <put parameter description here>

Default: 0.0

dummy

[number] <put parameter description here>

Default: 0.0

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dummy

[number] <put parameter description here>

Default: 0.0

dummy

[number] <put parameter description here>

Default: 0.0

Outputs

Result

[number] <put output description here>

Console usage

processing .

runalg( ’modelertools:calculator’ , formula, number0, number1, number2, number3, number4, number5, number6, number7, number8, number9)

See also

18.3.2 Raster layer bounds

Description

<put algortithm description here>

Parameters

Layer

[raster] <put parameter description here>

Outputs min X

[number] <put output description here>

max X

[number] <put output description here>

min Y

[number] <put output description here>

max Y

[number] <put output description here>

Extent

[extent] <put output description here>

Console usage

processing .

runalg( ’modelertools:rasterlayerbounds’ , layer)

See also

18.3.3 Vector layer bounds

Description

<put algortithm description here>

Parameters

Layer

[vector: any] <put parameter description here>

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Outputs min X

[number] <put output description here>

max X

[number] <put output description here>

min Y

[number] <put output description here>

max Y

[number] <put output description here>

Extent

[extent] <put output description here>

Console usage

processing .

runalg( ’modelertools:vectorlayerbounds’ , layer)

.

See also

18.4 OrfeoToolbox algorithm provider

.

Orfeo ToolBox (OTB) is an open source library of image processing algorithms. OTB is based on the medical image processing library ITK and offers particular functionalities for remote sensing image processing in general and for high spatial resolution images in particular. Targeted algorithms for high resolution optical images

(Pleiades, SPOT, QuickBird, WorldView, Landsat, Ikonos), hyperspectral sensors (Hyperion) or SAR (TerraSarX,

ERS, Palsar) are available.

Muista: Please remember that Processing contains only the interface description, so you need to install OTB by yourself and configure Processing properly.

18.4.1 Calibration

Optical calibration

Description

<put algortithm description here>

Parameters

Input

[raster] <put parameter description here>

Available RAM (Mb)

[number] <put parameter description here>

Default: 128

Calibration Level

[selection] <put parameter description here>

Options:

• 0 — toa

Default: 0

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Convert to milli reflectance

[boolean] <put parameter description here>

Default: True

Clamp of reflectivity values between [0, 100]

[boolean] <put parameter description here>

Default: True

Relative Spectral Response File

[file] Optional.

<put parameter description here>

Outputs

Output

[raster] <put output description here>

Console usage

processing.runalg(’otb:opticalcalibration’, -in, -ram, -level, -milli, -clamp, -rsr, -out)

.

See also

18.4.2 Feature extrcation

BinaryMorphologicalOperation (closing)

Description

<put algortithm description here>

Parameters

Input Image

[raster] <put parameter description here>

Selected Channel

[number] <put parameter description here>

Default: 1

Available RAM (Mb)

[number] <put parameter description here>

Default: 128

Structuring Element Type

[selection] <put parameter description here>

Options:

• 0 — ball

Default: 0

The Structuring Element Radius

[number] <put parameter description here>

Default: 5

Morphological Operation

[selection] <put parameter description here>

Options:

• 0 — closing

Default: 0

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Outputs

Feature Output Image

[raster] <put output description here>

Console usage

processing.runalg(’otb:binarymorphologicaloperationclosing’, -in, -channel, -ram, -structype, -structype.ball.xradius, -filter, -out)

See also

BinaryMorphologicalOperation (dilate)

Description

<put algortithm description here>

Parameters

Input Image

[raster] <put parameter description here>

Selected Channel

[number] <put parameter description here>

Default: 1

Available RAM (Mb)

[number] <put parameter description here>

Default: 128

Structuring Element Type

[selection] <put parameter description here>

Options:

• 0 — ball

Default: 0

The Structuring Element Radius

[number] <put parameter description here>

Default: 5

Morphological Operation

[selection] <put parameter description here>

Options:

• 0 — dilate

Default: 0

Foreground Value

[number] <put parameter description here>

Default: 1

Background Value

[number] <put parameter description here>

Default: 0

Outputs

Feature Output Image

[raster] <put output description here>

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Console usage

processing.runalg(’otb:binarymorphologicaloperationdilate’, -in, -channel, -ram, -structype, -structype.ball.xradius, -filter, -filter.dilate.foreval, -filter.dilate.backval, -out)

See also

BinaryMorphologicalOperation (erode)

Description

<put algortithm description here>

Parameters

Input Image

[raster] <put parameter description here>

Selected Channel

[number] <put parameter description here>

Default: 1

Available RAM (Mb)

[number] <put parameter description here>

Default: 128

Structuring Element Type

[selection] <put parameter description here>

Options:

• 0 — ball

Default: 0

The Structuring Element Radius

[number] <put parameter description here>

Default: 5

Morphological Operation

[selection] <put parameter description here>

Options:

• 0 — erode

Default: 0

Outputs

Feature Output Image

[raster] <put output description here>

Console usage

processing.runalg(’otb:binarymorphologicaloperationerode’, -in, -channel, -ram, -structype, -structype.ball.xradius, -filter, -out)

See also

BinaryMorphologicalOperation (opening)

Description

<put algortithm description here>

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Parameters

Input Image

[raster] <put parameter description here>

Selected Channel

[number] <put parameter description here>

Default: 1

Available RAM (Mb)

[number] <put parameter description here>

Default: 128

Structuring Element Type

[selection] <put parameter description here>

Options:

• 0 — ball

Default: 0

The Structuring Element Radius

[number] <put parameter description here>

Default: 5

Morphological Operation

[selection] <put parameter description here>

Options:

• 0 — opening

Default: 0

Outputs

Feature Output Image

[raster] <put output description here>

Console usage

processing.runalg(’otb:binarymorphologicaloperationopening’, -in, -channel, -ram, -structype, -structype.ball.xradius, -filter, -out)

See also

EdgeExtraction (gradient)

Description

<put algortithm description here>

Parameters

Input Image

[raster] <put parameter description here>

Selected Channel

[number] <put parameter description here>

Default: 1

Available RAM (Mb)

[number] <put parameter description here>

Default: 128

Edge feature

[selection] <put parameter description here>

Options:

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• 0 — gradient

Default: 0

Outputs

Feature Output Image

[raster] <put output description here>

Console usage

processing.runalg(’otb:edgeextractiongradient’, -in, -channel, -ram, -filter, -out)

See also

EdgeExtraction (sobel)

Description

<put algortithm description here>

Parameters

Input Image

[raster] <put parameter description here>

Selected Channel

[number] <put parameter description here>

Default: 1

Available RAM (Mb)

[number] <put parameter description here>

Default: 128

Edge feature

[selection] <put parameter description here>

Options:

• 0 — sobel

Default: 0

Outputs

Feature Output Image

[raster] <put output description here>

Console usage

processing.runalg(’otb:edgeextractionsobel’, -in, -channel, -ram, -filter, -out)

See also

EdgeExtraction (touzi)

Description

<put algortithm description here>

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Parameters

Input Image

[raster] <put parameter description here>

Selected Channel

[number] <put parameter description here>

Default: 1

Available RAM (Mb)

[number] <put parameter description here>

Default: 128

Edge feature

[selection] <put parameter description here>

Options:

• 0 — touzi

Default: 0

The Radius

[number] <put parameter description here>

Default: 1

Outputs

Feature Output Image

[raster] <put output description here>

Console usage

processing.runalg(’otb:edgeextractiontouzi’, -in, -channel, -ram, -filter, -filter.touzi.xradius, -out)

See also

GrayScaleMorphologicalOperation (closing)

Description

<put algortithm description here>

Parameters

Input Image

[raster] <put parameter description here>

Selected Channel

[number] <put parameter description here>

Default: 1

Available RAM (Mb)

[number] <put parameter description here>

Default: 128

Structuring Element Type

[selection] <put parameter description here>

Options:

• 0 — ball

Default: 0

The Structuring Element Radius

[number] <put parameter description here>

Default: 5

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Morphological Operation

[selection] <put parameter description here>

Options:

• 0 — closing

Default: 0

Outputs

Feature Output Image

[raster] <put output description here>

Console usage

processing.runalg(’otb:grayscalemorphologicaloperationclosing’, -in, -channel, -ram, -structype, -structype.ball.xradius, -filter, -out)

See also

GrayScaleMorphologicalOperation (dilate)

Description

<put algortithm description here>

Parameters

Input Image

[raster] <put parameter description here>

Selected Channel

[number] <put parameter description here>

Default: 1

Available RAM (Mb)

[number] <put parameter description here>

Default: 128

Structuring Element Type

[selection] <put parameter description here>

Options:

• 0 — ball

Default: 0

The Structuring Element Radius

[number] <put parameter description here>

Default: 5

Morphological Operation

[selection] <put parameter description here>

Options:

• 0 — dilate

Default: 0

Outputs

Feature Output Image

[raster] <put output description here>

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Console usage

processing.runalg(’otb:grayscalemorphologicaloperationdilate’, -in, -channel, -ram, -structype, -structype.ball.xradius, -filter, -out)

See also

GrayScaleMorphologicalOperation (erode)

Description

<put algortithm description here>

Parameters

Input Image

[raster] <put parameter description here>

Selected Channel

[number] <put parameter description here>

Default: 1

Available RAM (Mb)

[number] <put parameter description here>

Default: 128

Structuring Element Type

[selection] <put parameter description here>

Options:

• 0 — ball

Default: 0

The Structuring Element Radius

[number] <put parameter description here>

Default: 5

Morphological Operation

[selection] <put parameter description here>

Options:

• 0 — erode

Default: 0

Outputs

Feature Output Image

[raster] <put output description here>

Console usage

processing.runalg(’otb:grayscalemorphologicaloperationerode’, -in, -channel, -ram, -structype, -structype.ball.xradius, -filter, -out)

See also

GrayScaleMorphologicalOperation (opening)

Description

<put algortithm description here>

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Parameters

Input Image

[raster] <put parameter description here>

Selected Channel

[number] <put parameter description here>

Default: 1

Available RAM (Mb)

[number] <put parameter description here>

Default: 128

Structuring Element Type

[selection] <put parameter description here>

Options:

• 0 — ball

Default: 0

The Structuring Element Radius

[number] <put parameter description here>

Default: 5

Morphological Operation

[selection] <put parameter description here>

Options:

• 0 — opening

Default: 0

Outputs

Feature Output Image

[raster] <put output description here>

Console usage

processing.runalg(’otb:grayscalemorphologicaloperationopening’, -in, -channel, -ram, -structype, -structype.ball.xradius, -filter, -out)

See also

Haralick Texture Extraction

Description

<put algortithm description here>

Parameters

Input Image

[raster] <put parameter description here>

Selected Channel

[number] <put parameter description here>

Default: 1

Available RAM (Mb)

[number] <put parameter description here>

Default: 128

X Radius

[number] <put parameter description here>

Default: 2

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Y Radius

[number] <put parameter description here>

Default: 2

X Offset

[number] <put parameter description here>

Default: 1

Y Offset

[number] <put parameter description here>

Default: 1

Image Minimum

[number] <put parameter description here>

Default: 0

Image Maximum

[number] <put parameter description here>

Default: 255

Histogram number of bin

[number] <put parameter description here>

Default: 8

Texture Set Selection

[selection] <put parameter description here>

Options:

• 0 — simple

• 1 — advanced

• 2 — higher

Default: 0

Outputs

Output Image

[raster] <put output description here>

Console usage

processing.runalg(’otb:haralicktextureextraction’, -in, -channel, -ram, -parameters.xrad, -parameters.yrad, -parameters.xoff, -parameters.yoff, -parameters.min, -parameters.max, -parameters.nbbin, -texture, -out)

See also

Line segment detection

Description

<put algortithm description here>

Parameters

Input Image

[raster] <put parameter description here>

No rescaling in [0, 255]

[boolean] <put parameter description here>

Default: True

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Outputs

Output Detected lines

[vector] <put output description here>

Console usage

processing.runalg(’otb:linesegmentdetection’, -in, -norescale, -out)

See also

Local Statistic Extraction

Description

<put algortithm description here>

Parameters

Input Image

[raster] <put parameter description here>

Selected Channel

[number] <put parameter description here>

Default: 1

Available RAM (Mb)

[number] <put parameter description here>

Default: 128

Neighborhood radius

[number] <put parameter description here>

Default: 3

Outputs

Feature Output Image

[raster] <put output description here>

Console usage

processing.runalg(’otb:localstatisticextraction’, -in, -channel, -ram, -radius, -out)

See also

Multivariate alteration detector

Description

<put algortithm description here>

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Parameters

Input Image 1

[raster] <put parameter description here>

Input Image 2

[raster] <put parameter description here>

Available RAM (Mb)

[number] <put parameter description here>

Default: 128

Outputs

Change Map

[raster] <put output description here>

Console usage

processing .

runalg( ’otb:multivariatealterationdetector’ , in1, in2, ram, out)

See also

Radiometric Indices

Description

<put algortithm description here>

Parameters

Input Image

[raster] <put parameter description here>

Available RAM (Mb)

[number] <put parameter description here>

Default: 128

Blue Channel

[number] <put parameter description here>

Default: 1

Green Channel

[number] <put parameter description here>

Default: 1

Red Channel

[number] <put parameter description here>

Default: 1

NIR Channel

[number] <put parameter description here>

Default: 1

Mir Channel

[number] <put parameter description here>

Default: 1

Available Radiometric Indices

[selection] <put parameter description here>

Options:

• 0 — ndvi

• 1 — tndvi

• 2 — rvi

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• 3 — savi

• 4 — tsavi

• 5 — msavi

• 6 — msavi2

• 7 — gemi

• 8 — ipvi

• 9 — ndwi

• 10 — ndwi2

• 11 — mndwi

• 12 — ndpi

• 13 — ndti

• 14 — ri

• 15 — ci

• 16 — bi

• 17 — bi2

Default: 0

Outputs

Output Image

[raster] <put output description here>

Console usage

processing.runalg(’otb:radiometricindices’, -in, -ram, -channels.blue, -channels.green, -channels.red, -channels.nir, -channels.mir, -list, -out)

.

See also

18.4.3 Geometry

Image Envelope

Description

<put algortithm description here>

Parameters

Input Image

[raster] <put parameter description here>

Sampling Rate

[number] <put parameter description here>

Default: 0

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Projection

[string] Optional.

<put parameter description here>

Default: None

Outputs

Output Vector Data

[vector] <put output description here>

Console usage

processing.runalg(’otb:imageenvelope’, -in, -sr, -proj, -out)

See also

OrthoRectification (epsg)

Description

<put algortithm description here>

Parameters

Input Image

[raster] <put parameter description here>

Output Cartographic Map Projection

[selection] <put parameter description here>

Options:

• 0 — epsg

Default: 0

EPSG Code

[number] <put parameter description here>

Default: 4326

Parameters estimation modes

[selection] <put parameter description here>

Options:

• 0 — autosize

• 1 — autospacing

Default: 0

Default pixel value

[number] <put parameter description here>

Default: 0

Default elevation

[number] <put parameter description here>

Default: 0

Interpolation

[selection] <put parameter description here>

Options:

• 0 — bco

• 1 — nn

• 2 — linear

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Default: 0

Radius for bicubic interpolation

[number] <put parameter description here>

Default: 2

Available RAM (Mb)

[number] <put parameter description here>

Default: 128

Resampling grid spacing

[number] <put parameter description here>

Default: 4

Outputs

Output Image

[raster] <put output description here>

Console usage

processing.runalg(’otb:orthorectificationepsg’, -io.in, -map, -map.epsg.code, -outputs.mode, -outputs.default, -elev.default, -interpolator, -interpolator.bco.radius, -opt.ram, -opt.gridspacing, -io.out)

See also

OrthoRectification (fit-to-ortho)

Description

<put algortithm description here>

Parameters

Input Image

[raster] <put parameter description here>

Parameters estimation modes

[selection] <put parameter description here>

Options:

• 0 — orthofit

Default: 0

Model ortho-image

[raster] Optional.

<put parameter description here>

Default pixel value

[number] <put parameter description here>

Default: 0

Default elevation

[number] <put parameter description here>

Default: 0

Interpolation

[selection] <put parameter description here>

Options:

• 0 — bco

• 1 — nn

• 2 — linear

Default: 0

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Radius for bicubic interpolation

[number] <put parameter description here>

Default: 2

Available RAM (Mb)

[number] <put parameter description here>

Default: 128

Resampling grid spacing

[number] <put parameter description here>

Default: 4

Outputs

Output Image

[raster] <put output description here>

Console usage

processing.runalg(’otb:orthorectificationfittoortho’, -io.in, -outputs.mode, -outputs.ortho, -outputs.default, -elev.default, -interpolator, -interpolator.bco.radius, -opt.ram, -opt.gridspacing, -io.out)

See also

OrthoRectification (lambert-WGS84)

Description

<put algortithm description here>

Parameters

Input Image

[raster] <put parameter description here>

Output Cartographic Map Projection

[selection] <put parameter description here>

Options:

• 0 — lambert2

• 1 — lambert93

• 2 — wgs

Default: 0

Parameters estimation modes

[selection] <put parameter description here>

Options:

• 0 — autosize

• 1 — autospacing

Default: 0

Default pixel value

[number] <put parameter description here>

Default: 0

Default elevation

[number] <put parameter description here>

Default: 0

Interpolation

[selection] <put parameter description here>

Options:

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• 0 — bco

• 1 — nn

• 2 — linear

Default: 0

Radius for bicubic interpolation

[number] <put parameter description here>

Default: 2

Available RAM (Mb)

[number] <put parameter description here>

Default: 128

Resampling grid spacing

[number] <put parameter description here>

Default: 4

Outputs

Output Image

[raster] <put output description here>

Console usage

processing.runalg(’otb:orthorectificationlambertwgs84’, -io.in, -map, -outputs.mode, -outputs.default, -elev.default, -interpolator, -interpolator.bco.radius, -opt.ram, -opt.gridspacing, -io.out)

See also

OrthoRectification (utm)

Description

<put algortithm description here>

Parameters

Input Image

[raster] <put parameter description here>

Output Cartographic Map Projection

[selection] <put parameter description here>

Options:

• 0 — utm

Default: 0

Zone number

[number] <put parameter description here>

Default: 31

Northern Hemisphere

[boolean] <put parameter description here>

Default: True

Parameters estimation modes

[selection] <put parameter description here>

Options:

• 0 — autosize

• 1 — autospacing

Default: 0

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Default pixel value

[number] <put parameter description here>

Default: 0

Default elevation

[number] <put parameter description here>

Default: 0

Interpolation

[selection] <put parameter description here>

Options:

• 0 — bco

• 1 — nn

• 2 — linear

Default: 0

Radius for bicubic interpolation

[number] <put parameter description here>

Default: 2

Available RAM (Mb)

[number] <put parameter description here>

Default: 128

Resampling grid spacing

[number] <put parameter description here>

Default: 4

Outputs

Output Image

[raster] <put output description here>

Console usage

processing.runalg(’otb:orthorectificationutm’, -io.in, -map, -map.utm.zone, -map.utm.northhem, -outputs.mode, -outputs.default, -elev.default, -interpolator, -interpolator.bco.radius, -opt.ram, -opt.gridspacing, -io.out)

See also

Pansharpening (bayes)

Description

<put algortithm description here>

Parameters

Input PAN Image

[raster] <put parameter description here>

Input XS Image

[raster] <put parameter description here>

Algorithm

[selection] <put parameter description here>

Options:

• 0 — bayes

Default: 0

Weight

[number] <put parameter description here>

Default: 0.9999

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S coefficient

[number] <put parameter description here>

Default: 1

Available RAM (Mb)

[number] <put parameter description here>

Default: 128

Outputs

Output image

[raster] <put output description here>

Console usage

processing.runalg(’otb:pansharpeningbayes’, -inp, -inxs, -method, -method.bayes.lambda, -method.bayes.s, -ram, -out)

See also

Pansharpening (lmvm)

Description

<put algortithm description here>

Parameters

Input PAN Image

[raster] <put parameter description here>

Input XS Image

[raster] <put parameter description here>

Algorithm

[selection] <put parameter description here>

Options:

• 0 — lmvm

Default: 0

X radius

[number] <put parameter description here>

Default: 3

Y radius

[number] <put parameter description here>

Default: 3

Available RAM (Mb)

[number] <put parameter description here>

Default: 128

Outputs

Output image

[raster] <put output description here>

Console usage

processing .

runalg( ’otb:pansharpeninglmvm’ , inp, inxs, method, method .

lmvm .

radiusx, method .

lmvm .

radiusy, ram, out)

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See also

Pansharpening (rcs)

Description

<put algortithm description here>

Parameters

Input PAN Image

[raster] <put parameter description here>

Input XS Image

[raster] <put parameter description here>

Algorithm

[selection] <put parameter description here>

Options:

• 0 — rcs

Default: 0

Available RAM (Mb)

[number] <put parameter description here>

Default: 128

Outputs

Output image

[raster] <put output description here>

Console usage

processing .

runalg( ’otb:pansharpeningrcs’ , inp, inxs, method, ram, out)

See also

RigidTransformResample (id)

Description

<put algortithm description here>

Parameters

Input image

[raster] <put parameter description here>

Type of transformation

[selection] <put parameter description here>

Options:

• 0 — id

Default: 0

X scaling

[number] <put parameter description here>

Default: 1

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Y scaling

[number] <put parameter description here>

Default: 1

Interpolation

[selection] <put parameter description here>

Options:

• 0 — nn

• 1 — linear

• 2 — bco

Default: 2

Radius for bicubic interpolation

[number] <put parameter description here>

Default: 2

Available RAM (Mb)

[number] <put parameter description here>

Default: 128

Outputs

Output image

[raster] <put output description here>

Console usage

processing.runalg(’otb:rigidtransformresampleid’, -in, -transform.type, -transform.type.id.scalex, -transform.type.id.scaley, -interpolator, -interpolator.bco.radius, -ram, -out)

See also

RigidTransformResample (rotation)

Description

<put algortithm description here>

Parameters

Input image

[raster] <put parameter description here>

Type of transformation

[selection] <put parameter description here>

Options:

• 0 — rotation

Default: 0

Rotation angle

[number] <put parameter description here>

Default: 0

X scaling

[number] <put parameter description here>

Default: 1

Y scaling

[number] <put parameter description here>

Default: 1

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Interpolation

[selection] <put parameter description here>

Options:

• 0 — nn

• 1 — linear

• 2 — bco

Default: 2

Radius for bicubic interpolation

[number] <put parameter description here>

Default: 2

Available RAM (Mb)

[number] <put parameter description here>

Default: 128

Outputs

Output image

[raster] <put output description here>

Console usage

processing.runalg(’otb:rigidtransformresamplerotation’, -in, -transform.type, -transform.type.rotation.angle, -transform.type.rotation.scalex, -transform.type.rotation.scaley, -interpolator, -interpolator.bco.radius, -ram, -out)

See also

RigidTransformResample (translation)

Description

<put algortithm description here>

Parameters

Input image

[raster] <put parameter description here>

Type of transformation

[selection] <put parameter description here>

Options:

• 0 — translation

Default: 0

The X translation (in physical units)

[number] <put parameter description here>

Default: 0

The Y translation (in physical units)

[number] <put parameter description here>

Default: 0

X scaling

[number] <put parameter description here>

Default: 1

Y scaling

[number] <put parameter description here>

Default: 1

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Interpolation

[selection] <put parameter description here>

Options:

• 0 — nn

• 1 — linear

• 2 — bco

Default: 2

Radius for bicubic interpolation

[number] <put parameter description here>

Default: 2

Available RAM (Mb)

[number] <put parameter description here>

Default: 128

Outputs

Output image

[raster] <put output description here>

Console usage

processing.runalg(’otb:rigidtransformresampletranslation’, -in, -transform.type, -transform.type.translation.tx, -transform.type.translation.ty, -transform.type.translation.scalex, -transform.type.translation.scaley, -interpolator, -interpolator.bco.radius, -ram, -out)

See also

Superimpose sensor

Description

<put algortithm description here>

Parameters

Reference input

[raster] <put parameter description here>

The image to reproject

[raster] <put parameter description here>

Default elevation

[number] <put parameter description here>

Default: 0

Spacing of the deformation field

[number] <put parameter description here>

Default: 4

Interpolation

[selection] <put parameter description here>

Options:

• 0 — bco

• 1 — nn

• 2 — linear

Default: 0

Radius for bicubic interpolation

[number] <put parameter description here>

Default: 2

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Available RAM (Mb)

[number] <put parameter description here>

Default: 128

Outputs

Output image

[raster] <put output description here>

Console usage

processing .

runalg( ’otb:superimposesensor’ , inr, inm, elev .

default, lms, interpolator, interpolator .

bco .

radius, ram, out)

.

See also

18.4.4 Image filtering

DimensionalityReduction (ica)

Description

<put algortithm description here>

Parameters

Input Image

[raster] <put parameter description here>

Algorithm

[selection] <put parameter description here>

Options:

• 0 — ica

Default: 0

number of iterations

[number] <put parameter description here>

Default: 20

Give the increment weight of W in [0, 1]

[number] <put parameter description here>

Default: 1

Number of Components

[number] <put parameter description here>

Default: 0

Normalize

[boolean] <put parameter description here>

Default: True

Outputs

Output Image

[raster] <put output description here>

‘‘ Inverse Output Image‘‘ [raster] <put output description here>

Transformation matrix output

[file] <put output description here>

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Console usage

processing.runalg(’otb:dimensionalityreductionica’, -in, -method, -method.ica.iter, -method.ica.mu, -nbcomp, -normalize, -out, -outinv, -outmatrix)

See also

DimensionalityReduction (maf)

Description

<put algortithm description here>

Parameters

Input Image

[raster] <put parameter description here>

Algorithm

[selection] <put parameter description here>

Options:

• 0 — maf

Default: 0

Number of Components.

[number] <put parameter description here>

Default: 0

Normalize.

[boolean] <put parameter description here>

Default: True

Outputs

Output Image

[raster] <put output description here>

Transformation matrix output

[file] <put output description here>

Console usage

processing.runalg(’otb:dimensionalityreductionmaf’, -in, -method, -nbcomp, -normalize, -out, -outmatrix)

See also

DimensionalityReduction (napca)

Description

<put algortithm description here>

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Parameters

Input Image

[raster] <put parameter description here>

Algorithm

[selection] <put parameter description here>

Options:

• 0 — napca

Default: 0

Set the x radius of the sliding window.

[number] <put parameter description here>

Default: 1

Set the y radius of the sliding window.

[number] <put parameter description here>

Default: 1

Number of Components.

[number] <put parameter description here>

Default: 0

Normalize.

[boolean] <put parameter description here>

Default: True

Outputs

Output Image

[raster] <put output description here>

‘‘ Inverse Output Image‘‘ [raster] <put output description here>

Transformation matrix output

[file] <put output description here>

Console usage

processing.runalg(’otb:dimensionalityreductionnapca’, -in, -method, -method.napca.radiusx, -method.napca.radiusy, -nbcomp, -normalize, -out, -outinv, -outmatrix)

See also

DimensionalityReduction (pca)

Description

<put algortithm description here>

Parameters

Input Image

[raster] <put parameter description here>

Algorithm

[selection] <put parameter description here>

Options:

• 0 — pca

Default: 0

Number of Components.

[number] <put parameter description here>

Default: 0

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Normalize.

[boolean] <put parameter description here>

Default: True

Outputs

Output Image

[raster] <put output description here>

‘‘ Inverse Output Image‘‘ [raster] <put output description here>

Transformation matrix output

[file] <put output description here>

Console usage

processing.runalg(’otb:dimensionalityreductionpca’, -in, -method, -nbcomp, -normalize, -out, -outinv, -outmatrix)

See also

Mean Shift filtering (can be used as Exact Large-Scale Mean-Shift segmentation, step 1)

Description

<put algortithm description here>

Parameters

Input Image

[raster] <put parameter description here>

Spatial radius

[number] <put parameter description here>

Default: 5

Range radius

[number] <put parameter description here>

Default: 15

Mode convergence threshold

[number] <put parameter description here>

Default: 0.1

Maximum number of iterations

[number] <put parameter description here>

Default: 100

Range radius coefficient

[number] <put parameter description here>

Default: 0

Mode search.

[boolean] <put parameter description here>

Default: True

Outputs

Filtered output

[raster] <put output description here>

Spatial image

[raster] <put output description here>

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Console usage

processing.runalg(’otb:meanshiftfilteringcanbeusedasexactlargescalemeanshiftsegmentationstep1’, -in, -spatialr, -ranger, -thres, -maxiter, -rangeramp, -modesearch, -fout, -foutpos)

See also

Smoothing (anidif)

Description

<put algortithm description here>

Parameters

Input Image

[raster] <put parameter description here>

Available RAM (Mb)

[number] <put parameter description here>

Default: 128

Smoothing Type

[selection] <put parameter description here>

Options:

• 0 — anidif

Default: 2

Time Step

[number] <put parameter description here>

Default: 0.125

Nb Iterations

[number] <put parameter description here>

Default: 10

Outputs

Output Image

[raster] <put output description here>

Console usage

processing.runalg(’otb:smoothinganidif’, -in, -ram, -type, -type.anidif.timestep, -type.anidif.nbiter, -out)

See also

Smoothing (gaussian)

Description

<put algortithm description here>

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Parameters

Input Image

[raster] <put parameter description here>

Available RAM (Mb)

[number] <put parameter description here>

Default: 128

Smoothing Type

[selection] <put parameter description here>

Options:

• 0 — gaussian

Default: 2

Radius

[number] <put parameter description here>

Default: 2

Outputs

Output Image

[raster] <put output description here>

Console usage

processing.runalg(’otb:smoothinggaussian’, -in, -ram, -type, -type.gaussian.radius, -out)

See also

Smoothing (mean)

Description

<put algortithm description here>

Parameters

Input Image

[raster] <put parameter description here>

Available RAM (Mb)

[number] <put parameter description here>

Default: 128

Smoothing Type

[selection] <put parameter description here>

Options:

• 0 — mean

Default: 2

Radius

[number] <put parameter description here>

Default: 2

Outputs

Output Image

[raster] <put output description here>

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Console usage

processing.runalg(’otb:smoothingmean’, -in, -ram, -type, -type.mean.radius, -out)

.

See also

18.4.5 Image manipulation

ColorMapping (continuous)

Description

<put algortithm description here>

Parameters

Input Image

[raster] <put parameter description here>

Available RAM (Mb)

[number] <put parameter description here>

Default: 128

Operation

[selection] <put parameter description here>

Options:

• 0 — labeltocolor

Default: 0

Color mapping method

[selection] <put parameter description here>

Options:

• 0 — continuous

Default: 0

Look-up tables

[selection] <put parameter description here>

Options:

• 0 — red

• 1 — green

• 2 — blue

• 3 — grey

• 4 — hot

• 5 — cool

• 6 — spring

• 7 — summer

• 8 — autumn

• 9 — winter

• 10 — copper

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• 11 — jet

• 12 — hsv

• 13 — overunder

• 14 — relief

Default: 0

Mapping range lower value

[number] <put parameter description here>

Default: 0

Mapping range higher value

[number] <put parameter description here>

Default: 255

Outputs

Output Image

[raster] <put output description here>

Console usage

processing.runalg(’otb:colormappingcontinuous’, -in, -ram, -op, -method, -method.continuous.lut, -method.continuous.min, -method.continuous.max, -out)

See also

ColorMapping (custom)

Description

<put algortithm description here>

Parameters

Input Image

[raster] <put parameter description here>

Available RAM (Mb)

[number] <put parameter description here>

Default: 128

Operation

[selection] <put parameter description here>

Options:

• 0 — labeltocolor

Default: 0

Color mapping method

[selection] <put parameter description here>

Options:

• 0 — custom

Default: 0

Look-up table file

[file] <put parameter description here>

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Outputs

Output Image

[raster] <put output description here>

Console usage

processing.runalg(’otb:colormappingcustom’, -in, -ram, -op, -method, -method.custom.lut, -out)

See also

ColorMapping (image)

Description

<put algortithm description here>

Parameters

Input Image

[raster] <put parameter description here>

Available RAM (Mb)

[number] <put parameter description here>

Default: 128

Operation

[selection] <put parameter description here>

Options:

• 0 — labeltocolor

Default: 0

Color mapping method

[selection] <put parameter description here>

Options:

• 0 — image

Default: 0

Support Image

[raster] <put parameter description here>

NoData value

[number] <put parameter description here>

Default: 0

lower quantile

[number] <put parameter description here>

Default: 2

upper quantile

[number] <put parameter description here>

Default: 2

Outputs

Output Image

[raster] <put output description here>

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Console usage

processing.runalg(’otb:colormappingimage’, -in, -ram, -op, -method, -method.image.in, -method.image.nodatavalue, -method.image.low, -method.image.up, -out)

See also

ColorMapping (optimal)

Description

<put algortithm description here>

Parameters

Input Image

[raster] <put parameter description here>

Available RAM (Mb)

[number] <put parameter description here>

Default: 128

Operation

[selection] <put parameter description here>

Options:

• 0 — labeltocolor

Default: 0

Color mapping method

[selection] <put parameter description here>

Options:

• 0 — optimal

Default: 0

Background label

[number] <put parameter description here>

Default: 0

Outputs

Output Image

[raster] <put output description here>

Console usage

processing.runalg(’otb:colormappingoptimal’, -in, -ram, -op, -method, -method.optimal.background, -out)

See also

ExtractROI (fit)

Description

<put algortithm description here>

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Parameters

Input Image

[raster] <put parameter description here>

Available RAM (Mb)

[number] <put parameter description here>

Default: 128

Extraction mode

[selection] <put parameter description here>

Options:

• 0 — fit

Default: 0

Reference image

[raster] <put parameter description here>

Default elevation

[number] <put parameter description here>

Default: 0

Outputs

Output Image

[raster] <put output description here>

Console usage

processing.runalg(’otb:extractroifit’, -in, -ram, -mode, -mode.fit.ref, -mode.fit.elev.default, -out)

See also

ExtractROI (standard)

Description

<put algortithm description here>

Parameters

Input Image

[raster] <put parameter description here>

Available RAM (Mb)

[number] <put parameter description here>

Default: 128

Extraction mode

[selection] <put parameter description here>

Options:

• 0 — standard

Default: 0

Start X

[number] <put parameter description here>

Default: 0

Start Y

[number] <put parameter description here>

Default: 0

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Size X

[number] <put parameter description here>

Default: 0

Size Y

[number] <put parameter description here>

Default: 0

Outputs

Output Image

[raster] <put output description here>

Console usage

processing.runalg(’otb:extractroistandard’, -in, -ram, -mode, -startx, -starty, -sizex, -sizey, -out)

See also

Images Concatenation

Description

<put algortithm description here>

Parameters

Input images list

[multipleinput: rasters] <put parameter description here>

Available RAM (Mb)

[number] <put parameter description here>

Default: 128

Outputs

Output Image

[raster] <put output description here>

Console usage

processing .

runalg( ’otb:imagesconcatenation’ , il, ram, out)

See also

Image Tile Fusion

Description

<put algortithm description here>

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Parameters

Input Tile Images

[multipleinput: rasters] <put parameter description here>

Number of tile columns

[number] <put parameter description here>

Default: 0

Number of tile rows

[number] <put parameter description here>

Default: 0

Outputs

Output Image

[raster] <put output description here>

Console usage

processing .

runalg( ’otb:imagetilefusion’ , il, cols, rows, out)

See also

Read image information

Description

<put algortithm description here>

Parameters

Input Image

[raster] <put parameter description here>

Display the OSSIM keywordlist

[boolean] <put parameter description here>

Default: True

GCPs Id

[string] <put parameter description here>

Default: None

GCPs Info

[string] <put parameter description here>

Default: None

GCPs Image Coordinates

[string] <put parameter description here>

Default: None

GCPs Geographic Coordinates

[string] <put parameter description here>

Default: None

Outputs

Console usage

processing.runalg(’otb:readimageinformation’, -in, -keywordlist, -gcp.ids, -gcp.info, -gcp.imcoord, -gcp.geocoord)

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See also

Rescale Image

Description

<put algortithm description here>

Parameters

Input Image

[raster] <put parameter description here>

Available RAM (Mb)

[number] <put parameter description here>

Default: 128

Output min value

[number] <put parameter description here>

Default: 0

Output max value

[number] <put parameter description here>

Default: 255

Outputs

Output Image

[raster] <put output description here>

Console usage

processing.runalg(’otb:rescaleimage’, -in, -ram, -outmin, -outmax, -out)

See also

Split Image

Description

<put algortithm description here>

Parameters

Input Image

[raster] <put parameter description here>

Available RAM (Mb)

[number] <put parameter description here>

Default: 128

Outputs

Output Image

[file] <put output description here>

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Console usage

processing.runalg(’otb:splitimage’, -in, -ram, -out)

.

See also

18.4.6 Learning

Classification Map Regularization

Description

<put algortithm description here>

Parameters

Input classification image

[raster] <put parameter description here>

Structuring element radius (in pixels)

[number] <put parameter description here>

Default: 1

Multiple majority: Undecided(X)/Original

[boolean] <put parameter description here>

Default: True

Label for the NoData class

[number] <put parameter description here>

Default: 0

Label for the Undecided class

[number] <put parameter description here>

Default: 0

Available RAM (Mb)

[number] <put parameter description here>

Default: 128

Outputs

Output regularized image

[raster] <put output description here>

Console usage

processing.runalg(’otb:classificationmapregularization’, -io.in, -ip.radius, -ip.suvbool, -ip.nodatalabel, -ip.undecidedlabel, -ram, -io.out)

See also

ComputeConfusionMatrix (raster)

Description

<put algortithm description here>

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Parameters

Input Image

[raster] <put parameter description here>

Ground truth

[selection] <put parameter description here>

Options:

• 0 — raster

Default: 0

Input reference image

[raster] <put parameter description here>

Value for nodata pixels

[number] <put parameter description here>

Default: 0

Available RAM (Mb)

[number] <put parameter description here>

Default: 128

Outputs

Matrix output

[file] <put output description here>

Console usage

processing.runalg(’otb:computeconfusionmatrixraster’, -in, -ref, -ref.raster.in, -nodatalabel, -ram, -out)

See also

ComputeConfusionMatrix (vector)

Description

<put algortithm description here>

Parameters

Input Image

[raster] <put parameter description here>

Ground truth

[selection] <put parameter description here>

Options:

• 0 — vector

Default: 0

Input reference vector data

[file] <put parameter description here>

Field name

[string] Optional.

<put parameter description here>

Default: Class

Value for nodata pixels

[number] <put parameter description here>

Default: 0

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Available RAM (Mb)

[number] <put parameter description here>

Default: 128

Outputs

Matrix output

[file] <put output description here>

Console usage

processing.runalg(’otb:computeconfusionmatrixvector’, -in, -ref, -ref.vector.in, -ref.vector.field, -nodatalabel, -ram, -out)

See also

Compute Images second order statistics

Description

<put algortithm description here>

Parameters

Input images

[multipleinput: rasters] <put parameter description here>

Background Value

[number] <put parameter description here>

Default: 0.0

Outputs

Output XML file

[file] <put output description here>

Console usage

processing .

runalg( ’otb:computeimagessecondorderstatistics’ , il, bv, out)

See also

FusionOfClassifications (dempstershafer)

Description

<put algortithm description here>

Parameters

Input classifications

[multipleinput: rasters] <put parameter description here>

Fusion method

[selection] <put parameter description here>

Options:

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• 0 — dempstershafer

Default: 0

Confusion Matrices

[multipleinput: files] <put parameter description here>

Mass of belief measurement

[selection] <put parameter description here>

Options:

• 0 — precision

• 1 — recall

• 2 — accuracy

• 3 — kappa

Default: 0

Label for the NoData class

[number] <put parameter description here>

Default: 0

Label for the Undecided class

[number] <put parameter description here>

Default: 0

Outputs

The output classification image

[raster] <put output description here>

Console usage

processing .

runalg( ’otb:fusionofclassificationsdempstershafer’ , il, method, method .

dempstershafer .

cmfl, method .

dempstershafer .

mob, nodatalabel, undecidedlabel, out)

See also

FusionOfClassifications (majorityvoting)

Description

<put algortithm description here>

Parameters

Input classifications

[multipleinput: rasters] <put parameter description here>

Fusion method

[selection] <put parameter description here>

Options:

• 0 — majorityvoting

Default: 0

Label for the NoData class

[number] <put parameter description here>

Default: 0

Label for the Undecided class

[number] <put parameter description here>

Default: 0

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Outputs

The output classification image

[raster] <put output description here>

Console usage

processing .

runalg( ’otb:fusionofclassificationsmajorityvoting’ , il, method, nodatalabel, undecidedlabel, out)

See also

Image Classification

Description

<put algortithm description here>

Parameters

Input Image

[raster] <put parameter description here>

Input Mask

[raster] Optional.

<put parameter description here>

Model file

[file] <put parameter description here>

Statistics file

[file] Optional.

<put parameter description here>

Available RAM (Mb)

[number] <put parameter description here>

Default: 128

Outputs

Output Image

[raster] <put output description here>

Console usage

processing.runalg(’otb:imageclassification’, -in, -mask, -model, -imstat, -ram, -out)

See also

SOM Classification

Description

<put algortithm description here>

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Parameters

InputImage

[raster] <put parameter description here>

ValidityMask

[raster] Optional.

<put parameter description here>

TrainingProbability

[number] <put parameter description here>

Default: 1

TrainingSetSize

[number] <put parameter description here>

Default: 0

StreamingLines

[number] <put parameter description here>

Default: 0

SizeX

[number] <put parameter description here>

Default: 32

SizeY

[number] <put parameter description here>

Default: 32

NeighborhoodX

[number] <put parameter description here>

Default: 10

NeighborhoodY

[number] <put parameter description here>

Default: 10

NumberIteration

[number] <put parameter description here>

Default: 5

BetaInit

[number] <put parameter description here>

Default: 1

BetaFinal

[number] <put parameter description here>

Default: 0.1

InitialValue

[number] <put parameter description here>

Default: 0

Available RAM (Mb)

[number] <put parameter description here>

Default: 128

set user defined seed

[number] <put parameter description here>

Default: 0

Outputs

OutputImage

[raster] <put output description here>

SOM Map

[raster] <put output description here>

Console usage

processing.runalg(’otb:somclassification’, -in, -vm, -tp, -ts, -sl, -sx, -sy, -nx, -ny, -ni, -bi, -bf, -iv, -ram, -rand, -out, -som)

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See also

TrainImagesClassifier (ann)

Description

<put algortithm description here>

Parameters

Input Image List

[multipleinput: rasters] <put parameter description here>

Input Vector Data List

[multipleinput: any vectors] <put parameter description here>

Input XML image statistics file

[file] Optional.

<put parameter description here>

Default elevation

[number] <put parameter description here>

Default: 0

Maximum training sample size per class

[number] <put parameter description here>

Default: 1000

Maximum validation sample size per class

[number] <put parameter description here>

Default: 1000

On edge pixel inclusion

[boolean] <put parameter description here>

Default: True

Training and validation sample ratio

[number] <put parameter description here>

Default: 0.5

Name of the discrimination field

[string] <put parameter description here>

Default: Class

Classifier to use for the training

[selection] <put parameter description here>

Options:

• 0 — ann

Default: 0

Train Method Type

[selection] <put parameter description here>

Options:

• 0 — reg

• 1 — back

Default: 0

Number of neurons in each intermediate layer

[string] <put parameter description here>

Default: None

Neuron activation function type

[selection] <put parameter description here>

Options:

• 0 — ident

• 1 — sig

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• 2 — gau

Default: 1

Alpha parameter of the activation function

[number] <put parameter description here>

Default: 1

Beta parameter of the activation function

[number] <put parameter description here>

Default: 1

Strength of the weight gradient term in the BACKPROP method

[number] <put parameter description here>

Default: 0.1

Strength of the momentum term (the difference between weights on the 2 previous iterations)

[number]

<put parameter description here>

Default: 0.1

Initial value Delta_0 of update-values Delta_{ij} in RPROP method

[number]

<put parameter description here>

Default: 0.1

Update-values lower limit Delta_{min} in RPROP method

[number] <put parameter description here>

Default: 1e-07

Termination criteria

[selection] <put parameter description here>

Options:

• 0 — iter

• 1 — eps

• 2 — all

Default: 2

Epsilon value used in the Termination criteria

[number] <put parameter description here>

Default: 0.01

Maximum number of iterations used in the Termination criteria

[number] <put parameter description here>

Default: 1000

set user defined seed

[number] <put parameter description here>

Default: 0

Outputs

Output confusion matrix

[file] <put output description here>

Output model

[file] <put output description here>

Console usage

processing .

runalg( ’otb:trainimagesclassifierann’ , io .

il, io .

vd, io .

imstat, elev .

default, sample .

mt, sample .

mv, sample .

edg, sample .

vtr, sample .

vfn, classifier, classifier .

ann .

t, classifier .

ann .

sizes, classifier .

ann .

f, classifier .

ann .

a, classifier .

ann .

b, classifier .

ann .

bpdw, classifier .

ann .

bpms, classifier .

ann .

rdw, classifier .

ann .

rdwm, classifier .

ann .

term, classifier .

ann .

eps, classifier .

ann .

iter, rand, io .

confmatout, io .

out)

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See also

TrainImagesClassifier (bayes)

Description

<put algortithm description here>

Parameters

Input Image List

[multipleinput: rasters] <put parameter description here>

Input Vector Data List

[multipleinput: any vectors] <put parameter description here>

Input XML image statistics file

[file] Optional.

<put parameter description here>

Default elevation

[number] <put parameter description here>

Default: 0

Maximum training sample size per class

[number] <put parameter description here>

Default: 1000

Maximum validation sample size per class

[number] <put parameter description here>

Default: 1000

On edge pixel inclusion

[boolean] <put parameter description here>

Default: True

Training and validation sample ratio

[number] <put parameter description here>

Default: 0.5

Name of the discrimination field

[string] <put parameter description here>

Default: Class

Classifier to use for the training

[selection] <put parameter description here>

Options:

• 0 — bayes

Default: 0

set user defined seed

[number] <put parameter description here>

Default: 0

Outputs

Output confusion matrix

[file] <put output description here>

Output model

[file] <put output description here>

Console usage

processing .

runalg( ’otb:trainimagesclassifierbayes’ , io .

il, io .

vd, io .

imstat, elev .

default, sample .

mt, sample .

mv, sample .

edg, sample .

vtr, sample .

vfn, classifier, rand, io .

confmatout, io .

out)

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See also

TrainImagesClassifier (boost)

Description

<put algortithm description here>

Parameters

Input Image List

[multipleinput: rasters] <put parameter description here>

Input Vector Data List

[multipleinput: any vectors] <put parameter description here>

Input XML image statistics file

[file] Optional.

<put parameter description here>

Default elevation

[number] <put parameter description here>

Default: 0

Maximum training sample size per class

[number] <put parameter description here>

Default: 1000

Maximum validation sample size per class

[number] <put parameter description here>

Default: 1000

On edge pixel inclusion

[boolean] <put parameter description here>

Default: True

Training and validation sample ratio

[number] <put parameter description here>

Default: 0.5

Name of the discrimination field

[string] <put parameter description here>

Default: Class

Classifier to use for the training

[selection] <put parameter description here>

Options:

• 0 — boost

Default: 0

Boost Type

[selection] <put parameter description here>

Options:

• 0 — discrete

• 1 — real

• 2 — logit

• 3 — gentle

Default: 1

Weak count

[number] <put parameter description here>

Default: 100

Weight Trim Rate

[number] <put parameter description here>

Default: 0.95

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Maximum depth of the tree

[number] <put parameter description here>

Default: 1

set user defined seed

[number] <put parameter description here>

Default: 0

Outputs

Output confusion matrix

[file] <put output description here>

Output model

[file] <put output description here>

Console usage

processing .

runalg( ’otb:trainimagesclassifierboost’ , io .

il, io .

vd, io .

imstat, elev .

default, sample .

mt, sample .

mv, sample .

edg, sample .

vtr, sample .

vfn, classifier, classifier .

boost .

t, classifier .

boost .

w, classifier .

boost .

r, classifier .

boost .

m, rand, io .

confmatout, io .

out)

See also

TrainImagesClassifier (dt)

Description

<put algortithm description here>

Parameters

Input Image List

[multipleinput: rasters] <put parameter description here>

Input Vector Data List

[multipleinput: any vectors] <put parameter description here>

Input XML image statistics file

[file] Optional.

<put parameter description here>

Default elevation

[number] <put parameter description here>

Default: 0

Maximum training sample size per class

[number] <put parameter description here>

Default: 1000

Maximum validation sample size per class

[number] <put parameter description here>

Default: 1000

On edge pixel inclusion

[boolean] <put parameter description here>

Default: True

Training and validation sample ratio

[number] <put parameter description here>

Default: 0.5

Name of the discrimination field

[string] <put parameter description here>

Default: Class

Classifier to use for the training

[selection] <put parameter description here>

Options:

• 0 — dt

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Default: 0

Maximum depth of the tree

[number] <put parameter description here>

Default: 65535

Minimum number of samples in each node

[number] <put parameter description here>

Default: 10

Termination criteria for regression tree

[number] <put parameter description here>

Default: 0.01

Cluster possible values of a categorical variable into K <= cat clusters to find a suboptimal split

[number]

<put parameter description here>

Default: 10

K-fold cross-validations

[number] <put parameter description here>

Default: 10

Set Use1seRule flag to false

[boolean] <put parameter description here>

Default: True

Set TruncatePrunedTree flag to false

[boolean] <put parameter description here>

Default: True

set user defined seed

[number] <put parameter description here>

Default: 0

Outputs

Output confusion matrix

[file] <put output description here>

Output model

[file] <put output description here>

Console usage

processing .

runalg( ’otb:trainimagesclassifierdt’ , io .

il, io .

vd, io .

imstat, elev .

default, sample .

mt, sample .

mv, sample .

edg, sample .

vtr, sample .

vfn, classifier, classifier .

dt .

max, classifier .

dt .

min, classifier .

dt .

ra, classifier .

dt .

cat, classifier .

dt .

f, classifier .

dt .

r, classifier .

dt .

t, rand, io .

confmatout, io .

out)

See also

TrainImagesClassifier (gbt)

Description

<put algortithm description here>

Parameters

Input Image List

[multipleinput: rasters] <put parameter description here>

Input Vector Data List

[multipleinput: any vectors] <put parameter description here>

Input XML image statistics file

[file] Optional.

<put parameter description here>

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Default elevation

[number] <put parameter description here>

Default: 0

Maximum training sample size per class

[number] <put parameter description here>

Default: 1000

Maximum validation sample size per class

[number] <put parameter description here>

Default: 1000

On edge pixel inclusion

[boolean] <put parameter description here>

Default: True

Training and validation sample ratio

[number] <put parameter description here>

Default: 0.5

Name of the discrimination field

[string] <put parameter description here>

Default: Class

Classifier to use for the training

[selection] <put parameter description here>

Options:

• 0 — gbt

Default: 0

Number of boosting algorithm iterations

[number] <put parameter description here>

Default: 200

Regularization parameter

[number] <put parameter description here>

Default: 0.01

Portion of the whole training set used for each algorithm iteration

[number]

<put parameter description here>

Default: 0.8

Maximum depth of the tree

[number] <put parameter description here>

Default: 3

set user defined seed

[number] <put parameter description here>

Default: 0

Outputs

Output confusion matrix

[file] <put output description here>

Output model

[file] <put output description here>

Console usage

processing .

runalg( ’otb:trainimagesclassifiergbt’ , io .

il, io .

vd, io .

imstat, elev .

default, sample .

mt, sample .

mv, sample .

edg, sample .

vtr, sample .

vfn, classifier, classifier .

gbt .

w, classifier .

gbt .

s, classifier .

gbt .

p, classifier .

gbt .

max, rand, io .

confmatout, io .

out)

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See also

TrainImagesClassifier (knn)

Description

<put algortithm description here>

Parameters

Input Image List

[multipleinput: rasters] <put parameter description here>

Input Vector Data List

[multipleinput: any vectors] <put parameter description here>

Input XML image statistics file

[file] Optional.

<put parameter description here>

Default elevation

[number] <put parameter description here>

Default: 0

Maximum training sample size per class

[number] <put parameter description here>

Default: 1000

Maximum validation sample size per class

[number] <put parameter description here>

Default: 1000

On edge pixel inclusion

[boolean] <put parameter description here>

Default: True

Training and validation sample ratio

[number] <put parameter description here>

Default: 0.5

Name of the discrimination field

[string] <put parameter description here>

Default: Class

Classifier to use for the training

[selection] <put parameter description here>

Options:

• 0 — knn

Default: 0

Number of Neighbors

[number] <put parameter description here>

Default: 32

set user defined seed

[number] <put parameter description here>

Default: 0

Outputs

Output confusion matrix

[file] <put output description here>

Output model

[file] <put output description here>

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Console usage

processing .

runalg( ’otb:trainimagesclassifierknn’ , io .

il, io .

vd, io .

imstat, elev .

default, sample .

mt, sample .

mv, sample .

edg, sample .

vtr, sample .

vfn, classifier, classifier .

knn .

k, rand, io .

confmatout, io .

out)

See also

TrainImagesClassifier (libsvm)

Description

<put algortithm description here>

Parameters

Input Image List

[multipleinput: rasters] <put parameter description here>

Input Vector Data List

[multipleinput: any vectors] <put parameter description here>

Input XML image statistics file

[file] Optional.

<put parameter description here>

Default elevation

[number] <put parameter description here>

Default: 0

Maximum training sample size per class

[number] <put parameter description here>

Default: 1000

Maximum validation sample size per class

[number] <put parameter description here>

Default: 1000

On edge pixel inclusion

[boolean] <put parameter description here>

Default: True

Training and validation sample ratio

[number] <put parameter description here>

Default: 0.5

Name of the discrimination field

[string] <put parameter description here>

Default: Class

Classifier to use for the training

[selection] <put parameter description here>

Options:

• 0 — libsvm

Default: 0

SVM Kernel Type

[selection] <put parameter description here>

Options:

• 0 — linear

• 1 — rbf

• 2 — poly

• 3 — sigmoid

Default: 0

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Cost parameter C

[number] <put parameter description here>

Default: 1

Parameters optimization

[boolean] <put parameter description here>

Default: True

set user defined seed

[number] <put parameter description here>

Default: 0

Outputs

Output confusion matrix

[file] <put output description here>

Output model

[file] <put output description here>

Console usage

processing .

runalg( ’otb:trainimagesclassifierlibsvm’ , io .

il, io .

vd, io .

imstat, elev .

default, sample .

mt, sample .

mv, sample .

edg, sample .

vtr, sample .

vfn, classifier, classifier .

libsvm .

k, classifier .

libsvm .

c, classifier .

libsvm .

opt, rand, io .

confmatout, io .

out)

See also

TrainImagesClassifier (rf)

Description

<put algortithm description here>

Parameters

Input Image List

[multipleinput: rasters] <put parameter description here>

Input Vector Data List

[multipleinput: any vectors] <put parameter description here>

Input XML image statistics file

[file] Optional.

<put parameter description here>

Default elevation

[number] <put parameter description here>

Default: 0

Maximum training sample size per class

[number] <put parameter description here>

Default: 1000

Maximum validation sample size per class

[number] <put parameter description here>

Default: 1000

On edge pixel inclusion

[boolean] <put parameter description here>

Default: True

Training and validation sample ratio

[number] <put parameter description here>

Default: 0.5

Name of the discrimination field

[string] <put parameter description here>

Default: Class

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Classifier to use for the training

[selection] <put parameter description here>

Options:

• 0 — rf

Default: 0

Maximum depth of the tree

[number] <put parameter description here>

Default: 5

Minimum number of samples in each node

[number] <put parameter description here>

Default: 10

Termination Criteria for regression tree

[number] <put parameter description here>

Default: 0

Cluster possible values of a categorical variable into K <= cat clusters to find a suboptimal split

[number]

<put parameter description here>

Default: 10

Size of the randomly selected subset of features at each tree node

[number]

<put parameter description here>

Default: 0

Maximum number of trees in the forest

[number] <put parameter description here>

Default: 100

Sufficient accuracy (OOB error)

[number] <put parameter description here>

Default: 0.01

set user defined seed

[number] <put parameter description here>

Default: 0

Outputs

Output confusion matrix

[file] <put output description here>

Output model

[file] <put output description here>

Console usage

processing .

runalg( ’otb:trainimagesclassifierrf’ , io .

il, io .

vd, io .

imstat, elev .

default, sample .

mt, sample .

mv, sample .

edg, sample .

vtr, sample .

vfn, classifier, classifier .

rf .

max, classifier .

rf .

min, classifier .

rf .

ra, classifier .

rf .

cat, classifier .

rf .

var, classifier .

rf .

nbtrees, classifier .

rf .

acc, rand, io .

confmatout, io .

out)

See also

TrainImagesClassifier (svm)

Description

<put algortithm description here>

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Parameters

Input Image List

[multipleinput: rasters] <put parameter description here>

Input Vector Data List

[multipleinput: any vectors] <put parameter description here>

Input XML image statistics file

[file] Optional.

<put parameter description here>

Default elevation

[number] <put parameter description here>

Default: 0

Maximum training sample size per class

[number] <put parameter description here>

Default: 1000

Maximum validation sample size per class

[number] <put parameter description here>

Default: 1000

On edge pixel inclusion

[boolean] <put parameter description here>

Default: True

Training and validation sample ratio

[number] <put parameter description here>

Default: 0.5

Name of the discrimination field

[string] <put parameter description here>

Default: Class

Classifier to use for the training

[selection] <put parameter description here>

Options:

• 0 — svm

Default: 0

SVM Model Type

[selection] <put parameter description here>

Options:

• 0 — csvc

• 1 — nusvc

• 2 — oneclass

Default: 0

SVM Kernel Type

[selection] <put parameter description here>

Options:

• 0 — linear

• 1 — rbf

• 2 — poly

• 3 — sigmoid

Default: 0

Cost parameter C

[number] <put parameter description here>

Default: 1

Parameter nu of a SVM optimization problem (NU_SVC / ONE_CLASS)

[number] <put parameter description here>

Default: 0

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Parameter coef0 of a kernel function (POLY / SIGMOID)

[number] <put parameter description here>

Default: 0

Parameter gamma of a kernel function (POLY / RBF / SIGMOID)

[number] <put parameter description here>

Default: 1

Parameter degree of a kernel function (POLY)

[number] <put parameter description here>

Default: 1

Parameters optimization

[boolean] <put parameter description here>

Default: True

set user defined seed

[number] <put parameter description here>

Default: 0

Outputs

Output confusion matrix

[file] <put output description here>

Output model

[file] <put output description here>

Console usage

processing .

runalg( ’otb:trainimagesclassifiersvm’ , io .

il, io .

vd, io .

imstat, elev .

default, sample .

mt, sample .

mv, sample .

edg, sample .

vtr, sample .

vfn, classifier, classifier .

svm .

m, classifier .

svm .

k, classifier .

svm .

c, classifier .

svm .

nu, classifier .

svm .

coef0, classifier .

svm .

gamma, classifier .

svm .

degree, classifier .

svm .

opt, rand, io .

confmatout, io .

out)

See also

Unsupervised KMeans image classification

Description

<put algortithm description here>

Parameters

Input Image

[raster] <put parameter description here>

Available RAM (Mb)

[number] <put parameter description here>

Default: 128

Validity Mask

[raster] Optional.

<put parameter description here>

Training set size

[number] <put parameter description here>

Default: 100

Number of classes

[number] <put parameter description here>

Default: 5

Maximum number of iterations

[number] <put parameter description here>

Default: 1000

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Convergence threshold

[number] <put parameter description here>

Default: 0.0001

Outputs

Output Image

[raster] <put output description here>

Centroid filename

[file] <put output description here>

Console usage

processing.runalg(’otb:unsupervisedkmeansimageclassification’, -in, -ram, -vm, -ts, -nc, -maxit, -ct, -out, -outmeans)

.

See also

18.4.7 Miscellaneous

Band Math

Description

<put algortithm description here>

Parameters

Input image list

[multipleinput: rasters] <put parameter description here>

Available RAM (Mb)

[number] <put parameter description here>

Default: 128

Expression

[string] <put parameter description here>

Default: None

Outputs

Output Image

[raster] <put output description here>

Console usage

processing .

runalg( ’otb:bandmath’ , il, ram, exp, out)

See also

ComputeModulusAndPhase-one (OneEntry)

Description

<put algortithm description here>

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Parameters

Number Of inputs

[selection] <put parameter description here>

Options:

• 0 — one

Default: 0

Input image

[raster] <put parameter description here>

Available RAM (Mb)

[number] <put parameter description here>

Default: 128

Outputs

Modulus

[raster] <put output description here>

Phase

[raster] <put output description here>

Console usage

processing.runalg(’otb:computemodulusandphaseoneoneentry’, -nbinput, -nbinput.one.in, -ram, -mod, -pha)

See also

ComputeModulusAndPhase-two (TwoEntries)

Description

<put algortithm description here>

Parameters

Number Of inputs

[selection] <put parameter description here>

Options:

• 0 — two

Default: 0

Real part input

[raster] <put parameter description here>

Imaginary part input

[raster] <put parameter description here>

Available RAM (Mb)

[number] <put parameter description here>

Default: 128

Outputs

Modulus

[raster] <put output description here>

Phase

[raster] <put output description here>

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Console usage

processing .

runalg( ’otb:computemodulusandphasetwotwoentries’ , nbinput, nbinput .

two .

re, nbinput .

two .

im, ram, mod, pha)

See also

Images comparaison

Description

<put algortithm description here>

Parameters

Reference image

[raster] <put parameter description here>

Reference image channel

[number] <put parameter description here>

Default: 1

Measured image

[raster] <put parameter description here>

Measured image channel

[number] <put parameter description here>

Default: 1

Start X

[number] <put parameter description here>

Default: 0

Start Y

[number] <put parameter description here>

Default: 0

Size X

[number] <put parameter description here>

Default: 0

Size Y

[number] <put parameter description here>

Default: 0

Outputs

Console usage

processing.runalg(’otb:imagescomparaison’, -ref.in, -ref.channel, -meas.in, -meas.channel, -roi.startx, -roi.starty, -roi.sizex, -roi.sizey)

See also

Image to KMZ Export

Description

<put algortithm description here>

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Parameters

Input image

[raster] <put parameter description here>

Tile Size

[number] <put parameter description here>

Default: 512

Image logo

[raster] Optional.

<put parameter description here>

Image legend

[raster] Optional.

<put parameter description here>

Default elevation

[number] <put parameter description here>

Default: 0

Outputs

Output .kmz product

[file] <put output description here>

Console usage

processing.runalg(’otb:imagetokmzexport’, -in, -tilesize, -logo, -legend, -elev.default, -out)

.

See also

18.4.8 Segmentation

Connected Component Segmentation

Description

<put algortithm description here>

Parameters

Input Image

[raster] <put parameter description here>

Mask expression

[string] Optional.

<put parameter description here>

Default: None

Connected Component Expression

[string] <put parameter description here>

Default: None

Minimum Object Size

[number] <put parameter description here>

Default: 2

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OBIA Expression

[string] Optional.

<put parameter description here>

Default: None

Default elevation

[number] <put parameter description here>

Default: 0

Outputs

Output Shape

[vector] <put output description here>

Console usage

processing.runalg(’otb:connectedcomponentsegmentation’, -in, -mask, -expr, -minsize, -obia, -elev.default, -out)

See also

Exact Large-Scale Mean-Shift segmentation, step 2

Description

<put algortithm description here>

Parameters

Filtered image

[raster] <put parameter description here>

Spatial image

[raster] Optional.

<put parameter description here>

Range radius

[number] <put parameter description here>

Default: 15

Spatial radius

[number] <put parameter description here>

Default: 5

Minimum Region Size

[number] <put parameter description here>

Default: 0

Size of tiles in pixel (X-axis)

[number] <put parameter description here>

Default: 500

Size of tiles in pixel (Y-axis)

[number] <put parameter description here>

Default: 500

Directory where to write temporary files

[file] Optional.

<put parameter description here>

Temporary files cleaning

[boolean] <put parameter description here>

Default: True

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Outputs

Output Image

[raster] <put output description here>

Console usage

processing.runalg(’otb:exactlargescalemeanshiftsegmentationstep2’, -in, -inpos, -ranger, -spatialr, -minsize, -tilesizex, -tilesizey, -tmpdir, -cleanup, -out)

See also

Exact Large-Scale Mean-Shift segmentation, step 3 (optional)

Description

<put algortithm description here>

Parameters

Input image

[raster] <put parameter description here>

Segmented image

[raster] <put parameter description here>

Minimum Region Size

[number] <put parameter description here>

Default: 50

Size of tiles in pixel (X-axis)

[number] <put parameter description here>

Default: 500

Size of tiles in pixel (Y-axis)

[number] <put parameter description here>

Default: 500

Outputs

Output Image

[raster] <put output description here>

Console usage

processing.runalg(’otb:exactlargescalemeanshiftsegmentationstep3optional’, -in, -inseg, -minsize, -tilesizex, -tilesizey, -out)

See also

Exact Large-Scale Mean-Shift segmentation, step 4

Description

<put algortithm description here>

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Parameters

Input Image

[raster] <put parameter description here>

Segmented image

[raster] <put parameter description here>

Size of tiles in pixel (X-axis)

[number] <put parameter description here>

Default: 500

Size of tiles in pixel (Y-axis)

[number] <put parameter description here>

Default: 500

Outputs

Output GIS vector file

[vector] <put output description here>

Console usage

processing.runalg(’otb:exactlargescalemeanshiftsegmentationstep4’, -in, -inseg, -tilesizex, -tilesizey, -out)

See also

Hoover compare segmentation

Description

<put algortithm description here>

Parameters

Input ground truth

[raster] <put parameter description here>

Input machine segmentation

[raster] <put parameter description here>

Background label

[number] <put parameter description here>

Default: 0

Overlapping threshold

[number] <put parameter description here>

Default: 0.75

Correct detection score

[number] <put parameter description here>

Default: 0.0

Over-segmentation score

[number] <put parameter description here>

Default: 0.0

Under-segmentation score

[number] <put parameter description here>

Default: 0.0

Missed detection score

[number] <put parameter description here>

Default: 0.0

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Outputs

Colored ground truth output

[raster] <put output description here>

Colored machine segmentation output

[raster] <put output description here>

Console usage

processing .

runalg( ’otb:hoovercomparesegmentation’ , ingt, inms, bg, th, rc, rf, ra, rm, outgt, outms)

See also

Segmentation (cc)

Description

<put algortithm description here>

Parameters

Input Image

[raster] <put parameter description here>

Segmentation algorithm

[selection] <put parameter description here>

Options:

• 0 — cc

Default: 0

Condition

[string] <put parameter description here>

Default: None

Processing mode

[selection] <put parameter description here>

Options:

• 0 — vector

Default: 0

Writing mode for the output vector file

[selection] <put parameter description here>

Options:

• 0 — ulco

• 1 — ovw

• 2 — ulovw

• 3 — ulu

Default: 0

Mask Image

[raster] Optional.

<put parameter description here>

8-neighbor connectivity

[boolean] <put parameter description here>

Default: True

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Stitch polygons

[boolean] <put parameter description here>

Default: True

Minimum object size

[number] <put parameter description here>

Default: 1

Simplify polygons

[number] <put parameter description here>

Default: 0.1

Layer name

[string] <put parameter description here>

Default: layer

Geometry index field name

[string] <put parameter description here>

Default: DN

Tiles size

[number] <put parameter description here>

Default: 1024

Starting geometry index

[number] <put parameter description here>

Default: 1

OGR options for layer creation

[string] Optional.

<put parameter description here>

Default: None

Outputs

Output vector file

[vector] <put output description here>

Console usage

processing.runalg(’otb:segmentationcc’, -in, -filter, -filter.cc.expr, -mode, -mode.vector.outmode, -mode.vector.inmask, -mode.vector.neighbor, -mode.vector.stitch, -mode.vector.minsize, -mode.vector.simplify, -mode.vector.layername, -mode.vector.fieldname, -mode.vector.tilesize, -mode.vector.startlabel, -mode.vector.ogroptions, -mode.vector.out)

See also

Segmentation (edison)

Description

<put algortithm description here>

Parameters

Input Image

[raster] <put parameter description here>

Segmentation algorithm

[selection] <put parameter description here>

Options:

• 0 — edison

Default: 0

Spatial radius

[number] <put parameter description here>

Default: 5

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Range radius

[number] <put parameter description here>

Default: 15

Minimum region size

[number] <put parameter description here>

Default: 100

Scale factor

[number] <put parameter description here>

Default: 1

Processing mode

[selection] <put parameter description here>

Options:

• 0 — vector

Default: 0

Writing mode for the output vector file

[selection] <put parameter description here>

Options:

• 0 — ulco

• 1 — ovw

• 2 — ulovw

• 3 — ulu

Default: 0

Mask Image

[raster] Optional.

<put parameter description here>

8-neighbor connectivity

[boolean] <put parameter description here>

Default: True

Stitch polygons

[boolean] <put parameter description here>

Default: True

Minimum object size

[number] <put parameter description here>

Default: 1

Simplify polygons

[number] <put parameter description here>

Default: 0.1

Layer name

[string] <put parameter description here>

Default: layer

Geometry index field name

[string] <put parameter description here>

Default: DN

Tiles size

[number] <put parameter description here>

Default: 1024

Starting geometry index

[number] <put parameter description here>

Default: 1

OGR options for layer creation

[string] Optional.

<put parameter description here>

Default: None

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Outputs

Output vector file

[vector] <put output description here>

Console usage

processing.runalg(’otb:segmentationedison’, -in, -filter, -filter.edison.spatialr, -filter.edison.ranger, -filter.edison.minsize, -filter.edison.scale, -mode, -mode.vector.outmode, -mode.vector.inmask, -mode.vector.neighbor, -mode.vector.stitch, -mode.vector.minsize, -mode.vector.simplify, -mode.vector.layername, -mode.vector.fieldname, -mode.vector.tilesize, -mode.vector.startlabel, -mode.vector.ogroptions, -mode.vector.out)

See also

Segmentation (meanshift)

Description

<put algortithm description here>

Parameters

Input Image

[raster] <put parameter description here>

Segmentation algorithm

[selection] <put parameter description here>

Options:

• 0 — meanshift

Default: 0

Spatial radius

[number] <put parameter description here>

Default: 5

Range radius

[number] <put parameter description here>

Default: 15

Mode convergence threshold

[number] <put parameter description here>

Default: 0.1

Maximum number of iterations

[number] <put parameter description here>

Default: 100

Minimum region size

[number] <put parameter description here>

Default: 100

Processing mode

[selection] <put parameter description here>

Options:

• 0 — vector

Default: 0

Writing mode for the output vector file

[selection] <put parameter description here>

Options:

• 0 — ulco

• 1 — ovw

• 2 — ulovw

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• 3 — ulu

Default: 0

Mask Image

[raster] Optional.

<put parameter description here>

8-neighbor connectivity

[boolean] <put parameter description here>

Default: True

Stitch polygons

[boolean] <put parameter description here>

Default: True

Minimum object size

[number] <put parameter description here>

Default: 1

Simplify polygons

[number] <put parameter description here>

Default: 0.1

Layer name

[string] <put parameter description here>

Default: layer

Geometry index field name

[string] <put parameter description here>

Default: DN

Tiles size

[number] <put parameter description here>

Default: 1024

Starting geometry index

[number] <put parameter description here>

Default: 1

OGR options for layer creation

[string] Optional.

<put parameter description here>

Default: None

Outputs

Output vector file

[vector] <put output description here>

Console usage

processing.runalg(’otb:segmentationmeanshift’, -in, -filter, -filter.meanshift.spatialr, -filter.meanshift.ranger, -filter.meanshift.thres, -filter.meanshift.maxiter, -filter.meanshift.minsize, -mode, -mode.vector.outmode, -mode.vector.inmask, -mode.vector.neighbor, -mode.vector.stitch, -mode.vector.minsize, -mode.vector.simplify, -mode.vector.layername, -mode.vector.fieldname, -mode.vector.tilesize, -mode.vector.startlabel, -mode.vector.ogroptions, -mode.vector.out)

See also

Segmentation (mprofiles)

Description

<put algortithm description here>

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Parameters

Input Image

[raster] <put parameter description here>

Segmentation algorithm

[selection] <put parameter description here>

Options:

• 0 — mprofiles

Default: 0

Profile Size

[number] <put parameter description here>

Default: 5

Initial radius

[number] <put parameter description here>

Default: 1

Radius step.

[number] <put parameter description here>

Default: 1

Threshold of the final decision rule

[number] <put parameter description here>

Default: 1

Processing mode

[selection] <put parameter description here>

Options:

• 0 — vector

Default: 0

Writing mode for the output vector file

[selection] <put parameter description here>

Options:

• 0 — ulco

• 1 — ovw

• 2 — ulovw

• 3 — ulu

Default: 0

Mask Image

[raster] Optional.

<put parameter description here>

8-neighbor connectivity

[boolean] <put parameter description here>

Default: True

Stitch polygons

[boolean] <put parameter description here>

Default: True

Minimum object size

[number] <put parameter description here>

Default: 1

Simplify polygons

[number] <put parameter description here>

Default: 0.1

Layer name

[string] <put parameter description here>

Default: layer

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Geometry index field name

[string] <put parameter description here>

Default: DN

Tiles size

[number] <put parameter description here>

Default: 1024

Starting geometry index

[number] <put parameter description here>

Default: 1

OGR options for layer creation

[string] Optional.

<put parameter description here>

Default: None

Outputs

Output vector file

[vector] <put output description here>

Console usage

processing.runalg(’otb:segmentationmprofiles’, -in, -filter, -filter.mprofiles.size, -filter.mprofiles.start, -filter.mprofiles.step, -filter.mprofiles.sigma, -mode, -mode.vector.outmode, -mode.vector.inmask, -mode.vector.neighbor, -mode.vector.stitch, -mode.vector.minsize, -mode.vector.simplify, -mode.vector.layername, -mode.vector.fieldname, -mode.vector.tilesize, -mode.vector.startlabel, -mode.vector.ogroptions, -mode.vector.out)

See also

Segmentation (watershed)

Description

<put algortithm description here>

Parameters

Input Image

[raster] <put parameter description here>

Segmentation algorithm

[selection] <put parameter description here>

Options:

• 0 — watershed

Default: 0

Depth Threshold

[number] <put parameter description here>

Default: 0.01

Flood Level

[number] <put parameter description here>

Default: 0.1

Processing mode

[selection] <put parameter description here>

Options:

• 0 — vector

Default: 0

Writing mode for the output vector file

[selection] <put parameter description here>

Options:

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• 0 — ulco

• 1 — ovw

• 2 — ulovw

• 3 — ulu

Default: 0

Mask Image

[raster] Optional.

<put parameter description here>

8-neighbor connectivity

[boolean] <put parameter description here>

Default: True

Stitch polygons

[boolean] <put parameter description here>

Default: True

Minimum object size

[number] <put parameter description here>

Default: 1

Simplify polygons

[number] <put parameter description here>

Default: 0.1

Layer name

[string] <put parameter description here>

Default: layer

Geometry index field name

[string] <put parameter description here>

Default: DN

Tiles size

[number] <put parameter description here>

Default: 1024

Starting geometry index

[number] <put parameter description here>

Default: 1

OGR options for layer creation

[string] Optional.

<put parameter description here>

Default: None

Outputs

Output vector file

[vector] <put output description here>

Console usage

processing.runalg(’otb:segmentationwatershed’, -in, -filter, -filter.watershed.threshold, -filter.watershed.level, -mode, -mode.vector.outmode, -mode.vector.inmask, -mode.vector.neighbor, -mode.vector.stitch, -mode.vector.minsize, -mode.vector.simplify, -mode.vector.layername, -mode.vector.fieldname, -mode.vector.tilesize, -mode.vector.startlabel, -mode.vector.ogroptions, -mode.vector.out)

.

See also

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18.4.9 Stereo

Stereo Framework

Description

<put algortithm description here>

Parameters

Input images list

[multipleinput: rasters] <put parameter description here>

Couples list

[string] Optional.

<put parameter description here>

Default: None

Image channel used for the block matching

[number] <put parameter description here>

Default: 1

Default elevation

[number] <put parameter description here>

Default: 0

Output resolution

[number] <put parameter description here>

Default: 1

NoData value

[number] <put parameter description here>

Default: -32768

Method to fuse measures in each DSM cell

[selection] <put parameter description here>

Options:

• 0 — max

• 1 — min

• 2 — mean

• 3 — acc

Default: 0

Parameters estimation modes

[selection] <put parameter description here>

Options:

• 0 — fit

• 1 — user

Default: 0

Upper Left X

[number] <put parameter description here>

Default: 0.0

Upper Left Y

[number] <put parameter description here>

Default: 0.0

Size X

[number] <put parameter description here>

Default: 0

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Size Y

[number] <put parameter description here>

Default: 0

Pixel Size X

[number] <put parameter description here>

Default: 0.0

Pixel Size Y

[number] <put parameter description here>

Default: 0.0

Output Cartographic Map Projection

[selection] <put parameter description here>

Options:

• 0 — utm

• 1 — lambert2

• 2 — lambert93

• 3 — wgs

• 4 — epsg

Default: 3

Zone number

[number] <put parameter description here>

Default: 31

Northern Hemisphere

[boolean] <put parameter description here>

Default: True

EPSG Code

[number] <put parameter description here>

Default: 4326

Step of the deformation grid (in pixels)

[number] <put parameter description here>

Default: 16

Sub-sampling rate for epipolar grid inversion

[number] <put parameter description here>

Default: 10

Block-matching metric

[selection] <put parameter description here>

Options:

• 0 — ssdmean

• 1 — ssd

• 2 — ncc

• 3 — lp

Default: 0

p value

[number] <put parameter description here>

Default: 1

Radius of blocks for matching filter (in pixels)

[number] <put parameter description here>

Default: 2

Minimum altitude offset (in meters)

[number] <put parameter description here>

Default: -20

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Maximum altitude offset (in meters)

[number] <put parameter description here>

Default: 20

Use bijection consistency in block matching strategy

[boolean] <put parameter description here>

Default: True

Use median disparities filtering

[boolean] <put parameter description here>

Default: True

Correlation metric threshold

[number] <put parameter description here>

Default: 0.6

Input left mask

[raster] Optional.

<put parameter description here>

Input right mask

[raster] Optional.

<put parameter description here>

Discard pixels with low local variance

[number] <put parameter description here>

Default: 50

Available RAM (Mb)

[number] <put parameter description here>

Default: 128

Outputs

Output DSM

[raster] <put output description here>

Console usage

processing .

runalg( ’otb:stereoframework’ , input .

il, input .

co, input .

channel, elev .

default, output .

res, output .

nodata, output .

fusionmethod, output .

mode, output .

mode .

user .

ulx, output .

mode .

user .

uly, output .

mode .

user .

sizex, output .

mode .

user .

sizey, output .

mode .

user .

spacingx, output .

mode .

user .

spacingy, map , map .

utm .

zone, map .

utm .

northhem, map .

epsg .

code, stereorect .

fwdgridstep, stereorect .

invgridssrate, bm .

metric, bm .

metric .

lp .

p, bm .

radius, bm .

minhoffset, bm .

maxhoffset, postproc .

bij, postproc .

med, postproc .

metrict, mask .

left, mask .

right, mask .

variancet, ram, output .

out)

.

See also

18.4.10 Vector

Concatenate

Description

<put algortithm description here>

Parameters

Input VectorDatas to concatenate

[multipleinput: any vectors] <put parameter description here>

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Outputs

Concatenated VectorData

[vector] <put output description here>

Console usage

processing .

runalg( ’otb:concatenate’ , vd, out)

.

See also

18.5 QGIS algorithm provider

.

QGIS algortihm provider implements various analysis and geoprocessing operations using mostly only QGIS API.

So almost all algorthms from this provider will work “out of the box” without any additional configuration.

This provider incorporates fTools functionality, some algorithms from mmQGIS plugin and also adds its own algorithms.

18.5.1 Database

Import into PostGIS

Description

<put algortithm description here>

Parameters

Layer to import

[vector: any] <put parameter description here>

Database (connection name)

[selection] <put parameter description here>

Options:

• 0 — local

Default: 0

Schema (schema name)

[string] <put parameter description here>

Default: public

Table to import to (leave blank to use layer name)

[string] <put parameter description here>

Default: (not set)

Primary key field

[tablefield: any] Optional.

<put parameter description here>

Geometry column

[string] <put parameter description here>

Default: geom

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Overwrite

[boolean] <put parameter description here>

Default: True

Create spatial index

[boolean] <put parameter description here>

Default: True

Convert field names to lowercase

[boolean] <put parameter description here>

Default: True

Drop length constraints on character fields

[boolean] <put parameter description here>

Default: False

Outputs

Console usage

processing .

runalg( ’qgis:importintopostgis’ , input , database, schema, tablename, primary_key, geometry_column, overwrite, createindex, lowercase_names, drop_string_length)

See also

PostGIS execute SQL

Description

<put algortithm description here>

Parameters

Database

[string] <put parameter description here>

Default: (not set)

SQL query

[string] <put parameter description here>

Default: (not set)

Outputs

Console usage

processing .

runalg( ’qgis:postgisexecutesql’ , database, sql)

.

See also

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18.5.2 Raster general

Set style for raster layer

Description

<put algortithm description here>

Parameters

Raster layer

[raster] <put parameter description here>

Style file

[file] <put parameter description here>

Outputs

Styled layer

[raster] <put output description here>

Console usage

processing .

runalg( ’qgis:setstyleforrasterlayer’ , input , style)

.

See also

18.5.3 Raster

Hypsometric curves

Description

Calculate hypsometric curves for features of polygon layer and save them as CSV file for further processing.

Parameters

DEM to analyze

[raster] DEM to use for calculating altitudes.

Boundary layer

[vector: polygon] Polygonal vector layer with boundaries of areas used to calculate hypsometric curves.

Step

[number] Distanse between curves.

Default: 100.0

Use % of area instead of absolute value

[boolean] Write area percentage to “Area” field of the

CSV file instead of absolute area value.

Default: False

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Outputs

Output directory

[directory] Directory where output will be saved. For each feature from input vector layer CSV file with area and altitude values will be created.

File name consists of prefix hystogram_ followed by layer name and feature ID.

Console usage

processing .

runalg( ’qgis:hypsometriccurves’ , input_dem, boundary_layer, step, use_percentage, output_directory)

See also

Raster layer statistics

Description

Calculates basic statistics of the raster layer.

Parameters

Input layer

[raster] Raster to analyze.

Outputs

Statistics

[html] Analysis results in HTML format.

Minimum value

[number] Minimum cell value.

Maximum value

[number] Maximum cell value.

Sum

[number] Sum of all cells values.

Mean value

[number] Mean cell value.

valid cells count

[number] Number of cell with data.

No-data cells count

[number] Number of NODATA cells.

Standard deviation

[number] Standard deviation of cells values.

Console usage

processing .

runalg( ’qgis:rasterlayerstatistics’ , input , output_html_file)

See also

Zonal Statistics

Description

Calculates some statistics values for pixels of input raster inside certain zones, defined as polygon layer.

Following values calculated for each zone:

• minimum

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• maximum

• sum

• count

• mean

• standard deviation

• number of unique values

• range

• variance

Parameters

Raster layer

[raster] Raster to analyze.

Raster band

[number] Number of raster band to analyze.

Default: 1

Vector layer containing zones

[vector: polygon] Layer with zones boundaries.

Output column prefix

[string] Prefix for output fields.

Default: _

Load whole raster in memory

[boolean] Determines if raster band will be loaded in memory (True) or readed by chunks (False). Useful only when disk IO or raster scanning inefficiencies are your limiting factor.

Default: True

Outputs

Output layer

[vector] The resulting layer. Basically this is same layer as zones layer with new columns containing statistics added.

Console usage

processing .

runalg( ’qgis:zonalstatistics’ , input_raster, raster_band, input_vector, column_prefix, global_extent, output_layer)

.

See also

18.5.4 Table

Frequency analysis

Description

<put algortithm description here>

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Parameters input

[vector: any] <put parameter description here>

fields

[string] <put parameter description here>

Default: (not set)

Outputs output

[table] <put output description here>

Console usage

processing .

runalg( ’qgis:frequencyanalysis’ , input , fields, output)

.

See also

18.5.5 Vector analysis

Count points in polygon

Description

Counts the number of points present in each feature of a polygon layer.

Parameters

Polygons

[vector: polygon] Polygons layer.

Points

[vector: point] Points layer.

Count field name

[string] The name of the attribute table column containing the points number.

Default: NUMPOINTS

Outputs

Result

[vector] Resulting layer with the attribute table containing the new column of the points count.

Console usage

processing .

runalg( ’qgis:countpointsinpolygon’ , polygons, points, field, output)

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See also

Count points in polygon (weighted)

Description

Counts the number of points in each feature of a polygon layer and calculates the mean of the selected field for each feature of the polygon layer. These values will be added to the attribute table of the resulting polygon layer.

Parameters

Polygons

[vector: polygon] Polygons layer.

Points

[vector: point] Points layer.

Weight field

[tablefield: any] Weight field of the points attribute table.

Count field name

[string] Name of the column for the new weighted field.

Default: NUMPOINTS

Outputs

Result

[vector] The resulting polygons layer.

Console usage

processing .

runalg( ’qgis:countpointsinpolygonweighted’ , polygons, points, weight, field, output)

See also

Count unique points in polygon

Description

Counts the number of unique values of a points in a polygons layer. Creates a new polygons layer with an extra column in the attribute table containing the count of unique values for each feature.

Parameters

Polygons

[vector: polygon] Polygons layer.

Points

[vector: point] Points layer.

Class field

[tablefield: any] Points layer column name of the unique value chosen.

Count field name

[string] Column name containing the count of unique values in the resulting polygons layer.

Default: NUMPOINTS

Outputs

Result

[vector] The resulting polygons layer.

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Console usage

processing .

runalg( ’qgis:countuniquepointsinpolygon’ , polygons, points, classfield, field, output)

See also

Distance matrix

Description

<put algortithm description here>

Parameters

Input point layer

[vector: point] <put parameter description here>

Input unique ID field

[tablefield: any] <put parameter description here>

Target point layer

[vector: point] <put parameter description here>

Target unique ID field

[tablefield: any] <put parameter description here>

Output matrix type

[selection] <put parameter description here>

Options:

• 0 — Linear (N*k x 3) distance matrix

• 1 — Standard (N x T) distance matrix

• 2 — Summary distance matrix (mean, std. dev., min, max)

Default: 0

Use only the nearest (k) target points

[number] <put parameter description here>

Default: 0

Outputs

Distance matrix

[table] <put output description here>

Console usage

processing .

runalg( ’qgis:distancematrix’ , input_layer, input_field, target_layer, target_field, matrix_type, nearest_points, distance_matrix)

See also

Distance to nearest hub

Description

<put algortithm description here>

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Parameters

Source points layer

[vector: any] <put parameter description here>

Destination hubs layer

[vector: any] <put parameter description here>

Hub layer name attribute

[tablefield: any] <put parameter description here>

Output shape type

[selection] <put parameter description here>

Options:

• 0 — Point

• 1 — Line to hub

Default: 0

Measurement unit

[selection] <put parameter description here>

Options:

• 0 — Meters

• 1 — Feet

• 2 — Miles

• 3 — Kilometers

• 4 — Layer units

Default: 0

Outputs

Output

[vector] <put output description here>

Console usage

processing .

runalg( ’qgis:distancetonearesthub’ , points, hubs, field, geometry, unit, output)

See also

Generate points (pixel centroids) along line

Description

<put algortithm description here>

Parameters

Raster layer

[raster] <put parameter description here>

Vector layer

[vector: line] <put parameter description here>

Outputs

Output layer

[vector] <put output description here>

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Console usage

processing .

runalg( ’qgis:generatepointspixelcentroidsalongline’ , input_raster, input_vector, output_layer)

See also

Generate points (pixel centroids) inside polygons

Description

<put algortithm description here>

Parameters

Raster layer

[raster] <put parameter description here>

Vector layer

[vector: polygon] <put parameter description here>

Outputs

Output layer

[vector] <put output description here>

Console usage

processing .

runalg( ’qgis:generatepointspixelcentroidsinsidepolygons’ , input_raster, input_vector, output_layer)

See also

Hub lines

Description

Creates hub and spoke diagrams with lines drawn from points on the Spoke Point layer to matching points in the Hub Point layer. Determination of which hub goes with each point is based on a match between the Hub

ID field on the hub points and the Spoke ID field on the spoke points.

Parameters

Hub point layer

[vector: any] <put parameter description here>

Hub ID field

[tablefield: any] <put parameter description here>

Spoke point layer

[vector: any] <put parameter description here>

Spoke ID field

[tablefield: any] <put parameter description here>

Outputs

Output

[vector] The resulting layer.

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Console usage

processing .

runalg( ’qgis:hublines’ , hubs, hub_field, spokes, spoke_field, output)

See also

Mean coordinate(s)

Description

Calculates the mean of the coordinates of a layer starting from a field of the attribute table.

Parameters

Input layer

[vector: any] <put parameter description here>

Weight field

[tablefield: numeric] Optional.

Field to use if you want to perform a weighted mean.

Unique ID field

[tablefield: numeric] Optional.

Unique field on which the calculation of the mean will be made.

Outputs

Result

[vector] The resulting points layer.

Console usage

processing .

runalg( ’qgis:meancoordinates’ , points, weight, uid, output)

See also

Nearest neighbour analysis

Description

<put algortithm description here>

Parameters

Points

[vector: point] <put parameter description here>

Outputs

Result

[html] <put output description here>

Observed mean distance

[number] <put output description here>

Expected mean distance

[number] <put output description here>

Nearest neighbour index

[number] <put output description here>

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Number of points

[number] <put output description here>

Z-Score

[number] <put output description here>

Console usage

processing .

runalg( ’qgis:nearestneighbouranalysis’ , points, output)

See also

Sum line lengths

Description

<put algortithm description here>

Parameters

Lines

[vector: line] <put parameter description here>

Polygons

[vector: polygon] <put parameter description here>

Lines length field name

[string] <put parameter description here>

Default: LENGTH

Lines count field name

[string] <put parameter description here>

Default: COUNT

Outputs

Result

[vector] <put output description here>

Console usage

processing .

runalg( ’qgis:sumlinelengths’ , lines, polygons, len_field, count_field, output)

.

See also

18.5.6 Vector creation

Create grid

Description

Creates a grid.

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Parameters

Grid type

[selection] Grid type.

Options:

• 0 — Rectangle (line)

• 1 — Rectangle (polygon)

• 2 — Diamond (polygon)

• 3 — Hexagon (polygon)

Default: 0

Width

[number] Horizontal extent of the grid.

Default: 360.0

Height

[number] Vertical extent of the grid.

Default: 180.0

Horizontal spacing

[number] X-axes spacing between the lines.

Default: 10.0

Vertical spacing

[number] Y-axes spacing between the lines.

Default: 10.0

Center X

[number] X-coordinate of the grid center.

Default: 0.0

Center Y

[number] Y-coordinate of the grid center.

Default: 0.0

Output CRS

[crs] Coordinate reference system for grid.

Default: EPSG:4326

Outputs

Output

[vector] The resulting grid layer (lines or polygons).

Console usage

processing .

runalg( ’qgis:creategrid’ , type , width, height, hspacing, vspacing, centerx, centery, crs, output)

See also

Points layer from table

Description

Creates points layer from geometryless table with columns that contain point coordinates.

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Parameters

Input layer

[table] Input table

X field

[tablefield: any] Table column containing the X coordinate.

Y field

[tablefield: any] Table column containing the Y coordinate.

Target CRS

[crs] Coordinate reference system to use for layer.

Default: EPSG:4326

Outputs

Output layer

[vector] The resulting layer.

Console usage

processing .

runalg( ’qgis:pointslayerfromtable’ , input , xfield, yfield, target_crs, output)

See also

Points to path

Description

<put algortithm description here>

Parameters

Input point layer

[vector: point] <put parameter description here>

Group field

[tablefield: any] <put parameter description here>

Order field

[tablefield: any] <put parameter description here>

Date format (if order field is DateTime)

[string] Optional.

<put parameter description here>

Default: (not set)

Outputs

Paths

[vector] <put output description here>

Directory

[directory] <put output description here>

Console usage

processing .

runalg( ’qgis:pointstopath’ , vector, group_field, order_field, date_format, output_lines, output_text)

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See also

Random points along line

Description

<put algortithm description here>

Parameters

Input layer

[vector: line] <put parameter description here>

Number of points

[number] <put parameter description here>

Default: 1

Minimum distance

[number] <put parameter description here>

Default: 0.0

Outputs

Random points

[vector] <put output description here>

Console usage

processing .

runalg( ’qgis:randompointsalongline’ , vector, point_number, min_distance, output)

See also

Random points in extent

Description

<put algortithm description here>

Parameters

Input extent

[extent] <put parameter description here>

Default: 0,1,0,1

Points number

[number] <put parameter description here>

Default: 1

Minimum distance

[number] <put parameter description here>

Default: 0.0

Outputs

Random points

[vector] <put output description here>

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Console usage

processing .

runalg( ’qgis:randompointsinextent’ , extent, point_number, min_distance, output)

See also

Random points in layer bounds

Description

<put algortithm description here>

Parameters

Input layer

[vector: polygon] <put parameter description here>

Points number

[number] <put parameter description here>

Default: 1

Minimum distance

[number] <put parameter description here>

Default: 0.0

Outputs

Random points

[vector] <put output description here>

Console usage

processing .

runalg( ’qgis:randompointsinlayerbounds’ , vector, point_number, min_distance, output)

See also

Random points inside polygons (fixed)

Description

<put algortithm description here>

Parameters

Input layer

[vector: polygon] <put parameter description here>

Sampling strategy

[selection] <put parameter description here>

Options:

• 0 — Points count

• 1 — Points density

Default: 0

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Number or density of points

[number] <put parameter description here>

Default: 1.0

Minimum distance

[number] <put parameter description here>

Default: 0.0

Outputs

Random points

[vector] <put output description here>

Console usage

processing .

runalg( ’qgis:randompointsinsidepolygonsfixed’ , vector, strategy, value, min_distance, output)

See also

Random points inside polygons (variable)

Description

<put algortithm description here>

Parameters

Input layer

[vector: polygon] <put parameter description here>

Sampling strategy

[selection] <put parameter description here>

Options:

• 0 — Points count

• 1 — Points density

Default: 0

Number field

[tablefield: numeric] <put parameter description here>

Minimum distance

[number] <put parameter description here>

Default: 0.0

Outputs

Random points

[vector] <put output description here>

Console usage

processing .

runalg( ’qgis:randompointsinsidepolygonsvariable’ , vector, strategy, field, min_distance, output)

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See also

Regular points

Description

<put algortithm description here>

Parameters

Input extent

[extent] <put parameter description here>

Default: 0,1,0,1

Point spacing/count

[number] <put parameter description here>

Default: 0.0001

Initial inset from corner (LH side)

[number] <put parameter description here>

Default: 0.0

Apply random offset to point spacing

[boolean] <put parameter description here>

Default: False

Use point spacing

[boolean] <put parameter description here>

Default: True

Outputs

Regular points

[vector] <put output description here>

Console usage

processing .

runalg( ’qgis:regularpoints’ , extent, spacing, inset, randomize, is_spacing, output)

See also

Vector grid

Description

<put algortithm description here>

Parameters

Grid extent

[extent] <put parameter description here>

Default: 0,1,0,1

X spacing

[number] <put parameter description here>

Default: 0.0001

Y spacing

[number] <put parameter description here>

Default: 0.0001

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Grid type

[selection] <put parameter description here>

Options:

• 0 — Output grid as polygons

• 1 — Output grid as lines

Default: 0

Outputs

Grid

[vector] <put output description here>

Console usage

processing .

runalg( ’qgis:vectorgrid’ , extent, step_x, step_y, type , output)

.

See also

18.5.7 Vector general

Delete duplicate geometries

Description

<put algortithm description here>

Parameters

Input layer

[vector: any] <put parameter description here>

Outputs

Output

[vector] <put output description here>

Console usage

processing .

runalg( ’qgis:deleteduplicategeometries’ , input , output)

See also

Join atributes by location

Description

<put algortithm description here>

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Parameters

Target vector layer

[vector: any] <put parameter description here>

Join vector layer

[vector: any] <put parameter description here>

Attribute summary

[selection] <put parameter description here>

Options:

• 0 — Take attributes of the first located feature

• 1 — Take summary of intersecting features

Default: 0

Statistics for summary (comma separated)

[string] <put parameter description here>

Default: sum,mean,min,max,median

Output table

[selection] <put parameter description here>

Options:

• 0 — Only keep matching records

• 1 — Keep all records (including non-matching target records)

Default: 0

Outputs

Output layer

[vector] <put output description here>

Console usage

processing .

runalg( ’qgis:joinatributesbylocation’ , target, join, summary, stats, keep, output)

See also

Join attributes table

Description

<put algortithm description here>

Parameters

Input layer

[vector: any] <put parameter description here>

Input layer 2

[table] <put parameter description here>

Table field

[tablefield: any] <put parameter description here>

Table field 2

[tablefield: any] <put parameter description here>

Outputs

Output layer

[vector] <put output description here>

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Console usage

processing .

runalg( ’qgis:joinattributestable’ , input_layer, input_layer_2, table_field, table_field_2, output_layer)

See also

Merge vector layers

Description

<put algortithm description here>

Parameters

Input layer 1

[vector: any] <put parameter description here>

Input layer 2

[vector: any] <put parameter description here>

Outputs

Output

[vector] <put output description here>

Console usage

processing .

runalg( ’qgis:mergevectorlayers’ , layer1, layer2, output)

See also

Polygon from layer extent

Description

<put algortithm description here>

Parameters

Input layer

[vector: any] <put parameter description here>

Calculate extent for each feature separately

[boolean] <put parameter description here>

Default: False

Outputs

Output layer

[vector] <put output description here>

Console usage

processing .

runalg( ’qgis:polygonfromlayerextent’ , input_layer, by_feature, output)

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See also

Reproject layer

Description

Reprojects a vector layer in a different CRS.

Parameters

Input layer

[vector: any] Layer to reproject.

Target CRS

[crs] Destination coordinate reference system.

Default: EPSG:4326

Outputs

Reprojected layer

[vector] The resulting layer.

Console usage

processing .

runalg( ’qgis:reprojectlayer’ , input , target_crs, output)

See also

Save selected features

Description

Saves the selected features as a new layer.

Parameters

Input layer

[vector: any] Layer to process.

Outputs

Output layer with selected features

[vector] The resulting layer.

Console usage

processing .

runalg( ’qgis:saveselectedfeatures’ , input_layer, output_layer)

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See also

Set style for vector layer

Description

<put algortithm description here>

Parameters

Vector layer

[vector: any] <put parameter description here>

Style file

[file] <put parameter description here>

Outputs

Styled layer

[vector] <put output description here>

Console usage

processing .

runalg( ’qgis:setstyleforvectorlayer’ , input , style)

See also

Snap points to grid

Description

<put algortithm description here>

Parameters

Input Layer

[vector: any] <put parameter description here>

Horizontal spacing

[number] <put parameter description here>

Default: 0.1

Vertical spacing

[number] <put parameter description here>

Default: 0.1

Outputs

Output

[vector] <put output description here>

Console usage

processing .

runalg( ’qgis:snappointstogrid’ , input , hspacing, vspacing, output)

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See also

Split vector layer

Description

<put algortithm description here>

Parameters

Input layer

[vector: any] <put parameter description here>

Unique ID field

[tablefield: any] <put parameter description here>

Outputs

Output directory

[directory] <put output description here>

Console usage

processing .

runalg( ’qgis:splitvectorlayer’ , input , field, output)

.

See also

18.5.8 Vector geometry

Concave hull

Description

<put algortithm description here>

Parameters

Input point layer

[vector: point] <put parameter description here>

Threshold (0-1, where 1 is equivalent with Convex Hull)

[number] <put parameter description here>

Default: 0.3

Allow holes

[boolean] <put parameter description here>

Default: True

Split multipart geometry into singleparts geometries

[boolean] <put parameter description here>

Default: False

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Outputs

Concave hull

[vector] <put output description here>

Console usage

processing .

runalg( ’qgis:concavehull’ , input , alpha, holes, no_multigeometry, output)

See also

Convert geometry type

Description

Converts a geometry type to another one.

Parameters

Input layer

[vector: any] Layer in input.

New geometry type

[selection] Type of conversion to perform.

Options:

• 0 — Centroids

• 1 — Nodes

• 2 — Linestrings

• 3 — Multilinestrings

• 4 — Polygons

Default: 0

Outputs

Output

[vector] The resulting layer.

Console usage

processing .

runalg( ’qgis:convertgeometrytype’ , input , type , output)

See also

Convex hull

Description

<put algortithm description here>

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Parameters

Input layer

[vector: any] <put parameter description here>

Field (optional, only used if creating convex hulls by classes)

[tablefield: any]

Optional.

<put parameter description here>

Method

[selection] <put parameter description here>

Options:

• 0 — Create single minimum convex hull

• 1 — Create convex hulls based on field

Default: 0

Outputs

Convex hull

[vector] <put output description here>

Console usage

processing .

runalg( ’qgis:convexhull’ , input , field, method, output)

See also

Create points along lines

Description

<put algortithm description here>

Parameters lines

[vector: any] <put parameter description here>

distance

[number] <put parameter description here>

Default: 1

startpoint

[number] <put parameter description here>

Default: 0

endpoint

[number] <put parameter description here>

Default: 0

Outputs output

[vector] <put output description here>

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Console usage

processing .

runalg( ’qgis:createpointsalonglines’ , lines, distance, startpoint, endpoint, output)

See also

Delaunay triangulation

Description

<put algortithm description here>

Parameters

Input layer

[vector: point] <put parameter description here>

Outputs

Delaunay triangulation

[vector] <put output description here>

Console usage

processing .

runalg( ’qgis:delaunaytriangulation’ , input , output)

See also

Densify geometries given an interval

Description

<put algortithm description here>

Parameters

Input layer

[vector: polygon, line] <put parameter description here>

Interval between Vertices to add

[number] <put parameter description here>

Default: 1.0

Outputs

Densified layer

[vector] <put output description here>

Console usage

processing .

runalg( ’qgis:densifygeometriesgivenaninterval’ , input , interval, output)

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See also

Densify geometries

Description

<put algortithm description here>

Parameters

Input layer

[vector: polygon, line] <put parameter description here>

Vertices to add

[number] <put parameter description here>

Default: 1

Outputs

Densified layer

[vector] <put output description here>

Console usage

processing .

runalg( ’qgis:densifygeometries’ , input , vertices, output)

See also

Dissolve

Description

<put algortithm description here>

Parameters

Input layer

[vector: polygon, line] <put parameter description here>

Dissolve all (do not use field)

[boolean] <put parameter description here>

Default: True

Unique ID field

[tablefield: any] Optional.

<put parameter description here>

Outputs

Dissolved

[vector] <put output description here>

Console usage

processing .

runalg( ’qgis:dissolve’ , input , dissolve_all, field, output)

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See also

Eliminate sliver polygons

Description

<put algortithm description here>

Parameters

Input layer

[vector: polygon] <put parameter description here>

Use current selection in input layer (works only if called from toolbox)

[boolean]

<put parameter description here>

Default: False

Selection attribute

[tablefield: any] <put parameter description here>

Comparison

[selection] <put parameter description here>

Options:

• 0 — ==

• 1 — !=

• 2 — >

• 3 — >=

• 4 — <

• 5 — <=

• 6 — begins with

• 7 — contains

Default: 0

Value

[string] <put parameter description here>

Default: 0

Merge selection with the neighbouring polygon with the

[selection] <put parameter description here>

Options:

• 0 — Largest area

• 1 — Smallest Area

• 2 — Largest common boundary

Default: 0

Outputs

Cleaned layer

[vector] <put output description here>

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Console usage

processing .

runalg( ’qgis:eliminatesliverpolygons’ , input , keepselection, attribute, comparison, comparisonvalue, mode, output)

See also

Explode lines

Description

<put algortithm description here>

Parameters

Input layer

[vector: line] <put parameter description here>

Outputs

Output layer

[vector] <put output description here>

Console usage

processing .

runalg( ’qgis:explodelines’ , input , output)

See also

Extract nodes

Description

<put algortithm description here>

Parameters

Input layer

[vector: polygon, line] <put parameter description here>

Outputs

Output layer

[vector] <put output description here>

Console usage

processing .

runalg( ’qgis:extractnodes’ , input , output)

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See also

Fill holes

Description

<put algortithm description here>

Parameters

Polygons

[vector: any] <put parameter description here>

Max area

[number] <put parameter description here>

Default: 100000

Outputs

Results

[vector] <put output description here>

Console usage

processing .

runalg( ’qgis:fillholes’ , polygons, max_area, results)

See also

Fixed distance buffer

Description

<put algortithm description here>

Parameters

Input layer

[vector: any] <put parameter description here>

Distance

[number] <put parameter description here>

Default: 10.0

Segments

[number] <put parameter description here>

Default: 5

Dissolve result

[boolean] <put parameter description here>

Default: False

Outputs

Buffer

[vector] <put output description here>

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Console usage

processing .

runalg( ’qgis:fixeddistancebuffer’ , input , distance, segments, dissolve, output)

See also

Keep n biggest parts

Description

<put algortithm description here>

Parameters

Polygons

[vector: polygon] <put parameter description here>

To keep

[number] <put parameter description here>

Default: 1

Outputs

Results

[vector] <put output description here>

Console usage

processing .

runalg( ’qgis:keepnbiggestparts’ , polygons, to_keep, results)

See also

Lines to polygons

Description

<put algortithm description here>

Parameters

Input layer

[vector: line] <put parameter description here>

Outputs

Output layer

[vector] <put output description here>

Console usage

processing .

runalg( ’qgis:linestopolygons’ , input , output)

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See also

Multipart to singleparts

Description

<put algortithm description here>

Parameters

Input layer

[vector: any] <put parameter description here>

Outputs

Output layer

[vector] <put output description here>

Console usage

processing .

runalg( ’qgis:multiparttosingleparts’ , input , output)

See also

Points displacement

Description

Moves overlapped points at small distance, that they all become visible. The result is very similar to the output of the “Point displacement” renderer but it is permanent.

Parameters

Input layer

[vector: point] Layer with overlapped points.

Displacement distance

[number] Desired displacement distance NOTE: displacement distance should be in same units as layer.

Default: 0.00015

Horizontal distribution for two point case

[boolean] Controls distrobution direction in case of two overlapped points. If True points wwill be distributed horizontally, otherwise they will be distributed vertically.

Default: True

Outputs

Output layer

[vector] The resulting layer with shifted overlapped points.

Console usage

processing .

runalg( ’qgis:pointsdisplacement’ , input_layer, distance, horizontal, output_layer)

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See also

Polygon centroids

Description

<put algortithm description here>

Parameters

Input layer

[vector: polygon] <put parameter description here>

Outputs

Output layer

[vector] <put output description here>

Console usage

processing .

runalg( ’qgis:polygoncentroids’ , input_layer, output_layer)

See also

Polygonize

Description

<put algortithm description here>

Parameters

Input layer

[vector: line] <put parameter description here>

Keep table structure of line layer

[boolean] <put parameter description here>

Default: False

Create geometry columns

[boolean] <put parameter description here>

Default: True

Outputs

Output layer

[vector] <put output description here>

Console usage

processing .

runalg( ’qgis:polygonize’ , input , fields, geometry, output)

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See also

Polygons to lines

Description

<put algortithm description here>

Parameters

Input layer

[vector: polygon] <put parameter description here>

Outputs

Output layer

[vector] <put output description here>

Console usage

processing .

runalg( ’qgis:polygonstolines’ , input , output)

See also

Simplify geometries

Description

<put algortithm description here>

Parameters

Input layer

[vector: polygon, line] <put parameter description here>

Tolerance

[number] <put parameter description here>

Default: 1.0

Outputs

Simplified layer

[vector] <put output description here>

Console usage

processing .

runalg( ’qgis:simplifygeometries’ , input , tolerance, output)

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See also

Singleparts to multipart

Description

<put algortithm description here>

Parameters

Input layer

[vector: any] <put parameter description here>

Unique ID field

[tablefield: any] <put parameter description here>

Outputs

Output layer

[vector] <put output description here>

Console usage

processing .

runalg( ’qgis:singlepartstomultipart’ , input , field, output)

See also

Variable distance buffer

Description

<put algortithm description here>

Parameters

Input layer

[vector: any] <put parameter description here>

Distance field

[tablefield: any] <put parameter description here>

Segments

[number] <put parameter description here>

Default: 5

Dissolve result

[boolean] <put parameter description here>

Default: False

Outputs

Buffer

[vector] <put output description here>

Console usage

processing .

runalg( ’qgis:variabledistancebuffer’ , input , field, segments, dissolve, output)

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See also

Voronoi polygons

Description

<put algortithm description here>

Parameters

Input layer

[vector: point] <put parameter description here>

Buffer region

[number] <put parameter description here>

Default: 0.0

Outputs

Voronoi polygons

[vector] <put output description here>

Console usage

processing .

runalg( ’qgis:voronoipolygons’ , input , buffer , output)

.

See also

18.5.9 Vector overlay

Clip

Description

<put algortithm description here>

Parameters

Input layer

[vector: any] <put parameter description here>

Clip layer

[vector: any] <put parameter description here>

Outputs

Clipped

[vector] <put output description here>

Console usage

processing .

runalg( ’qgis:clip’ , input , overlay, output)

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Difference

Description

<put algortithm description here>

Parameters

Input layer

[vector: any] <put parameter description here>

Difference layer

[vector: any] <put parameter description here>

Outputs

Difference

[vector] <put output description here>

Console usage

processing .

runalg( ’qgis:difference’ , input , overlay, output)

See also

Intersection

Description

<put algortithm description here>

Parameters

Input layer

[vector: any] <put parameter description here>

Intersect layer

[vector: any] <put parameter description here>

Outputs

Intersection

[vector] <put output description here>

Console usage

processing .

runalg( ’qgis:intersection’ , input , input2, output)

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See also

Line intersections

Description

<put algortithm description here>

Parameters

Input layer

[vector: line] <put parameter description here>

Intersect layer

[vector: line] <put parameter description here>

Input unique ID field

[tablefield: any] <put parameter description here>

Intersect unique ID field

[tablefield: any] <put parameter description here>

Outputs

Output layer

[vector] <put output description here>

Console usage

processing .

runalg( ’qgis:lineintersections’ , input_a, input_b, field_a, field_b, output)

See also

Symetrical difference

Description

<put algortithm description here>

Parameters

Input layer

[vector: any] <put parameter description here>

Difference layer

[vector: any] <put parameter description here>

Outputs

Symetrical difference

[vector] <put output description here>

Console usage

processing .

runalg( ’qgis:symetricaldifference’ , input , overlay, output)

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See also

Union

Description

<put algortithm description here>

Parameters

Input layer

[vector: any] <put parameter description here>

Input layer 2

[vector: any] <put parameter description here>

Outputs

Union

[vector] <put output description here>

Console usage

processing .

runalg( ’qgis:union’ , input , input2, output)

.

See also

18.5.10 Vector selection

Extract by attribute

Description

<put algortithm description here>

Parameters

Input Layer

[vector: any] <put parameter description here>

Selection attribute

[tablefield: any] <put parameter description here>

Operator

[selection] <put parameter description here>

Options:

• 0 — =

• 1 — !=

• 2 — >

• 3 — >=

• 4 — <

• 5 — <=

• 6 — begins with

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• 7 — contains

Default: 0

Value

[string] <put parameter description here>

Default: (not set)

Outputs

Output

[vector] <put output description here>

Console usage

processing .

runalg( ’qgis:extractbyattribute’ , input , field, operator, value, output)

See also

Extract by location

Description

<put algortithm description here>

Parameters

Layer to select from

[vector: any] <put parameter description here>

Additional layer (intersection layer)

[vector: any] <put parameter description here>

Include input features that touch the selection features

[boolean] <put parameter description here>

Default: False

Include input features that overlap/cross the selection features

[boolean] <put parameter description here>

Default: False

Include input features completely within the selection features

[boolean] <put parameter description here>

Default: False

Outputs

Selection

[vector] <put output description here>

Console usage

processing .

runalg( ’qgis:extractbylocation’ , input , intersect, touches, overlaps, within, output)

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See also

Random extract

Description

<put algortithm description here>

Parameters

Input layer

[vector: any] <put parameter description here>

Method

[selection] <put parameter description here>

Options:

• 0 — Number of selected features

• 1 — Percentage of selected features

Default: 0

Number/percentage of selected features

[number] <put parameter description here>

Default: 10

Outputs

Selection

[vector] <put output description here>

Console usage

processing .

runalg( ’qgis:randomextract’ , input , method, number, output)

See also

Random extract within subsets

Description

<put algortithm description here>

Parameters

Input layer

[vector: any] <put parameter description here>

ID Field

[tablefield: any] <put parameter description here>

Method

[selection] <put parameter description here>

Options:

• 0 — Number of selected features

• 1 — Percentage of selected features

Default: 0

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Number/percentage of selected features

[number] <put parameter description here>

Default: 10

Outputs

Selection

[vector] <put output description here>

Console usage

processing .

runalg( ’qgis:randomextractwithinsubsets’ , input , field, method, number, output)

See also

Random selection

Description

<put algortithm description here>

Parameters

Input layer

[vector: any] <put parameter description here>

Method

[selection] <put parameter description here>

Options:

• 0 — Number of selected features

• 1 — Percentage of selected features

Default: 0

Number/percentage of selected features

[number] <put parameter description here>

Default: 10

Outputs

Selection

[vector] <put output description here>

Console usage

processing .

runalg( ’qgis:randomselection’ , input , method, number)

See also

Random selection within subsets

Description

<put algortithm description here>

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Parameters

Input layer

[vector: any] <put parameter description here>

ID Field

[tablefield: any] <put parameter description here>

Method

[selection] <put parameter description here>

Options:

• 0 — Number of selected features

• 1 — Percentage of selected features

Default: 0

Number/percentage of selected features

[number] <put parameter description here>

Default: 10

Outputs

Selection

[vector] <put output description here>

Console usage

processing .

runalg( ’qgis:randomselectionwithinsubsets’ , input , field, method, number)

See also

Select by attribute

Description

Selects and saves as new layer all features from input layer that satisfy condition.

NOTE

: algorithm is case-sensitive (“qgis” is different from “Qgis” and “QGIS”)

Parameters

Input Layer

[vector: any] Layer to process.

Selection attribute

[tablefield: any] Field on which perform the selection.

Operator

[selection] Comparison operator.

Options:

• 0 — =

• 1 — !=

• 2 — >

• 3 — >=

• 4 — <

• 5 — <=

• 6 — begins with

• 7 — contains

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Default: 0

Value

[string] Value to compare.

Default: (not set)

Outputs

Output

[vector] The resulting layer.

Console usage

processing .

runalg( ’qgis:selectbyattribute’ , input , field, operator, value, output)

See also

Select by expression

Description

<put algortithm description here>

Parameters

Input Layer

[vector: any] <put parameter description here>

Expression

[string] <put parameter description here>

Default: (not set)

Modify current selection by

[selection] <put parameter description here>

Options:

• 0 — creating new selection

• 1 — adding to current selection

• 2 — removing from current selection

Default: 0

Outputs

Output

[vector] <put output description here>

Console usage

processing .

runalg( ’qgis:selectbyexpression’ , layername, expression, method)

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Select by location

Description

<put algortithm description here>

Parameters

Layer to select from

[vector: any] <put parameter description here>

Additional layer (intersection layer)

[vector: any] <put parameter description here>

Include input features that touch the selection features

[boolean] <put parameter description here>

Default: False

Include input features that overlap/cross the selection features

[boolean] <put parameter description here>

Default: False

Include input features completely within the selection features

[boolean] <put parameter description here>

Default: False

Modify current selection by

[selection] <put parameter description here>

Options:

• 0 — creating new selection

• 1 — adding to current selection

• 2 — removing from current selection

Default: 0

Outputs

Selection

[vector] <put output description here>

Console usage

processing .

runalg( ’qgis:selectbylocation’ , input , intersect, touches, overlaps, within, method)

.

See also

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18.5.11 Vector table

Add autoincremental field

Description

<put algortithm description here>

Parameters

Input layer

[vector: any] <put parameter description here>

Outputs

Output layer

[vector] <put output description here>

Console usage

processing .

runalg( ’qgis:addautoincrementalfield’ , input , output)

See also

Add field to attributes table

Description

<put algortithm description here>

Parameters

Input layer

[vector: any] <put parameter description here>

Field name

[string] <put parameter description here>

Default: (not set)

Field type

[selection] <put parameter description here>

Options:

• 0 — Integer

• 1 — Float

• 2 — String

Default: 0

Field length

[number] <put parameter description here>

Default: 10

Field precision

[number] <put parameter description here>

Default: 0

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Outputs

Output layer

[vector] <put output description here>

Console usage

processing .

runalg( ’qgis:addfieldtoattributestable’ , input_layer, field_name, field_type, field_length, field_precision, output_layer)

See also

Advanced Python field calculator

Description

<put algorithm description here>

Parameters

Input layer

[vector: any] <put parameter description here>

Result field name

[string] <put parameter description here>

Default: NewField

Field type

[selection] <put parameter description here>

Options:

• 0 — Integer

• 1 — Float

• 2 — String

Default: 0

Field length

[number] <put parameter description here>

Default: 10

Field precision

[number] <put parameter description here>

Default: 0

Global expression

[string] Optional.

<put parameter description here>

Default: (not set)

Formula

[string] <put parameter description here>

Default: value =

Outputs

Output layer

[vector] <put output description here>

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Console usage

processing.runalg(’qgis:advancedpythonfieldcalculator’, input_layer, field_name, field_type, field_length, field_precision, global, formula, output_layer)

See also

Basic statistics for numeric fields

Description

<put algortithm description here>

Parameters

Input vector layer

[vector: any] <put parameter description here>

Field to calculate statistics on

[tablefield: numeric] <put parameter description here>

Outputs

Statistics for numeric field

[html] <put output description here>

Coefficient of Variation

[number] <put output description here>

Minimum value

[number] <put output description here>

Maximum value

[number] <put output description here>

Sum

[number] <put output description here>

Mean value

[number] <put output description here>

Count

[number] <put output description here>

Range

[number] <put output description here>

Median

[number] <put output description here>

Number of unique values

[number] <put output description here>

Standard deviation

[number] <put output description here>

Console usage

processing .

runalg( ’qgis:basicstatisticsfornumericfields’ , input_layer, field_name, output_html_file)

See also

Basic statistics for text fields

Description

<put algortithm description here>

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Parameters

Input vector layer

[vector: any] <put parameter description here>

Field to calculate statistics on

[tablefield: string] <put parameter description here>

Outputs

Statistics for text field

[html] <put output description here>

Minimum length

[number] <put output description here>

Maximum length

[number] <put output description here>

Mean length

[number] <put output description here>

Count

[number] <put output description here>

Number of empty values

[number] <put output description here>

Number of non-empty values

[number] <put output description here>

Number of unique values

[number] <put output description here>

Console usage

processing .

runalg( ’qgis:basicstatisticsfortextfields’ , input_layer, field_name, output_html_file)

See also

Create equivalent numerical field

Description

<put algortithm description here>

Parameters

Input layer

[vector: any] <put parameter description here>

Class field

[tablefield: any] <put parameter description here>

Outputs

Output layer

[vector] <put output description here>

Console usage

processing .

runalg( ’qgis:createequivalentnumericalfield’ , input , field, output)

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See also

Delete column

Description

<put algortithm description here>

Parameters

Input layer

[vector: any] <put parameter description here>

Field to delete

[tablefield: any] <put parameter description here>

Outputs

Output

[vector] <put output description here>

Console usage

processing .

runalg( ’qgis:deletecolumn’ , input , column, output)

See also

Export/Add geometry columns

Description

<put algortithm description here>

Parameters

Input layer

[vector: any] <put parameter description here>

Calculate using

[selection] <put parameter description here>

Options:

• 0 — Layer CRS

• 1 — Project CRS

• 2 — Ellipsoidal

Default: 0

Outputs

Output layer

[vector] <put output description here>

Console usage

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runalg( ’qgis:exportaddgeometrycolumns’ , input , calc_method, output)

See also

Field calculator

Description

<put algortithm description here>

Parameters

Input layer

[vector: any] <put parameter description here>

Result field name

[string] <put parameter description here>

Default: (not set)

Field type

[selection] <put parameter description here>

Options:

• 0 — Float

• 1 — Integer

• 2 — String

• 3 — Date

Default: 0

Field length

[number] <put parameter description here>

Default: 10

Field precision

[number] <put parameter description here>

Default: 3

Create new field

[boolean] <put parameter description here>

Default: True

Formula

[string] <put parameter description here>

Default: (not set)

Outputs

Output layer

[vector] <put output description here>

Console usage

processing .

runalg( ’qgis:fieldcalculator’ , input_layer, field_name, field_type, field_length, field_precision, new_field, formula, output_layer)

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See also

List unique values

Description

Lists unique values of an attribute table field and counts their number.

Parameters

Input layer

[vector: any] Layer to analyze.

Target field

[tablefield: any] Field to analyze.

Outputs

Unique values

[html] Analysis results in HTML format.

Total unique values

[number] Total number of unique values in given field.

Unique values

[string] List of all unique values in given field.

Console usage

processing .

runalg( ’qgis:listuniquevalues’ , input_layer, field_name, output)

See also

Number of unique values in classes

Description

<put algortithm description here>

Parameters input

[vector: any] <put parameter description here>

class field

[tablefield: any] <put parameter description here>

value field

[tablefield: any] <put parameter description here>

Outputs output

[vector] <put output description here>

Console usage

processing .

runalg( ’qgis:numberofuniquevaluesinclasses’ , input , class_field, value_field, output)

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See also

Statistics by categories

Description

<put algortithm description here>

Parameters

Input vector layer

[vector: any] <put parameter description here>

Field to calculate statistics on

[tablefield: numeric] <put parameter description here>

Field with categories

[tablefield: any] <put parameter description here>

Outputs

Statistics

[table] <put output description here>

Console usage

processing .

runalg( ’qgis:statisticsbycategories’ , input_layer, values_field_name, categories_field_name, output)

See also

Text to float

Description

<put algortithm description here>

Parameters

Input Layer

[vector: any] <put parameter description here>

Text attribute to convert to float

[tablefield: string] <put parameter description here>

Outputs

Output

[vector] <put output description here>

Console usage

processing .

runalg( ’qgis:texttofloat’ , input , field, output)

.

See also

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18.6 R algorithm provider

.

R also called GNU S, is a strongly functional language and environment to statistically explore data sets, make many graphical displays of data from custom data sets

Muista: Please remember that Processing contains only R scripts, so you need to install R by yourself and configure Processing properly.

18.6.1 Basic statistics

Frequency table

Description

<put algortithm description here>

Parameters

Layer

[vector: any] <put parameter description here>

Field

[tablefield: any] <put parameter description here>

Outputs

R Console Output

[html] <put output description here>

Console usage

processing .

runalg( ’r:frequencytable’ , layer, field, r_console_output)

See also

Kolmogrov-Smirnov test

Description

<put algortithm description here>

Parameters

Layer

[vector: any] <put parameter description here>

Field

[tablefield: any] <put parameter description here>

Outputs

R Console Output

[html] <put output description here>

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Console usage

processing .

runalg( ’r:kolmogrovsmirnovtest’ , layer, field, r_console_output)

See also

Summary statistics

Description

<put algortithm description here>

Parameters

Layer

[vector: any] <put parameter description here>

Field

[tablefield: any] <put parameter description here>

Outputs

R Console Output

[html] <put output description here>

Console usage

processing .

runalg( ’r:summarystatistics’ , layer, field, r_console_output)

.

See also

18.6.2 Home range

Characteristic hull method

Description

<put algortithm description here>

Parameters

Layer

[vector: any] <put parameter description here>

Field

[tablefield: any] <put parameter description here>

Outputs

Home_ranges

[vector] <put output description here>

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Console usage

processing .

runalg( ’r:characteristichullmethod’ , layer, field, home_ranges)

See also

Kernel h ref

Description

<put algortithm description here>

Parameters

Layer

[vector: any] <put parameter description here>

Field

[tablefield: any] <put parameter description here>

Grid

[number] <put parameter description here>

Default: 10.0

Percentage

[number] <put parameter description here>

Default: 10.0

Folder

[directory] Optional.

<put parameter description here>

Outputs

Home_ranges

[vector] <put output description here>

Console usage

processing .

runalg( ’r:kernelhref’ , layer, field, grid, percentage, folder, home_ranges)

See also

Minimum convex polygon

Description

<put algortithm description here>

Parameters

Layer

[vector: any] <put parameter description here>

Percentage

[number] <put parameter description here>

Default: 10.0

Field

[tablefield: any] <put parameter description here>

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Outputs

Home_ranges

[vector] <put output description here>

Console usage

processing .

runalg( ’r:minimumconvexpolygon’ , layer, percentage, field, home_ranges)

See also

Single-linkage cluster analysis

Description

<put algortithm description here>

Parameters

Layer

[vector: any] <put parameter description here>

Field

[tablefield: any] <put parameter description here>

Percentage

[number] <put parameter description here>

Default: 10.0

Outputs

R Plots

[html] <put output description here>

Home_ranges

[vector] <put output description here>

Console usage

processing .

runalg( ’r:singlelinkageclusteranalysis’ , layer, field, percentage, rplots, home_ranges)

.

See also

18.6.3 Point pattern

F function

Description

<put algortithm description here>

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Parameters

Layer

[vector: any] <put parameter description here>

Nsim

[number] <put parameter description here>

Default: 10.0

Outputs

R Plots

[html] <put output description here>

Console usage

processing .

runalg( ’r:ffunction’ , layer, nsim, rplots)

See also

G function

Description

<put algortithm description here>

Parameters

Layer

[vector: any] <put parameter description here>

Nsim

[number] <put parameter description here>

Default: 10.0

Outputs

R Plots

[html] <put output description here>

Console usage

processing .

runalg( ’r:gfunction’ , layer, nsim, rplots)

See also

Monte-Carlo spatial randomness

Description

<put algortithm description here>

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Parameters

Layer

[vector: any] <put parameter description here>

Simulations

[number] <put parameter description here>

Default: 100.0

Optional plot name

[string] <put parameter description here>

Default: (not set)

Outputs

R Plots

[html] <put output description here>

R Console Output

[html] <put output description here>

Console usage

processing .

runalg( ’r:montecarlospatialrandomness’ , layer, simulations, optional_plot_name, rplots, r_console_output)

See also

Quadrat analysis

Description

<put algortithm description here>

Parameters

Layer

[vector: any] <put parameter description here>

Outputs

R Plots

[html] <put output description here>

R Console Output

[html] <put output description here>

Console usage

processing .

runalg( ’r:quadratanalysis’ , layer, rplots, r_console_output)

See also

Random sampling grid

Description

<put algortithm description here>

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Parameters

Layer

[vector: any] <put parameter description here>

Size

[number] <put parameter description here>

Default: 10.0

Outputs

Output

[vector] <put output description here>

Console usage

processing .

runalg( ’r:randomsamplinggrid’ , layer, size, output)

See also

Regular sampling grid

Description

<put algortithm description here>

Parameters

Layer

[vector: any] <put parameter description here>

Size

[number] <put parameter description here>

Default: 10.0

Outputs

Output

[vector] <put output description here>

Console usage

processing .

runalg( ’r:regularsamplinggrid’ , layer, size, output)

See also

Relative distribution (distance covariate)

Description

<put algortithm description here>

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Parameters

Layer

[vector: any] <put parameter description here>

Covariate

[vector: any] <put parameter description here>

Covariate name

[string] <put parameter description here>

Default: mandatory_covariate_name_(no_spaces)

x label

[string] <put parameter description here>

Default: (not set)

Plot name

[string] <put parameter description here>

Default: (not set)

Legend position

[string] <put parameter description here>

Default: float

Outputs

R Plots

[html] <put output description here>

Console usage

processing .

runalg( ’r:relativedistributiondistancecovariate’ , layer, covariate, covariate_name, x_label, plot_name, legend_position, rplots)

See also

Relative distribution (raster covariate)

Description

<put algortithm description here>

Parameters points

[vector: any] <put parameter description here>

covariate

[raster] <put parameter description here>

covariate name

[string] <put parameter description here>

Default: mandatory_covariate_name_(no_spaces)

x label

[string] <put parameter description here>

Default: (not set)

plot name

[string] <put parameter description here>

Default: (not set)

legend position

[string] <put parameter description here>

Default: float

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Outputs

R Plots

[html] <put output description here>

Console usage

processing .

runalg( ’r:relativedistributionrastercovariate’ , points, covariate, covariate_name, x_label, plot_name, legend_position, rplots)

See also

Ripley - Rasson spatial domain

Description

<put algortithm description here>

Parameters

Layer

[vector: any] <put parameter description here>

Outputs

Output

[vector] <put output description here>

Console usage

processing .

runalg( ’r:ripleyrassonspatialdomain’ , layer, output)

.

See also

18.6.4 Raster processing

Advanced raster histogram

Description

<put algortithm description here>

Parameters

Layer

[raster] <put parameter description here>

Dens or Hist

[string] <put parameter description here>

Default: Hist

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Outputs

R Plots

[html] <put output description here>

Console usage

processing .

runalg( ’r:advancedrasterhistogram’ , layer, dens_or_hist, rplots)

See also

Raster histogram

Description

<put algortithm description here>

Parameters

Layer

[raster] <put parameter description here>

Outputs

R Plots

[html] <put output description here>

Console usage

processing .

runalg( ’r:rasterhistogram’ , layer, rplots)

.

See also

18.6.5 Vector processing

Histogram

Description

<put algortithm description here>

Parameters

Layer

[vector: any] <put parameter description here>

Field

[tablefield: any] <put parameter description here>

Outputs

R Plots

[html] <put output description here>

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Console usage

processing .

runalg( ’r:histogram’ , layer, field, rplots)

.

See also

18.7 SAGA algorithm provider

.

SAGA (System for Automated Geoscientific Analyses) is a free, hybrid, cross-platform GIS software. SAGA provides many geoscientific methods which are bundled in so-called module libraries.

Muista: Please remember that Processing contains only the interface description, so you need to install SAGA by yourself and configure Processing properly.

18.7.1 Geostatistics

Directional statistics for single grid

Description

<put algortithm description here>

Parameters

Grid

[raster] <put parameter description here>

Points

[vector: any] Optional.

<put parameter description here>

Direction [Degree]

[number] <put parameter description here>

Default: 0.0

Tolerance [Degree]

[number] <put parameter description here>

Default: 0.0

Maximum Distance [Cells]

[number] <put parameter description here>

Default: 0

Distance Weighting

[selection] <put parameter description here>

Options:

• 0 — [0] no distance weighting

• 1 — [1] inverse distance to a power

• 2 — [2] exponential

• 3 — [3] gaussian weighting

Default: 0

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Inverse Distance Weighting Power

[number] <put parameter description here>

Default: 1

Inverse Distance Offset

[boolean] <put parameter description here>

Default: True

Gaussian and Exponential Weighting Bandwidth

[number] <put parameter description here>

Default: 1.0

Outputs

Arithmetic Mean

[raster] <put output description here>

Difference from Arithmetic Mean

[raster] <put output description here>

Minimum

[raster] <put output description here>

Maximum

[raster] <put output description here>

Range

[raster] <put output description here>

Variance

[raster] <put output description here>

Standard Deviation

[raster] <put output description here>

Mean less Standard Deviation

[raster] <put output description here>

Mean plus Standard Deviation

[raster] <put output description here>

Deviation from Arithmetic Mean

[raster] <put output description here>

Percentile

[raster] <put output description here>

Directional Statistics for Points

[vector] <put output description here>

Console usage

processing .

runalg( ’saga:directionalstatisticsforsinglegrid’ , grid, points, direction, tolerance, maxdistance, distance_weighting_weighting, distance_weighting_idw_power, distance_weighting_idw_offset, distance_weighting_bandwidth, mean, difmean, min , max , range , var, stddev, stddevlo, stddevhi, devmean, percent, points_out)

See also

Fast representativeness

Description

<put algortithm description here>

Parameters

Input

[raster] <put parameter description here>

Level of Generalisation

[number] <put parameter description here>

Default: 16

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Outputs

Output

[raster] <put output description here>

Output Lod

[raster] <put output description here>

Output Seeds

[raster] <put output description here>

Console usage

processing .

runalg( ’saga:fastrepresentativeness’ , input , lod, result, result_lod, seeds)

See also

Geographically weighted multiple regression (points/grids)

Description

<put algortithm description here>

Parameters

Predictors

[multipleinput: rasters] <put parameter description here>

Output of Regression Parameters

[boolean] <put parameter description here>

Default: True

Points

[vector: point] <put parameter description here>

Dependent Variable

[tablefield: any] <put parameter description here>

Distance Weighting

[selection] <put parameter description here>

Options:

• 0 — [0] no distance weighting

• 1 — [1] inverse distance to a power

• 2 — [2] exponential

• 3 — [3] gaussian weighting

Default: 0

Inverse Distance Weighting Power

[number] <put parameter description here>

Default: 1

Inverse Distance Offset

[boolean] <put parameter description here>

Default: True

Gaussian and Exponential Weighting Bandwidth

[number] <put parameter description here>

Default: 1.0

Search Range

[selection] <put parameter description here>

Options:

• 0 — [0] search radius (local)

• 1 — [1] no search radius (global)

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Default: 0

Search Radius

[number] <put parameter description here>

Default: 100

Search Mode

[selection] <put parameter description here>

Options:

• 0 — [0] all directions

• 1 — [1] quadrants

Default: 0

Number of Points

[selection] <put parameter description here>

Options:

• 0 — [0] maximum number of observations

• 1 — [1] all points

Default: 0

Maximum Number of Observations

[number] <put parameter description here>

Default: 10

Minimum Number of Observations

[number] <put parameter description here>

Default: 4

Outputs

Regression

[raster] <put output description here>

Coefficient of Determination

[raster] <put output description here>

Regression Parameters

[raster] <put output description here>

Residuals

[vector] <put output description here>

Console usage

processing .

runalg( ’saga:geographicallyweightedmultipleregressionpointsgrids’ , predictors, parameters, points, dependent, distance_weighting_weighting, distance_weighting_idw_power, distance_weighting_idw_offset, distance_weighting_bandwidth, range , radius, mode, npoints, maxpoints, minpoints, regression, quality, slopes, residuals)

See also

Geographically weighted multiple regression (points)

Description

<put algortithm description here>

Parameters

Points

[vector: any] <put parameter description here>

Dependent Variable

[tablefield: any] <put parameter description here>

Distance Weighting

[selection] <put parameter description here>

Options:

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• 0 — [0] no distance weighting

• 1 — [1] inverse distance to a power

• 2 — [2] exponential

• 3 — [3] gaussian weighting

Default: 0

Inverse Distance Weighting Power

[number] <put parameter description here>

Default: 1

Inverse Distance Offset

[boolean] <put parameter description here>

Default: True

Gaussian and Exponential Weighting Bandwidth

[number] <put parameter description here>

Default: 1.0

Search Range

[selection] <put parameter description here>

Options:

• 0 — [0] search radius (local)

• 1 — [1] no search radius (global)

Default: 0

Search Radius

[number] <put parameter description here>

Default: 100

Search Mode

[selection] <put parameter description here>

Options:

• 0 — [0] all directions

• 1 — [1] quadrants

Default: 0

Number of Points

[selection] <put parameter description here>

Options:

• 0 — [0] maximum number of observations

• 1 — [1] all points

Default: 0

Maximum Number of Observations

[number] <put parameter description here>

Default: 10

Minimum Number of Observations

[number] <put parameter description here>

Default: 4

Outputs

Regression

[vector] <put output description here>

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Console usage

processing .

runalg( ’saga:geographicallyweightedmultipleregressionpoints’ , points, dependent, distance_weighting_weighting, distance_weighting_idw_power, distance_weighting_idw_offset, distance_weighting_bandwidth, range , radius, mode, npoints, maxpoints, minpoints, regression)

See also

Geographically weighted multiple regression

Description

<put algortithm description here>

Parameters

Points

[vector: point] <put parameter description here>

Dependent Variable

[tablefield: any] <put parameter description here>

Target Grids

[selection] <put parameter description here>

Options:

• 0 — [0] user defined

Default: 0

Distance Weighting

[selection] <put parameter description here>

Options:

• 0 — [0] no distance weighting

• 1 — [1] inverse distance to a power

• 2 — [2] exponential

• 3 — [3] gaussian weighting

Default: 0

Inverse Distance Weighting Power

[number] <put parameter description here>

Default: 1

Inverse Distance Offset

[boolean] <put parameter description here>

Default: True

Gaussian and Exponential Weighting Bandwidth

[number] <put parameter description here>

Default: 1

Search Range

[selection] <put parameter description here>

Options:

• 0 — [0] search radius (local)

• 1 — [1] no search radius (global)

Default: 0

Search Radius

[number] <put parameter description here>

Default: 100

Search Mode

[selection] <put parameter description here>

Options:

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• 0 — [0] all directions

• 1 — [1] quadrants

Default: 0

Number of Points

[selection] <put parameter description here>

Options:

• 0 — [0] maximum number of observations

• 1 — [1] all points

Default: 0

Maximum Number of Observations

[number] <put parameter description here>

Default: 10

Minimum Number of Observations

[number] <put parameter description here>

Default: 4

Output extent

[extent] <put parameter description here>

Default: 0,1,0,1

Cellsize

[number] <put parameter description here>

Default: 100.0

Outputs

Quality

[raster] <put output description here>

Intercept

[raster] <put output description here>

Quality

[raster] <put output description here>

Intercept

[raster] <put output description here>

Console usage

processing .

runalg( ’saga:geographicallyweightedmultipleregression’ , points, dependent, target, distance_weighting_weighting, distance_weighting_idw_power, distance_weighting_idw_offset, distance_weighting_bandwidth, range , radius, mode, npoints, maxpoints, minpoints, output_extent, user_size, user_quality, user_intercept, grid_quality, grid_intercept)

See also

Geographically weighted regression (points/grid)

Description

<put algortithm description here>

Parameters

Predictor

[raster] <put parameter description here>

Points

[vector: point] <put parameter description here>

Dependent Variable

[tablefield: any] <put parameter description here>

Distance Weighting

[selection] <put parameter description here>

Options:

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• 0 — [0] no distance weighting

• 1 — [1] inverse distance to a power

• 2 — [2] exponential

• 3 — [3] gaussian weighting

Default: 0

Inverse Distance Weighting Power

[number] <put parameter description here>

Default: 1

Inverse Distance Offset

[boolean] <put parameter description here>

Default: True

Gaussian and Exponential Weighting Bandwidth

[number] <put parameter description here>

Default: 1.0

Search Range

[selection] <put parameter description here>

Options:

• 0 — [0] search radius (local)

• 1 — [1] no search radius (global)

Default: 0

Search Radius

[number] <put parameter description here>

Default: 0

Search Mode

[selection] <put parameter description here>

Options:

• 0 — [0] all directions

• 1 — [1] quadrants

Default: 0

Number of Points

[selection] <put parameter description here>

Options:

• 0 — [0] maximum number of observations

• 1 — [1] all points

Default: 0

Maximum Number of Observations

[number] <put parameter description here>

Default: 10

Minimum Number of Observations

[number] <put parameter description here>

Default: 4

Outputs

Regression

[raster] <put output description here>

Coefficient of Determination

[raster] <put output description here>

Intercept

[raster] <put output description here>

Slope

[raster] <put output description here>

Residuals

[vector] <put output description here>

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Console usage

processing .

runalg( ’saga:geographicallyweightedregressionpointsgrid’ , predictor, points, dependent, distance_weighting_weighting, distance_weighting_idw_power, distance_weighting_idw_offset, distance_weighting_bandwidth, range , radius, mode, npoints, maxpoints, minpoints, regression, quality, intercept, slope, residuals)

See also

Geographically weighted regression

Description

<put algortithm description here>

Parameters

Points

[vector: point] <put parameter description here>

Dependent Variable

[tablefield: any] <put parameter description here>

Predictor

[tablefield: any] <put parameter description here>

Target Grids

[selection] <put parameter description here>

Options:

• 0 — [0] user defined

Default: 0

Distance Weighting

[selection] <put parameter description here>

Options:

• 0 — [0] no distance weighting

• 1 — [1] inverse distance to a power

• 2 — [2] exponential

• 3 — [3] gaussian weighting

Default: 0

Inverse Distance Weighting Power

[number] <put parameter description here>

Default: 0

Inverse Distance Offset

[boolean] <put parameter description here>

Default: True

Gaussian and Exponential Weighting Bandwidth

[number] <put parameter description here>

Default: 0.0

Search Range

[selection] <put parameter description here>

Options:

• 0 — [0] search radius (local)

• 1 — [1] no search radius (global)

Default: 0

Search Radius

[number] <put parameter description here>

Default: 100

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Search Mode

[selection] <put parameter description here>

Options:

• 0 — [0] all directions

• 1 — [1] quadrants

Default: 0

Number of Points

[selection] <put parameter description here>

Options:

• 0 — [0] maximum number of observations

• 1 — [1] all points

Default: 0

Maximum Number of Observations

[number] <put parameter description here>

Default: 10

Minimum Number of Observations

[number] <put parameter description here>

Default: 4

Output extent

[extent] <put parameter description here>

Default: 0,1,0,1

Cellsize

[number] <put parameter description here>

Default: 100.0

Outputs

Grid

[raster] <put output description here>

Quality

[raster] <put output description here>

Intercept

[raster] <put output description here>

Slope

[raster] <put output description here>

Console usage

processing .

runalg( ’saga:geographicallyweightedregression’ , points, dependent, predictor, target, distance_weighting_weighting, distance_weighting_idw_power, distance_weighting_idw_offset, distance_weighting_bandwidth, range , radius, mode, npoints, maxpoints, minpoints, output_extent, user_size, user_grid, user_quality, user_intercept, user_slope)

See also

Global moran’s i for grids

Description

<put algortithm description here>

Parameters

Grid

[raster] <put parameter description here>

Case of contiguity

[selection] <put parameter description here>

Options:

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• 0 — [0] Rook

• 1 — [1] Queen

Default: 0

Outputs

Result

[table] <put output description here>

Console usage

processing .

runalg( ’saga:globalmoransiforgrids’ , grid, contiguity, result)

See also

Minimum distance analysis

Description

Performs a complete distance analysis of a point layer:

• minimum distance of points

• maximum distance of points

• average distance of all the points

• standard deviation of the distance

• duplicated points

Parameters

Points

[vector: point] Layer to analyze.

Outputs

Minimum Distance Analysis

[table] The resulting table.

Console usage

processing .

runalg( ’saga:minimumdistanceanalysis’ , points, table)

See also

Multi-band variation

Description

<put algortithm description here>

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Parameters

Grids

[multipleinput: rasters] <put parameter description here>

Radius [Cells]

[number] <put parameter description here>

Default: 1

Distance Weighting

[selection] <put parameter description here>

Options:

• 0 — [0] no distance weighting

• 1 — [1] inverse distance to a power

• 2 — [2] exponential

• 3 — [3] gaussian weighting

Default: 0

Inverse Distance Weighting Power

[number] <put parameter description here>

Default: 1

Inverse Distance Offset

[boolean] <put parameter description here>

Default: True

Gaussian and Exponential Weighting Bandwidth

[number] <put parameter description here>

Default: 1.0

Outputs

Mean Distance

[raster] <put output description here>

Standard Deviation

[raster] <put output description here>

Distance

[raster] <put output description here>

Console usage

processing .

runalg( ’saga:multibandvariation’ , bands, radius, distance_weighting_weighting, distance_weighting_idw_power, distance_weighting_idw_offset, distance_weighting_bandwidth, mean, stddev, diff)

See also

Multiple regression analysis (grid/grids)

Description

<put algortithm description here>

Parameters

Dependent

[raster] <put parameter description here>

Grids

[multipleinput: rasters] <put parameter description here>

Grid Interpolation

[selection] <put parameter description here>

Options:

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• 0 — [0] Nearest Neighbor

• 1 — [1] Bilinear Interpolation

• 2 — [2] Inverse Distance Interpolation

• 3 — [3] Bicubic Spline Interpolation

• 4 — [4] B-Spline Interpolation

Default: 0

Include X Coordinate

[boolean] <put parameter description here>

Default: True

Include Y Coordinate

[boolean] <put parameter description here>

Default: True

Method

[selection] <put parameter description here>

Options:

• 0 — [0] include all

• 1 — [1] forward

• 2 — [2] backward

• 3 — [3] stepwise

Default: 0

P in

[number] <put parameter description here>

Default: 5

P out

[number] <put parameter description here>

Default: 5

Outputs

Regression

[raster] <put output description here>

Residuals

[raster] <put output description here>

Details: Coefficients

[table] <put output description here>

Details: Model

[table] <put output description here>

Details: Steps

[table] <put output description here>

Console usage

processing .

runalg( ’saga:multipleregressionanalysisgridgrids’ , dependent, grids, interpol, coord_x, coord_y, method, p_in, p_out, regression, residuals, info_coeff, info_model, info_steps)

See also

Multiple regression analysis (points/grids)

Description

<put algortithm description here>

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Parameters

Grids

[multipleinput: rasters] <put parameter description here>

Shapes

[vector: any] <put parameter description here>

Attribute

[tablefield: any] <put parameter description here>

Grid Interpolation

[selection] <put parameter description here>

Options:

• 0 — [0] Nearest Neighbor

• 1 — [1] Bilinear Interpolation

• 2 — [2] Inverse Distance Interpolation

• 3 — [3] Bicubic Spline Interpolation

• 4 — [4] B-Spline Interpolation

Default: 0

Include X Coordinate

[boolean] <put parameter description here>

Default: True

Include Y Coordinate

[boolean] <put parameter description here>

Default: True

Method

[selection] <put parameter description here>

Options:

• 0 — [0] include all

• 1 — [1] forward

• 2 — [2] backward

• 3 — [3] stepwise

Default: 0

P in

[number] <put parameter description here>

Default: 5

P out

[number] <put parameter description here>

Default: 5

Outputs

Details: Coefficients

[table] <put output description here>

Details: Model

[table] <put output description here>

Details: Steps

[table] <put output description here>

Residuals

[vector] <put output description here>

Regression

[raster] <put output description here>

Console usage

processing .

runalg( ’saga:multipleregressionanalysispointsgrids’ , grids, shapes, attribute, interpol, coord_x, coord_y, method, p_in, p_out, info_coeff, info_model, info_steps, residuals, regression)

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See also

Polynomial regression

Description

<put algortithm description here>

Parameters

Points

[vector: any] <put parameter description here>

Attribute

[tablefield: any] <put parameter description here>

Polynom

[selection] <put parameter description here>

Options:

• 0 — [0] simple planar surface

• 1 — [1] bi-linear saddle

• 2 — [2] quadratic surface

• 3 — [3] cubic surface

• 4 — [4] user defined

Default: 0

Maximum X Order

[number] <put parameter description here>

Default: 4

Maximum Y Order

[number] <put parameter description here>

Default: 4

Maximum Total Order

[number] <put parameter description here>

Default: 4

Trend Surface

[selection] <put parameter description here>

Options:

• 0 — [0] user defined

Default: 0

Output extent

[extent] <put parameter description here>

Default: 0,1,0,1

Cellsize

[number] <put parameter description here>

Default: 100.0

Outputs

Residuals

[vector] <put output description here>

Grid

[raster] <put output description here>

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Console usage

processing .

runalg( ’saga:polynomialregression’ , points, attribute, polynom, xorder, yorder, torder, target, output_extent, user_size, residuals, user_grid)

See also

Radius of variance (grid)

Description

<put algortithm description here>

Parameters

Grid

[raster] <put parameter description here>

Standard Deviation

[number] <put parameter description here>

Default: 1.0

Maximum Search Radius (cells)

[number] <put parameter description here>

Default: 20

Type of Output

[selection] <put parameter description here>

Options:

• 0 — [0] Cells

• 1 — [1] Map Units

Default: 0

Outputs

Variance Radius

[raster] <put output description here>

Console usage

processing .

runalg( ’saga:radiusofvariancegrid’ , input , variance, radius, output, result)

See also

Regression analysis

Description

<put algortithm description here>

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Parameters

Grid

[raster] <put parameter description here>

Shapes

[vector: any] <put parameter description here>

Attribute

[tablefield: any] <put parameter description here>

Grid Interpolation

[selection] <put parameter description here>

Options:

• 0 — [0] Nearest Neighbor

• 1 — [1] Bilinear Interpolation

• 2 — [2] Inverse Distance Interpolation

• 3 — [3] Bicubic Spline Interpolation

• 4 — [4] B-Spline Interpolation

Default: 0

Regression Function

[selection] <put parameter description here>

Options:

• 0 — [0] Y = a + b * X (linear)

• 1 — [1] Y = a + b / X

• 2 — [2] Y = a / (b - X)

• 3 — [3] Y = a * X^b (power)

• 4 — [4] Y = a e^(b * X) (exponential)

• 5 — [5] Y = a + b * ln(X) (logarithmic)

Default: 0

Outputs

Regression

[raster] <put output description here>

Residuals

[vector] <put output description here>

Console usage

processing .

runalg( ’saga:regressionanalysis’ , grid, shapes, attribute, interpol, method, regression, residual)

See also

Representativeness

Description

<put algortithm description here>

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Parameters

Grid

[raster] <put parameter description here>

Radius (Cells)

[number] <put parameter description here>

Default: 10

Exponent

[number] <put parameter description here>

Default: 1

Outputs

Representativeness

[raster] <put output description here>

Console usage

processing .

runalg( ’saga:representativeness’ , input , radius, exponent, result)

See also

Residual analysis

Description

<put algortithm description here>

Parameters

Grid

[raster] <put parameter description here>

Radius (Cells)

[number] <put parameter description here>

Default: 7

Distance Weighting

[selection] <put parameter description here>

Options:

• 0 — [0] no distance weighting

• 1 — [1] inverse distance to a power

• 2 — [2] exponential

• 3 — [3] gaussian weighting

Default: 0

Inverse Distance Weighting Power

[number] <put parameter description here>

Default: 1

Inverse Distance Offset

[boolean] <put parameter description here>

Default: True

Gaussian and Exponential Weighting Bandwidth

[number] <put parameter description here>

Default: 1.0

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Outputs

Mean Value

[raster] <put output description here>

Difference from Mean Value

[raster] <put output description here>

Standard Deviation

[raster] <put output description here>

Value Range

[raster] <put output description here>

Minimum Value

[raster] <put output description here>

Maximum Value

[raster] <put output description here>

Deviation from Mean Value

[raster] <put output description here>

Percentile

[raster] <put output description here>

Console usage

processing .

runalg( ’saga:residualanalysis’ , grid, radius, distance_weighting_weighting, distance_weighting_idw_power, distance_weighting_idw_offset, distance_weighting_bandwidth, mean, diff, stddev, range , min , max , devmean, percent)

See also

Spatial point pattern analysis

Description

<put algortithm description here>

Parameters

Points

[vector: point] <put parameter description here>

Vertex Distance [Degree]

[number] <put parameter description here>

Default: 5

Outputs

Mean Centre

[vector] <put output description here>

Standard Distance

[vector] <put output description here>

Bounding Box

[vector] <put output description here>

Console usage

processing .

runalg( ’saga:spatialpointpatternanalysis’ , points, step, centre, stddist, bbox)

See also

Statistics for grids

Description

<put algortithm description here>

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Parameters

Grids

[multipleinput: rasters] <put parameter description here>

Outputs

Arithmetic Mean

[raster] <put output description here>

Minimum

[raster] <put output description here>

Maximum

[raster] <put output description here>

Variance

[raster] <put output description here>

Standard Deviation

[raster] <put output description here>

Mean less Standard Deviation

[raster] <put output description here>

Mean plus Standard Deviation

[raster] <put output description here>

Console usage

processing .

runalg( ’saga:statisticsforgrids’ , grids, mean, min , max , var, stddev, stddevlo, stddevhi)

See also

Variogram cloud

Description

<put algortithm description here>

Parameters

Points

[vector: point] <put parameter description here>

Attribute

[tablefield: any] <put parameter description here>

Maximum Distance

[number] <put parameter description here>

Default: 0.0

Skip Number

[number] <put parameter description here>

Default: 1

Outputs

Variogram Cloud

[table] <put output description here>

Console usage

processing .

runalg( ’saga:variogramcloud’ , points, field, distmax, nskip, result)

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See also

Variogram surface

Description

<put algortithm description here>

Parameters

Points

[vector: point] <put parameter description here>

Attribute

[tablefield: any] <put parameter description here>

Number of Distance Classes

[number] <put parameter description here>

Default: 10

Skip Number

[number] <put parameter description here>

Default: 1

Outputs

Number of Pairs

[raster] <put output description here>

Variogram Surface

[raster] <put output description here>

Covariance Surface

[raster] <put output description here>

Console usage

processing .

runalg( ’saga:variogramsurface’ , points, field, distcount, nskip, count, variance, covariance)

See also

Zonal grid statistics

Description

<put algortithm description here>

Parameters

Zone Grid

[raster] <put parameter description here>

Categorial Grids

[multipleinput: rasters] Optional.

<put parameter description here>

Grids to analyse

[multipleinput: rasters] Optional.

<put parameter description here>

Aspect

[raster] Optional.

<put parameter description here>

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Short Field Names

[boolean] <put parameter description here>

Default: True

Outputs

Zonal Statistics

[table] <put output description here>

Console usage

processing .

runalg( ’saga:zonalgridstatistics’ , zones, catlist, statlist, aspect, shortnames, outtab)

.

See also

18.7.2 Grid analysis

Accumulated cost (anisotropic)

Description

<put algortithm description here>

Parameters

Cost Grid

[raster] <put parameter description here>

Direction of max cost

[raster] <put parameter description here>

Destination Points

[raster] <put parameter description here>

k factor

[number] <put parameter description here>

Default: 1

Threshold for different route

[number] <put parameter description here>

Default: 0

Outputs

Accumulated Cost

[raster] <put output description here>

Console usage

processing .

runalg( ’saga:accumulatedcostanisotropic’ , cost, direction, points, k, threshold, acccost)

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See also

Accumulated cost (isotropic)

Description

<put algortithm description here>

Parameters

Cost Grid

[raster] <put parameter description here>

Destination Points

[raster] <put parameter description here>

Threshold for different route

[number] <put parameter description here>

Default: 0.0

Outputs

Accumulated Cost

[raster] <put output description here>

Closest Point

[raster] <put output description here>

Console usage

processing .

runalg( ’saga:accumulatedcostisotropic’ , cost, points, threshold, acccost, closestpt)

See also

Aggregation index

Description

<put algortithm description here>

Parameters

Input Grid

[raster] <put parameter description here>

Max. Number of Classes

[number] <put parameter description here>

Default: 5

Outputs

Result

[table] <put output description here>

Console usage

processing .

runalg( ’saga:aggregationindex’ , input , maxnumclass, result)

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See also

Analytical hierarchy process

Description

<put algortithm description here>

Parameters

Input Grids

[multipleinput: rasters] <put parameter description here>

Pairwise Comparisons Table

[table] <put parameter description here>

Outputs

Output Grid

[raster] <put output description here>

Console usage

processing .

runalg( ’saga:analyticalhierarchyprocess’ , grids, table, output)

See also

Cross-classification and tabulation

Description

<put algortithm description here>

Parameters

Input Grid 1

[raster] <put parameter description here>

Input Grid 2

[raster] <put parameter description here>

Max. Number of Classes

[number] <put parameter description here>

Default: 5

Outputs

Cross-Classification Grid

[raster] <put output description here>

Cross-Tabulation Table

[table] <put output description here>

Console usage

processing .

runalg( ’saga:crossclassificationandtabulation’ , input , input2, maxnumclass, resultgrid, resulttable)

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See also

Fragmentation (alternative)

Description

<put algortithm description here>

Parameters

Classification

[raster] <put parameter description here>

Class Identifier

[number] <put parameter description here>

Default: 1

Neighborhood Min

[number] <put parameter description here>

Default: 1

Neighborhood Max

[number] <put parameter description here>

Default: 1

Level Aggregation

[selection] <put parameter description here>

Options:

• 0 — [0] average

• 1 — [1] multiplicative

Default: 0

Add Border

[boolean] <put parameter description here>

Default: True

Connectivity Weighting

[number] <put parameter description here>

Default: 1.1

Minimum Density [Percent]

[number] <put parameter description here>

Default: 10

Minimum Density for Interior Forest [Percent]

[number] <put parameter description here>

Default: 99

Search Distance Increment

[number] <put parameter description here>

Default: 0.0

Density from Neighbourhood

[boolean] <put parameter description here>

Default: True

Outputs

Density [Percent]

[raster] <put output description here>

Connectivity [Percent]

[raster] <put output description here>

Fragmentation

[raster] <put output description here>

Summary

[table] <put output description here>

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Console usage

processing.runalg(’saga:fragmentationalternative’, classes, class, neighborhood_min, neighborhood_max, aggregation, border, weight, density_min, density_int, level_grow, density_mean, density, connectivity, fragmentation, fragstats)

See also

Fragmentation classes from density and connectivity

Description

<put algortithm description here>

Parameters

Density [Percent]

[raster] <put parameter description here>

Connectivity [Percent]

[raster] <put parameter description here>

Add Border

[boolean] <put parameter description here>

Default: True

Connectivity Weighting

[number] <put parameter description here>

Default: 0

Minimum Density [Percent]

[number] <put parameter description here>

Default: 10

Minimum Density for Interior Forest [Percent]

[number] <put parameter description here>

Default: 99

Outputs

Fragmentation

[raster] <put output description here>

Console usage

processing .

runalg( ’saga:fragmentationclassesfromdensityandconnectivity’ , density, connectivity, border, weight, density_min, density_int, fragmentation)

See also

Fragmentation (standard)

Description

<put algortithm description here>

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Parameters

Classification

[raster] <put parameter description here>

Class Identifier

[number] <put parameter description here>

Default: 1

Neighborhood Min

[number] <put parameter description here>

Default: 1

Neighborhood Max

[number] <put parameter description here>

Default: 3

Level Aggregation

[selection] <put parameter description here>

Options:

• 0 — [0] average

• 1 — [1] multiplicative

Default: 0

Add Border

[boolean] <put parameter description here>

Default: True

Connectivity Weighting

[number] <put parameter description here>

Default: 1.1

Minimum Density [Percent]

[number] <put parameter description here>

Default: 10

Minimum Density for Interior Forest [Percent]

[number] <put parameter description here>

Default: 99

Neighborhood Type

[selection] <put parameter description here>

Options:

• 0 — [0] square

• 1 — [1] circle

Default: 0

Include diagonal neighbour relations

[boolean] <put parameter description here>

Default: True

Outputs

Density [Percent]

[raster] <put output description here>

Connectivity [Percent]

[raster] <put output description here>

Fragmentation

[raster] <put output description here>

Summary

[table] <put output description here>

Console usage

processing.runalg(’saga:fragmentationstandard’, classes, class, neighborhood_min, neighborhood_max, aggregation, border, weight, density_min, density_int, circular, diagonal, density, connectivity, fragmentation, fragstats)

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See also

Layer of extreme value

Description

<put algortithm description here>

Parameters

Grids

[multipleinput: rasters] <put parameter description here>

Method

[selection] <put parameter description here>

Options:

• 0 — [0] Maximum

• 1 — [1] Minimum

Default: 0

Outputs

Result

[raster] <put output description here>

Console usage

processing .

runalg( ’saga:layerofextremevalue’ , grids, criteria, result)

See also

Least cost paths

Description

<put algortithm description here>

Parameters

Source Point(s)

[vector: point] <put parameter description here>

Accumulated cost

[raster] <put parameter description here>

Values

[multipleinput: rasters] Optional.

<put parameter description here>

Outputs

Profile (points)

[vector] <put output description here>

Profile (lines)

[vector] <put output description here>

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Console usage

processing .

runalg( ’saga:leastcostpaths’ , source, dem, values, points, line)

See also

Ordered Weighted Averaging

Description

<put algortithm description here>

Parameters

Input Grids

[multipleinput: rasters] <put parameter description here>

Weights

[fixedtable] <put parameter description here>

Outputs

Output Grid

[raster] <put output description here>

Console usage

processing .

runalg( ’saga:orderedweightedaveraging’ , grids, weights, output)

See also

Pattern analysis

Description

<put algortithm description here>

Parameters

Input Grid

[raster] <put parameter description here>

Size of Analysis Window

[selection] <put parameter description here>

Options:

• 0 — [0] 3 X 3

• 1 — [1] 5 X 5

• 2 — [2] 7 X 7

Default: 0

Max. Number of Classes

[number] <put parameter description here>

Default: 0

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Outputs

Relative Richness

[raster] <put output description here>

Diversity

[raster] <put output description here>

Dominance

[raster] <put output description here>

Fragmentation

[raster] <put output description here>

Number of Different Classes

[raster] <put output description here>

Center Versus Neighbours

[raster] <put output description here>

Console usage

processing .

runalg( ’saga:patternanalysis’ , input , winsize, maxnumclass, relative, diversity, dominance, fragmentation, ndc, cvn)

See also

Soil texture classification

Description

<put algortithm description here>

Parameters

Sand

[raster] Optional.

<put parameter description here>

Silt

[raster] Optional.

<put parameter description here>

Clay

[raster] Optional.

<put parameter description here>

Outputs

Soil Texture

[raster] <put output description here>

Sum

[raster] <put output description here>

Console usage

processing .

runalg( ’saga:soiltextureclassification’ , sand, silt, clay, texture, sum )

.

See also

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18.7.3 Grid calculus

Function

Description

<put algortithm description here>

Parameters xmin

[number] <put parameter description here>

Default: 0.0

xmax

[number] <put parameter description here>

Default: 0.0

ymin

[number] <put parameter description here>

Default: 0.0

ymax

[number] <put parameter description here>

Default: 0.0

Formula

[string] <put parameter description here>

Default: (not set)

Outputs

Function

[raster] <put output description here>

Console usage

processing .

runalg( ’saga:function’ , xmin, xmax, ymin, ymax, formul, result)

See also

Fuzzify

Description

<put algortithm description here>

Parameters

Grid

[raster] <put parameter description here>

A

[number] <put parameter description here>

Default: 0.0

B

[number] <put parameter description here>

Default: 0.0

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C

[number] <put parameter description here>

Default: 0.0

D

[number] <put parameter description here>

Default: 0.0

Membership Function Type

[selection] <put parameter description here>

Options:

• 0 — [0] linear

• 1 — [1] sigmoidal

• 2 — [2] j-shaped

Default: 0

Adjust to Grid

[boolean] <put parameter description here>

Default: True

Outputs

Fuzzified Grid

[raster] <put output description here>

Console usage

processing .

runalg( ’saga:fuzzify’ , input , a, b, c, d, type , autofit, output)

See also

Fuzzy intersection (and)

Description

<put algortithm description here>

Parameters

Grids

[multipleinput: rasters] <put parameter description here>

Operator Type

[selection] <put parameter description here>

Options:

• 0 — [0] min(a, b) (non-interactive)

• 1 — [1] a * b

• 2 — [2] max(0, a + b - 1)

Default: 0

Outputs

Intersection

[raster] <put output description here>

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Console usage

processing.runalg(’saga:fuzzyintersectionand’, grids, type, and)

See also

Fuzzy union (or)

Description

<put algortithm description here>

Parameters

Grids

[multipleinput: rasters] <put parameter description here>

Operator Type

[selection] <put parameter description here>

Options:

• 0 — [0] max(a, b) (non-interactive)

• 1 — [1] a + b - a * b

• 2 — [2] min(1, a + b)

Default: 0

Outputs

Union

[raster] <put output description here>

Console usage

processing.runalg(’saga:fuzzyunionor’, grids, type, or)

See also

Geometric figures

Description

Draws simple geometric figures.

Parameters

Cell Count

[number] Number of cells to use.

Default: 0

Cell Size

[number] Size of the single cell.

Default: 0

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Figure

[selection] Type of the figure.

Options:

• 0 — [0] Cone (up)

• 1 — [1] Cone (down)

• 2 — [2] Plane

Default: 0

Direction of Plane [Degree]

[number] Rotation factor in degrees.

Default: 0

Outputs

Result

[raster] The resulting layer.

Console usage

processing .

runalg( ’saga:geometricfigures’ , cell_count, cell_size, figure, plane, result)

See also

Gradient vector from cartesian to polar coordinates

Description

<put algortithm description here>

Parameters

X Component

[raster] <put parameter description here>

Y Component

[raster] <put parameter description here>

Polar Angle Units

[selection] <put parameter description here>

Options:

• 0 — [0] radians

• 1 — [1] degree

Default: 0

Polar Coordinate System

[selection] <put parameter description here>

Options:

• 0 — [0] mathematical

• 1 — [1] geographical

• 2 — [2] user defined

Default: 0

User defined Zero Direction

[number] <put parameter description here>

Default: 0.0

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User defined Orientation

[selection] <put parameter description here>

Options:

• 0 — [0] clockwise

• 1 — [1] counterclockwise

Default: 0

Outputs

Direction

[raster] <put output description here>

Length

[raster] <put output description here>

Console usage

processing .

runalg( ’saga:gradientvectorfromcartesiantopolarcoordinates’ , dx, dy, units, system, system_zero, system_orient, dir , len )

See also

Gradient vector from polar to cartesian coordinates

Description

<put algortithm description here>

Parameters

Direction

[raster] <put parameter description here>

Length

[raster] <put parameter description here>

Polar Angle Units

[selection] <put parameter description here>

Options:

• 0 — [0] radians

• 1 — [1] degree

Default: 0

Polar Coordinate System

[selection] <put parameter description here>

Options:

• 0 — [0] mathematical

• 1 — [1] geographical

• 2 — [2] user defined

Default: 0

User defined Zero Direction

[number] <put parameter description here>

Default: 0.0

User defined Orientation

[selection] <put parameter description here>

Options:

• 0 — [0] clockwise

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• 1 — [1] counterclockwise

Default: 0

Outputs

X Component

[raster] <put output description here>

Y Component

[raster] <put output description here>

Console usage

processing .

runalg( ’saga:gradientvectorfrompolartocartesiancoordinates’ , dir , len , units, system, system_zero, system_orient, dx, dy)

See also

Grid difference

Description

Creates a new grid layer as the result of the difference between two other grid layers.

Parameters

A

[raster] First layer.

B

[raster] Second layer.

Outputs

Difference (A - B)

[raster] The resulting layer.

Console usage

processing .

runalg( ’saga:griddifference’ , a, b, c)

See also

Grid division

Description

Creates a new grid layer as the result of the division between two other grid layers.

Parameters

Dividend

[raster] First layer.

Divisor

[raster] Second layer.

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Outputs

Quotient

[raster] The resulting layer.

Console usage

processing .

runalg( ’saga:griddivision’ , a, b, c)

See also

Grid normalisation

Description

Normalises the grid values according to minimum and maximum values chosen.

Parameters

Grid

[raster] Grid to normalize.

Target Range (min)

[number] Minimum value.

Default: 0

Target Range (max)

[number] Maximum value.

Default: 1

Outputs

Normalised Grid

[raster] The resulting layer.

Console usage

processing .

runalg( ’saga:gridnormalisation’ , input , range_min, range_max, output)

See also

Grids product

Description

<put algortithm description here>

Parameters

Grids

[multipleinput: rasters] <put parameter description here>

Outputs

Product

[raster] <put output description here>

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Console usage

processing .

runalg( ’saga:gridsproduct’ , grids, result)

See also

Grids sum

Description

Creates a new grid layer as the result of the sum of two or more grid layers.

Parameters

Grids

[multipleinput: rasters] Grid layers to sum

Outputs

Sum

[raster] The resulting layer.

Console usage

processing .

runalg( ’saga:gridssum’ , grids, result)

See also

Grid standardisation

Description

Standardises the grid layer values.

Parameters

Grid

[raster] Grid to process.

Stretch Factor

[number] stretching factor.

Default: 1.0

Outputs

Standardised Grid

[raster] The resulting layer.

Console usage

processing .

runalg( ’saga:gridstandardisation’ , input , stretch, output)

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See also

Grid volume

Description

<put algortithm description here>

Parameters

Grid

[raster] <put parameter description here>

Method

[selection] <put parameter description here>

Options:

• 0 — [0] Count Only Above Base Level

• 1 — [1] Count Only Below Base Level

• 2 — [2] Subtract Volumes Below Base Level

• 3 — [3] Add Volumes Below Base Level

Default: 0

Base Level

[number] <put parameter description here>

Default: 0.0

Outputs

Console usage

processing .

runalg( ’saga:gridvolume’ , grid, method, level)

See also

Metric conversions

Description

Performs numerical conversions of the grid values.

Parameters

Grid

[raster] Grid to process.

Conversion

[selection] Conversion type.

Options:

• 0 — [0] radians to degree

• 1 — [1] degree to radians

• 2 — [2] Celsius to Fahrenheit

• 3 — [3] Fahrenheit to Celsius

Default: 0

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Outputs

Converted Grid

[raster] The resulting layer.

Console usage

processing .

runalg( ’saga:metricconversions’ , grid, conversion, conv)

See also

Polynomial trend from grids

Description

<put algortithm description here>

Parameters

Dependent Variables

[multipleinput: rasters] <put parameter description here>

Independent Variable (per Grid and Cell)

[multipleinput: rasters] Optional.

<put parameter description here>

Independent Variable (per Grid)

[fixedtable] <put parameter description here>

Type of Approximated Function

[selection] <put parameter description here>

Options:

• 0 — [0] first order polynom (linear regression)

• 1 — [1] second order polynom

• 2 — [2] third order polynom

• 3 — [3] fourth order polynom

• 4 — [4] fifth order polynom

Default: 0

Outputs

Polynomial Coefficients

[raster] <put output description here>

Coefficient of Determination

[raster] <put output description here>

Console usage

processing .

runalg( ’saga:polynomialtrendfromgrids’ , grids, y_grids, y_table, polynom, parms, quality)

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See also

Random field

Description

Generates a random grid layer.

Parameters

Width (Cells)

[number] Width of the layer in cells.

Default: 100

Height (Cells)

[number] Height of the layer in cells.

Default: 100

Cellsize

[number] Cell size to use.

Default: 100.0

West

[number] West coordinate of the bottom-left corner of the grid.

Default: 0.0

South

[number] South coordinate of the bottom-left corner of the grid.

Default: 0.0

Method

[selection] Statistical method used for the calculation.

Options:

• 0 — [0] Uniform

• 1 — [1] Gaussian

Default: 0

Range Min

[number] Minimum cell value to use.

Default: 0.0

Range Max

[number] Maximum cell value to use.

Default: 1.0

Arithmetic Mean

[number] Mean of all the cell values to use.

Default: 0.0

Standard Deviation

[number] Standard deviation of all the cell values to use.

Default: 1.0

Outputs

Random Field

[raster] The resulting layer.

Console usage

processing .

runalg( ’saga:randomfield’ , nx, ny, cellsize, xmin, ymin, method, range_min, range_max, mean, stddev, output)

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See also

Random terrain generation

Description

<put algortithm description here>

Parameters

Radius (cells)

[number] <put parameter description here>

Default: 10

Iterations

[number] <put parameter description here>

Default: 10

Target Dimensions

[selection] <put parameter description here>

Options:

• 0 — [0] User defined

Default: 0

Grid Size

[number] <put parameter description here>

Default: 1.0

Cols

[number] <put parameter description here>

Default: 100

Rows

[number] <put parameter description here>

Default: 100

Outputs

Grid

[raster] <put output description here>

Console usage

processing .

runalg( ’saga:randomterraingeneration’ , radius, iterations, target_type, user_cell_size, user_cols, user_rows, target_grid)

See also

Raster calculator

Description

<put algortithm description here>

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Parameters

Main input layer

[raster] <put parameter description here>

Additional layers

[multipleinput: rasters] Optional.

<put parameter description here>

Formula

[string] <put parameter description here>

Default: (not set)

Outputs

Result

[raster] <put output description here>

Console usage

processing .

runalg( ’saga:rastercalculator’ , grids, xgrids, formula, result)

.

See also

18.7.4 Grid filter

Dtm filter (slope-based)

Description

<put algortithm description here>

Parameters

Grid to filter

[raster] <put parameter description here>

Search Radius

[number] <put parameter description here>

Default: 2

Approx. Terrain Slope

[number] <put parameter description here>

Default: 30.0

Use Confidence Interval

[boolean] <put parameter description here>

Default: True

Outputs

Bare Earth

[raster] <put output description here>

Removed Objects

[raster] <put output description here>

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Console usage

processing .

runalg( ’saga:dtmfilterslopebased’ , input , radius, terrainslope, stddev, ground, nonground)

See also

Filter clumps

Description

<put algortithm description here>

Parameters

Input Grid

[raster] <put parameter description here>

Min. Size

[number] <put parameter description here>

Default: 10

Outputs

Filtered Grid

[raster] <put output description here>

Console usage

processing .

runalg( ’saga:filterclumps’ , grid, threshold, output)

See also

Gaussian filter

Description

<put algortithm description here>

Parameters

Grid

[raster] <put parameter description here>

Standard Deviation

[number] <put parameter description here>

Default: 1

Search Mode

[selection] <put parameter description here>

Options:

• 0 — [0] Square

• 1 — [1] Circle

Default: 0

Search Radius

[number] <put parameter description here>

Default: 3

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Outputs

Filtered Grid

[raster] <put output description here>

Console usage

processing .

runalg( ’saga:gaussianfilter’ , input , sigma, mode, radius, result)

See also

Laplacian filter

Description

<put algortithm description here>

Parameters

Grid

[raster] <put parameter description here>

Method

[selection] <put parameter description here>

Options:

• 0 — [0] standard kernel 1

• 1 — [1] standard kernel 2

• 2 — [2] Standard kernel 3

• 3 — [3] user defined kernel

Default: 0

Standard Deviation (Percent of Radius)

[number] <put parameter description here>

Default: 0

Radius

[number] <put parameter description here>

Default: 1

Search Mode

[selection] <put parameter description here>

Options:

• 0 — [0] square

• 1 — [1] circle

Default: 0

Outputs

Filtered Grid

[raster] <put output description here>

Console usage

processing .

runalg( ’saga:laplacianfilter’ , input , method, sigma, radius, mode, result)

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See also

Majority filter

Description

<put algortithm description here>

Parameters

Grid

[raster] <put parameter description here>

Search Mode

[selection] <put parameter description here>

Options:

• 0 — [0] Square

• 1 — [1] Circle

Default: 0

Radius

[number] <put parameter description here>

Default: 1

Threshold [Percent]

[number] <put parameter description here>

Default: 0

Outputs

Filtered Grid

[raster] <put output description here>

Console usage

processing .

runalg( ’saga:majorityfilter’ , input , mode, radius, threshold, result)

See also

Morphological filter

Description

<put algortithm description here>

Parameters

Grid

[raster] <put parameter description here>

Search Mode

[selection] <put parameter description here>

Options:

• 0 — [0] Square

• 1 — [1] Circle

Default: 0

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Radius

[number] <put parameter description here>

Default: 1

Method

[selection] <put parameter description here>

Options:

• 0 — [0] Dilation

• 1 — [1] Erosion

• 2 — [2] Opening

• 3 — [3] Closing

Default: 0

Outputs

Filtered Grid

[raster] <put output description here>

Console usage

processing .

runalg( ’saga:morphologicalfilter’ , input , mode, radius, method, result)

See also

Multi direction lee filter

Description

<put algortithm description here>

Parameters

Grid

[raster] <put parameter description here>

Estimated Noise (absolute)

[number] <put parameter description here>

Default: 1.0

Estimated Noise (relative)

[number] <put parameter description here>

Default: 1.0

Weighted

[boolean] <put parameter description here>

Default: True

Method

[selection] <put parameter description here>

Options:

• 0 — [0] noise variance given as absolute value

• 1 — [1] noise variance given relative to mean standard deviation

• 2 — [2] original calculation (Ringeler)

Default: 0

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Outputs

Filtered Grid

[raster] <put output description here>

Minimum Standard Deviation

[raster] <put output description here>

Direction of Minimum Standard Deviation

[raster] <put output description here>

Console usage

processing .

runalg( ’saga:multidirectionleefilter’ , input , noise_abs, noise_rel, weighted, method, result, stddev, dir )

See also

Rank filter

Description

<put algortithm description here>

Parameters

Grid

[raster] <put parameter description here>

Search Mode

[selection] <put parameter description here>

Options:

• 0 — [0] Square

• 1 — [1] Circle

Default: 0

Radius

[number] <put parameter description here>

Default: 1

Rank [Percent]

[number] <put parameter description here>

Default: 50

Outputs

Filtered Grid

[raster] <put output description here>

Console usage

processing .

runalg( ’saga:rankfilter’ , input , mode, radius, rank, result)

See also

Simple filter

Description

<put algortithm description here>

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Parameters

Grid

[raster] <put parameter description here>

Search Mode

[selection] <put parameter description here>

Options:

• 0 — [0] Square

• 1 — [1] Circle

Default: 0

Filter

[selection] <put parameter description here>

Options:

• 0 — [0] Smooth

• 1 — [1] Sharpen

• 2 — [2] Edge

Default: 0

Radius

[number] <put parameter description here>

Default: 2

Outputs

Filtered Grid

[raster] <put output description here>

Console usage

processing .

runalg( ’saga:simplefilter’ , input , mode, method, radius, result)

See also

User defined filter

Description

<put algortithm description here>

Parameters

Grid

[raster] <put parameter description here>

Filter Matrix

[table] Optional.

<put parameter description here>

Default Filter Matrix (3x3)

[fixedtable] <put parameter description here>

Outputs

Filtered Grid

[raster] <put output description here>

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Console usage

processing .

runalg( ’saga:userdefinedfilter’ , input , filter , filter_3x3, result)

.

See also

18.7.5 Grid gridding

Inverse distance weighted

Description

Inverse distance grid interpolation from irregular distributed points.

Parameters

Points

[vector: point] <put parameter description here>

Attribute

[tablefield: any] <put parameter description here>

Target Grid

[selection] <put parameter description here>

Options:

• 0 — [0] user defined

Default: 0

Distance Weighting

[selection] <put parameter description here>

Options:

• 0 — [0] inverse distance to a power

• 1 — [1] linearly decreasing within search radius

• 2 — [2] exponential weighting scheme

• 3 — [3] gaussian weighting scheme

Default: 0

Inverse Distance Power

[number] <put parameter description here>

Default: 2

Exponential and Gaussian Weighting Bandwidth

[number] <put parameter description here>

Default: 1

Search Range

[selection] <put parameter description here>

Options:

• 0 — [0] search radius (local)

• 1 — [1] no search radius (global)

Default: 0

Search Radius

[number] <put parameter description here>

Default: 100.0

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Search Mode

[selection] <put parameter description here>

Options:

• 0 — [0] all directions

• 1 — [1] quadrants

Default: 0

Number of Points

[selection] <put parameter description here>

Options:

• 0 — [0] maximum number of points

• 1 — [1] all points

Default: 0

Maximum Number of Points

[number] <put parameter description here>

Default: 10

Output extent

[extent] <put parameter description here>

Default: 0,1,0,1

Cellsize

[number] <put parameter description here>

Default: 100.0

Outputs

Grid

[raster] <put output description here>

Console usage

processing .

runalg( ’saga:inversedistanceweighted’ , shapes, field, target, weighting, power, bandwidth, range , radius, mode, points, npoints, output_extent, user_size, user_grid)

See also

Kernel density estimation

Description

<put algortithm description here>

Parameters

Points

[vector: point] <put parameter description here>

Weight

[tablefield: any] <put parameter description here>

Radius

[number] <put parameter description here>

Default: 10

Kernel

[selection] <put parameter description here>

Options:

• 0 — [0] quartic kernel

• 1 — [1] gaussian kernel

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Default: 0

Target Grid

[selection] <put parameter description here>

Options:

• 0 — [0] user defined

Default: 0

Output extent

[extent] <put parameter description here>

Default: 0,1,0,1

Cellsize

[number] <put parameter description here>

Default: 100.0

Outputs

Grid

[raster] <put output description here>

Console usage

processing .

runalg( ’saga:kerneldensityestimation’ , points, population, radius, kernel, target, output_extent, user_size, user_grid)

See also

Modifed quadratic shepard

Description

<put algortithm description here>

Parameters

Points

[vector: point] <put parameter description here>

Attribute

[tablefield: any] <put parameter description here>

Target Grid

[selection] <put parameter description here>

Options:

• 0 — [0] user defined

Default: 0

Quadratic Neighbors

[number] <put parameter description here>

Default: 13

Weighting Neighbors

[number] <put parameter description here>

Default: 19

Left

[number] <put parameter description here>

Default: 0.0

Right

[number] <put parameter description here>

Default: 0.0

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Bottom

[number] <put parameter description here>

Default: 0.0

Top

[number] <put parameter description here>

Default: 0.0

Cellsize

[number] <put parameter description here>

Default: 100.0

Outputs

Grid

[raster] <put output description here>

Console usage

processing .

runalg( ’saga:modifedquadraticshepard’ , shapes, field, target, quadratic_neighbors, weighting_neighbors, user_xmin, user_xmax, user_ymin, user_ymax, user_size, user_grid)

See also

Natural neighbour

Description

<put algortithm description here>

Parameters

Points

[vector: point] <put parameter description here>

Attribute

[tablefield: any] <put parameter description here>

Target Grid

[selection] <put parameter description here>

Options:

• 0 — [0] user defined

Default: 0

Sibson

[boolean] <put parameter description here>

Default: True

Output extent

[extent] <put parameter description here>

Default: 0,1,0,1

Cellsize

[number] <put parameter description here>

Default: 100.0

Outputs

Grid

[raster] <put output description here>

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Console usage

processing .

runalg( ’saga:naturalneighbour’ , shapes, field, target, sibson, output_extent, user_size, user_grid)

See also

Nearest neighbour

Description

<put algortithm description here>

Parameters

Points

[vector: point] <put parameter description here>

Attribute

[tablefield: any] <put parameter description here>

Target Grid

[selection] <put parameter description here>

Options:

• 0 — [0] user defined

Default: 0

Output extent

[extent] <put parameter description here>

Default: 0,1,0,1

Cellsize

[number] <put parameter description here>

Default: 100.0

Outputs

Grid

[raster] <put output description here>

Console usage

processing .

runalg( ’saga:nearestneighbour’ , shapes, field, target, output_extent, user_size, user_grid)

See also

Shapes to grid

Description

<put algortithm description here>

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Parameters

Shapes

[vector: any] <put parameter description here>

Attribute

[tablefield: any] <put parameter description here>

Method for Multiple Values

[selection] <put parameter description here>

Options:

• 0 — [0] first

• 1 — [1] last

• 2 — [2] minimum

• 3 — [3] maximum

• 4 — [4] mean

Default: 0

Method for Lines

[selection] <put parameter description here>

Options:

• 0 — [0] thin

• 1 — [1] thick

Default: 0

Preferred Target Grid Type

[selection] <put parameter description here>

Options:

• 0 — [0] Integer (1 byte)

• 1 — [1] Integer (2 byte)

• 2 — [2] Integer (4 byte)

• 3 — [3] Floating Point (4 byte)

• 4 — [4] Floating Point (8 byte)

Default: 0

Output extent

[extent] <put parameter description here>

Default: 0,1,0,1

Cellsize

[number] <put parameter description here>

Default: 100.0

Outputs

Grid

[raster] <put output description here>

Console usage

processing .

runalg( ’saga:shapestogrid’ , input , field, multiple, line_type, grid_type, output_extent, user_size, user_grid)

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See also

Triangulation

Description

<put algortithm description here>

Parameters

Points

[vector: point] <put parameter description here>

Attribute

[tablefield: any] <put parameter description here>

Target Grid

[selection] <put parameter description here>

Options:

• 0 — [0] user defined

Default: 0

Output extent

[extent] <put parameter description here>

Default: 0,1,0,1

Cellsize

[number] <put parameter description here>

Default: 100.0

Outputs

Grid

[raster] <put output description here>

Console usage

processing .

runalg( ’saga:triangulation’ , shapes, field, target, output_extent, user_size, user_grid)

.

See also

18.7.6 Grid spline

B-spline approximation

Description

<put algortithm description here>

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Parameters

Points

[vector: point] <put parameter description here>

Attribute

[tablefield: any] <put parameter description here>

Target Grid

[selection] <put parameter description here>

Options:

• 0 — [0] user defined

Default: 0

Resolution

[number] <put parameter description here>

Default: 1.0

Output extent

[extent] <put parameter description here>

Default: 0,1,0,1

Cellsize

[number] <put parameter description here>

Default: 100.0

Outputs

Grid

[raster] <put output description here>

Console usage

processing .

runalg( ’saga:bsplineapproximation’ , shapes, field, target, level, output_extent, user_size, user_grid)

See also

Cubic spline approximation

Description

<put algortithm description here>

Parameters

Points

[vector: point] <put parameter description here>

Attribute

[tablefield: any] <put parameter description here>

Target Grid

[selection] <put parameter description here>

Options:

• 0 — [0] user defined

Default: 0

Minimal Number of Points

[number] <put parameter description here>

Default: 3

Maximal Number of Points

[number] <put parameter description here>

Default: 20

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Points per Square

[number] <put parameter description here>

Default: 5

Tolerance

[number] <put parameter description here>

Default: 140.0

Output extent

[extent] <put parameter description here>

Default: 0,1,0,1

Cellsize

[number] <put parameter description here>

Default: 100.0

Outputs

Grid

[raster] <put output description here>

Console usage

processing .

runalg( ’saga:cubicsplineapproximation’ , shapes, field, target, npmin, npmax, nppc, k, output_extent, user_size, user_grid)

See also

Multilevel b-spline interpolation (from grid)

Description

<put algortithm description here>

Parameters

Grid

[raster] <put parameter description here>

Target Grid

[selection] <put parameter description here>

Options:

• 0 — [0] user defined

Default: 0

Method

[selection] <put parameter description here>

Options:

• 0 — [0] without B-spline refinement

• 1 — [1] with B-spline refinement

Default: 0

Threshold Error

[number] <put parameter description here>

Default: 0.0001

Maximum Level

[number] <put parameter description here>

Default: 11.0

Data Type

[selection] <put parameter description here>

Options:

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• 0 — [0] same as input grid

• 1 — [1] floating point

Default: 0

Output extent

[extent] <put parameter description here>

Default: 0,1,0,1

Cellsize

[number] <put parameter description here>

Default: 100.0

Outputs

Grid

[raster] <put output description here>

Console usage

processing .

runalg( ’saga:multilevelbsplineinterpolationfromgrid’ , gridpoints, target, method, epsilon, level_max, datatype, output_extent, user_size, user_grid)

See also

Multilevel b-spline interpolation

Description

<put algortithm description here>

Parameters

Points

[vector: point] <put parameter description here>

Attribute

[tablefield: any] <put parameter description here>

Target Grid

[selection] <put parameter description here>

Options:

• 0 — [0] user defined

Default: 0

Method

[selection] <put parameter description here>

Options:

• 0 — [0] without B-spline refinement

• 1 — [1] with B-spline refinement

Default: 0

Threshold Error

[number] <put parameter description here>

Default: 0.0001

Maximum Level

[number] <put parameter description here>

Default: 11.0

Output extent

[extent] <put parameter description here>

Default: 0,1,0,1

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Cellsize

[number] <put parameter description here>

Default: 100.0

Outputs

Grid

[raster] <put output description here>

Console usage

processing .

runalg( ’saga:multilevelbsplineinterpolation’ , shapes, field, target, method, epsilon, level_max, output_extent, user_size, user_grid)

See also

Thin plate spline (global)

Description

<put algortithm description here>

Parameters

Points

[vector: point] <put parameter description here>

Attribute

[tablefield: any] <put parameter description here>

Target Grid

[selection] <put parameter description here>

Options:

• 0 — [0] user defined

Default: 0

Regularisation

[number] <put parameter description here>

Default: 0.0

Output extent

[extent] <put parameter description here>

Default: 0,1,0,1

Cellsize

[number] <put parameter description here>

Default: 100.0

Outputs

Grid

[raster] <put output description here>

Console usage

processing .

runalg( ’saga:thinplatesplineglobal’ , shapes, field, target, regul, output_extent, user_size, user_grid)

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See also

Thin plate spline (local)

Description

<put algortithm description here>

Parameters

Points

[vector: point] <put parameter description here>

Attribute

[tablefield: any] <put parameter description here>

Target Grid

[selection] <put parameter description here>

Options:

• 0 — [0] user defined

Default: 0

Regularisation

[number] <put parameter description here>

Default: 0.0001

Search Radius

[number] <put parameter description here>

Default: 100.0

Search Mode

[selection] <put parameter description here>

Options:

• 0 — [0] all directions

• 1 — [1] quadrants

Default: 0

Points Selection

[selection] <put parameter description here>

Options:

• 0 — [0] all points in search radius

• 1 — [1] maximum number of points

Default: 0

Maximum Number of Points

[number] <put parameter description here>

Default: 10

Output extent

[extent] <put parameter description here>

Default: 0,1,0,1

Cellsize

[number] <put parameter description here>

Default: 100.0

Outputs

Grid

[raster] <put output description here>

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Console usage

processing .

runalg( ’saga:thinplatesplinelocal’ , shapes, field, target, regul, radius, mode, select, maxpoints, output_extent, user_size, user_grid)

See also

Thin plate spline (tin)

Description

<put algortithm description here>

Parameters

Points

[vector: point] <put parameter description here>

Attribute

[tablefield: any] <put parameter description here>

Target Grid

[selection] <put parameter description here>

Options:

• 0 — [0] user defined

Default: 0

Regularisation

[number] <put parameter description here>

Default: 0.0

Neighbourhood

[selection] <put parameter description here>

Options:

• 0 — [0] immediate

• 1 — [1] level 1

• 2 — [2] level 2

Default: 0

Add Frame

[boolean] <put parameter description here>

Default: True

Output extent

[extent] <put parameter description here>

Default: 0,1,0,1

Cellsize

[number] <put parameter description here>

Default: 100.0

Outputs

Grid

[raster] <put output description here>

Console usage

processing .

runalg( ’saga:thinplatesplinetin’ , shapes, field, target, regul, level, frame, output_extent, user_size, user_grid)

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See also

18.7.7 Grid tools

Aggregate

Description

<put algortithm description here>

Parameters

Grid

[raster] <put parameter description here>

Aggregation Size

[number] <put parameter description here>

Default: 3

Method

[selection] <put parameter description here>

Options:

• 0 — [0] Sum

• 1 — [1] Min

• 2 — [2] Max

Default: 0

Outputs

Console usage

processing .

runalg( ’saga:aggregate’ , input , size, method)

See also

Change grid values

Description

<put algortithm description here>

Parameters

Grid

[raster] <put parameter description here>

Replace Condition

[selection] <put parameter description here>

Options:

• 0 — [0] Grid value equals low value

• 1 — [1] Low value < grid value < high value

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• 2 — [2] Low value <= grid value < high value

Default: 0

Lookup Table

[fixedtable] <put parameter description here>

Outputs

Changed Grid

[raster] <put output description here>

Console usage

processing .

runalg( ’saga:changegridvalues’ , grid_in, method, lookup, grid_out)

See also

Close gaps

Description

<put algortithm description here>

Parameters

Grid

[raster] <put parameter description here>

Mask

[raster] Optional.

<put parameter description here>

Tension Threshold

[number] <put parameter description here>

Default: 0.1

Outputs

Changed Grid

[raster] <put output description here>

Console usage

processing .

runalg( ’saga:closegaps’ , input , mask, threshold, result)

See also

Close gaps with spline

Description

<put algortithm description here>

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Parameters

Grid

[raster] <put parameter description here>

Mask

[raster] Optional.

<put parameter description here>

Only Process Gaps with Less Cells

[number] <put parameter description here>

Default: 0

Maximum Points

[number] <put parameter description here>

Default: 1000

Number of Points for Local Interpolation

[number] <put parameter description here>

Default: 10

Extended Neighourhood

[boolean] <put parameter description here>

Default: True

Neighbourhood

[selection] <put parameter description here>

Options:

• 0 — [0] Neumann

• 1 — [1] Moore

Default: 0

Radius (Cells)

[number] <put parameter description here>

Default: 0

Relaxation

[number] <put parameter description here>

Default: 0.0

Outputs

Closed Gaps Grid

[raster] <put output description here>

Console usage

processing .

runalg( ’saga:closegapswithspline’ , grid, mask, maxgapcells, maxpoints, localpoints, extended, neighbours, radius, relaxation, closed)

See also

Close one cell gaps

Description

<put algortithm description here>

Parameters

Grid

[raster] <put parameter description here>

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Outputs

Changed Grid

[raster] <put output description here>

Console usage

processing .

runalg( ’saga:closeonecellgaps’ , input , result)

See also

Convert data storage type

Description

<put algortithm description here>

Parameters

Grid

[raster] <put parameter description here>

Data storage type

[selection] <put parameter description here>

Options:

• 0 — [0] bit

• 1 — [1] unsigned 1 byte integer

• 2 — [2] signed 1 byte integer

• 3 — [3] unsigned 2 byte integer

• 4 — [4] signed 2 byte integer

• 5 — [5] unsigned 4 byte integer

• 6 — [6] signed 4 byte integer

• 7 — [7] 4 byte floating point number

• 8 — [8] 8 byte floating point number

Default: 0

Outputs

Converted Grid

[raster] <put output description here>

Console usage

processing .

runalg( ’saga:convertdatastoragetype’ , input , type , output)

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See also

Crop to data

Description

<put algortithm description here>

Parameters

Input layer

[raster] <put parameter description here>

Outputs

Cropped layer

[raster] <put output description here>

Console usage

processing .

runalg( ’saga:croptodata’ , input , output)

See also

Grid buffer

Description

<put algortithm description here>

Parameters

Features Grid

[raster] <put parameter description here>

Distance

[number] <put parameter description here>

Default: 1000

Buffer Distance

[selection] <put parameter description here>

Options:

• 0 — [0] Fixed

• 1 — [1] Cell value

Default: 0

Outputs

Buffer Grid

[raster] <put output description here>

Console usage

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runalg( ’saga:gridbuffer’ , features, dist, buffertype, buffer )

See also

Grid masking

Description

<put algortithm description here>

Parameters

Grid

[raster] <put parameter description here>

Mask

[raster] <put parameter description here>

Outputs

Masked Grid

[raster] <put output description here>

Console usage

processing .

runalg( ’saga:gridmasking’ , grid, mask, masked)

See also

Grid orientation

Description

<put algortithm description here>

Parameters

Grid

[raster] <put parameter description here>

Method

[selection] <put parameter description here>

Options:

• 0 — [0] Copy

• 1 — [1] Flip

• 2 — [2] Mirror

• 3 — [3] Invert

Default: 0

Outputs

Changed Grid

[raster] <put output description here>

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Console usage

processing .

runalg( ’saga:gridorientation’ , input , method, result)

See also

Grid proximity buffer

Description

<put algortithm description here>

Parameters

Source Grid

[raster] <put parameter description here>

Buffer distance

[number] <put parameter description here>

Default: 500.0

Equidistance

[number] <put parameter description here>

Default: 100.0

Outputs

Distance Grid

[raster] <put output description here>

Allocation Grid

[raster] <put output description here>

Buffer Grid

[raster] <put output description here>

Console usage

processing .

runalg( ’saga:gridproximitybuffer’ , source, dist, ival, distance, alloc, buffer )

See also

Grid shrink/expand

Description

<put algortithm description here>

Parameters

Grid

[raster] <put parameter description here>

Operation

[selection] <put parameter description here>

Options:

• 0 — [0] Shrink

• 1 — [1] Expand

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Default: 0

Search Mode

[selection] <put parameter description here>

Options:

• 0 — [0] Square

• 1 — [1] Circle

Default: 0

Radius

[number] <put parameter description here>

Default: 1

Method

[selection] <put parameter description here>

Options:

• 0 — [0] min

• 1 — [1] max

• 2 — [2] mean

• 3 — [3] majority

Default: 0

Outputs

Result Grid

[raster] <put output description here>

Console usage

processing .

runalg( ’saga:gridshrinkexpand’ , input , operation, mode, radius, method_expand, result)

See also

Invert data/no-data

Description

<put algortithm description here>

Parameters

Grid

[raster] <put parameter description here>

Outputs

Result

[raster] <put output description here>

Console usage

processing .

runalg( ’saga:invertdatanodata’ , input , output)

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See also

Merge raster layers

Description

<put algortithm description here>

Parameters

Grids to Merge

[multipleinput: rasters] <put parameter description here>

Preferred data storage type

[selection] <put parameter description here>

Options:

• 0 — [0] 1 bit

• 1 — [1] 1 byte unsigned integer

• 2 — [2] 1 byte signed integer

• 3 — [3] 2 byte unsigned integer

• 4 — [4] 2 byte signed integer

• 5 — [5] 4 byte unsigned integer

• 6 — [6] 4 byte signed integer

• 7 — [7] 4 byte floating point

• 8 — [8] 8 byte floating point

Default: 0

Interpolation

[selection] <put parameter description here>

Options:

• 0 — [0] Nearest Neighbor

• 1 — [1] Bilinear Interpolation

• 2 — [2] Inverse Distance Interpolation

• 3 — [3] Bicubic Spline Interpolation

• 4 — [4] B-Spline Interpolation

Default: 0

Overlapping Cells

[selection] <put parameter description here>

Options:

• 0 — [0] mean value

• 1 — [1] first value in order of grid list

Default: 0

Outputs

Merged Grid

[raster] <put output description here>

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processing .

runalg( ’saga:mergerasterlayers’ , grids, type , interpol, overlap, merged)

See also

Patching

Description

<put algortithm description here>

Parameters

Grid

[raster] <put parameter description here>

Patch Grid

[raster] <put parameter description here>

Interpolation Method

[selection] <put parameter description here>

Options:

• 0 — [0] Nearest Neighbor

• 1 — [1] Bilinear Interpolation

• 2 — [2] Inverse Distance Interpolation

• 3 — [3] Bicubic Spline Interpolation

• 4 — [4] B-Spline Interpolation

Default: 0

Outputs

Completed Grid

[raster] <put output description here>

Console usage

processing .

runalg( ’saga:patching’ , original, additional, interpolation, completed)

See also

Proximity grid

Description

<put algortithm description here>

Parameters

Features

[raster] <put parameter description here>

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Outputs

Distance

[raster] <put output description here>

Direction

[raster] <put output description here>

Allocation

[raster] <put output description here>

Console usage

processing .

runalg( ’saga:proximitygrid’ , features, distance, direction, allocation)

See also

Reclassify grid values

Description

<put algortithm description here>

Parameters

Grid

[raster] <put parameter description here>

Method

[selection] <put parameter description here>

Options:

• 0 — [0] single

• 1 — [1] range

• 2 — [2] simple table

Default: 0

old value (for single value change)

[number] <put parameter description here>

Default: 0.0

new value (for single value change)

[number] <put parameter description here>

Default: 1.0

operator (for single value change)

[selection] <put parameter description here>

Options:

• 0 — [0] =

• 1 — [1] <

• 2 — [2] <=

• 3 — [3] >=

• 4 — [4] >

Default: 0

minimum value (for range)

[number] <put parameter description here>

Default: 0.0

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maximum value (for range)

[number] <put parameter description here>

Default: 1.0

new value(for range)

[number] <put parameter description here>

Default: 2.0

operator (for range)

[selection] <put parameter description here>

Options:

• 0 — [0] <=

• 1 — [1] <

Default: 0

Lookup Table

[fixedtable] <put parameter description here>

operator (for table)

[selection] <put parameter description here>

Options:

• 0 — [0] min <= value < max

• 1 — [1] min <= value <= max

• 2 — [2] min < value <= max

• 3 — [3] min < value < max

Default: 0

replace no data values

[boolean] <put parameter description here>

Default: True

new value for no data values

[number] <put parameter description here>

Default: 0.0

replace other values

[boolean] <put parameter description here>

Default: True

new value for other values

[number] <put parameter description here>

Default: 0.0

Outputs

Reclassified Grid

[raster] <put output description here>

Console usage

processing .

runalg( ’saga:reclassifygridvalues’ , input , method, old, new, soperator, min , max , rnew, roperator, retab, toperator, nodataopt, nodata, otheropt, others, result)

See also

Resampling

Description

<put algortithm description here>

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Parameters

Grid

[raster] <put parameter description here>

Preserve Data Type

[boolean] <put parameter description here>

Default: True

Target Grid

[selection] <put parameter description here>

Options:

• 0 — [0] user defined

Default: 0

Interpolation Method (Scale Up)

[selection] <put parameter description here>

Options:

• 0 — [0] Nearest Neighbor

• 1 — [1] Bilinear Interpolation

• 2 — [2] Inverse Distance Interpolation

• 3 — [3] Bicubic Spline Interpolation

• 4 — [4] B-Spline Interpolation

• 5 — [5] Mean Value

• 6 — [6] Mean Value (cell area weighted)

• 7 — [7] Minimum Value

• 8 — [8] Maximum Value

• 9 — [9] Majority

Default: 0

Interpolation Method (Scale Down)

[selection] <put parameter description here>

Options:

• 0 — [0] Nearest Neighbor

• 1 — [1] Bilinear Interpolation

• 2 — [2] Inverse Distance Interpolation

• 3 — [3] Bicubic Spline Interpolation

• 4 — [4] B-Spline Interpolation

Default: 0

Output extent

[extent] <put parameter description here>

Default: 0,1,0,1

Cellsize

[number] <put parameter description here>

Default: 100.0

Outputs

Grid

[raster] <put output description here>

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Console usage

processing .

runalg( ’saga:resampling’ , input , keep_type, target, scale_up_method, scale_down_method, output_extent, user_size, user_grid)

See also

Sort grid

Description

<put algortithm description here>

Parameters

Input Grid

[raster] <put parameter description here>

Down sort

[boolean] <put parameter description here>

Default: True

Outputs

Sorted Grid

[raster] <put output description here>

Console usage

processing .

runalg( ’saga:sortgrid’ , grid, down, output)

See also

Split RGB bands

Description

<put algortithm description here>

Parameters

Input layer

[raster] <put parameter description here>

Outputs

Output R band layer

[raster] <put output description here>

Output G band layer

[raster] <put output description here>

Output B band layer

[raster] <put output description here>

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Console usage

processing .

runalg( ’saga:splitrgbbands’ , input , r, g, b)

See also

Threshold buffer

Description

<put algortithm description here>

Parameters

Features Grid

[raster] <put parameter description here>

Value Grid

[raster] <put parameter description here>

Threshold Grid

[raster] Optional.

<put parameter description here>

Threshold

[number] <put parameter description here>

Default: 0.0

Threshold Type

[selection] <put parameter description here>

Options:

• 0 — [0] Absolute

• 1 — [1] Relative from cell value

Default: 0

Outputs

Buffer Grid

[raster] <put output description here>

Console usage

processing .

runalg( ’saga:thresholdbuffer’ , features, value, thresholdgrid, threshold, thresholdtype, buffer )

.

See also

18.7.8 Grid visualization

Histogram surface

Description

<put algortithm description here>

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Parameters

Grid

[raster] <put parameter description here>

Method

[selection] <put parameter description here>

Options:

• 0 — [0] rows

• 1 — [1] columns

• 2 — [2] circle

Default: 0

Outputs

Histogram

[raster] <put output description here>

Console usage

processing .

runalg( ’saga:histogramsurface’ , grid, method, hist)

See also

Rgb composite

Description

<put algortithm description here>

Parameters

R

[raster] <put parameter description here>

G

[raster] <put parameter description here>

B

[raster] <put parameter description here>

Method for R value

[selection] <put parameter description here>

Options:

• 0 — 0 - 255

• 1 — Rescale to 0 - 255

• 2 — User defined rescale

• 3 — Percentiles

• 4 — Percentage of standard deviation

Default: 0

Method for G value

[selection] <put parameter description here>

Options:

• 0 — 0 - 255

• 1 — Rescale to 0 - 255

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• 2 — User defined rescale

• 3 — Percentiles

• 4 — Percentage of standard deviation

Default: 0

Method for B value

[selection] <put parameter description here>

Options:

• 0 — 0 - 255

• 1 — Rescale to 0 - 255

• 2 — User defined rescale

• 3 — Percentiles

• 4 — Percentage of standard deviation

Default: 0

Rescale Range for RED min

[number] <put parameter description here>

Default: 0

Rescale Range for RED max

[number] <put parameter description here>

Default: 255

Percentiles Range for RED max

[number] <put parameter description here>

Default: 1

Percentiles Range for RED max

[number] <put parameter description here>

Default: 99

Percentage of standard deviation for RED

[number] <put parameter description here>

Default: 150.0

Rescale Range for GREEN min

[number] <put parameter description here>

Default: 0

Rescale Range for GREEN max

[number] <put parameter description here>

Default: 255

Percentiles Range for GREEN max

[number] <put parameter description here>

Default: 1

Percentiles Range for GREEN max

[number] <put parameter description here>

Default: 99

Percentage of standard deviation for GREEN

[number] <put parameter description here>

Default: 150.0

Rescale Range for BLUE min

[number] <put parameter description here>

Default: 0

Rescale Range for BLUE max

[number] <put parameter description here>

Default: 255

Percentiles Range for BLUE max

[number] <put parameter description here>

Default: 1

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Percentiles Range for BLUE max

[number] <put parameter description here>

Default: 99

Percentage of standard deviation for BLUE

[number] <put parameter description here>

Default: 150.0

Outputs

Output RGB

[raster] <put output description here>

Console usage

processing .

runalg( ’saga:rgbcomposite’ , grid_r, grid_g, grid_b, r_method, g_method, b_method, r_range_min, r_range_max, r_perctl_min, r_perctl_max, r_percent, g_range_min, g_range_max, g_perctl_min, g_perctl_max, g_percent, b_range_min, b_range_max, b_perctl_min, b_perctl_max, b_percent, grid_rgb)

.

See also

18.7.9 Imagery classification

Change detection

Description

<put algortithm description here>

Parameters

Initial State

[raster] <put parameter description here>

Look-up Table

[table] Optional.

<put parameter description here>

Value

[tablefield: any] <put parameter description here>

Value (Maximum)

[tablefield: any] <put parameter description here>

Name

[tablefield: any] <put parameter description here>

Final State

[raster] <put parameter description here>

Look-up Table

[table] Optional.

<put parameter description here>

Value

[tablefield: any] <put parameter description here>

Value (Maximum)

[tablefield: any] <put parameter description here>

Name

[tablefield: any] <put parameter description here>

Report Unchanged Classes

[boolean] <put parameter description here>

Default: True

Output as...

[selection] <put parameter description here>

Options:

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• 0 — [0] cells

• 1 — [1] percent

• 2 — [2] area

Default: 0

Outputs

Changes

[raster] <put output description here>

Changes

[table] <put output description here>

Console usage

processing .

runalg( ’saga:changedetection’ , initial, ini_lut, ini_lut_min, ini_lut_max, ini_lut_nam, final, fin_lut, fin_lut_min, fin_lut_max, fin_lut_nam, nochange, output, change, changes)

See also

Cluster analysis for grids

Description

<put algortithm description here>

Parameters

Grids

[multipleinput: rasters] <put parameter description here>

Method

[selection] <put parameter description here>

Options:

• 0 — [0] Iterative Minimum Distance (Forgy 1965)

• 1 — [1] Hill-Climbing (Rubin 1967)

• 2 — [2] Combined Minimum Distance / Hillclimbing

Default: 0

Clusters

[number] <put parameter description here>

Default: 5

Normalise

[boolean] <put parameter description here>

Default: True

Old Version

[boolean] <put parameter description here>

Default: True

Outputs

Clusters

[raster] <put output description here>

Statistics

[table] <put output description here>

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Console usage

processing .

runalg( ’saga:clusteranalysisforgrids’ , grids, method, ncluster, normalise, oldversion, cluster, statistics)

See also

Supervised classification

Description

<put algortithm description here>

Parameters

Grids

[multipleinput: rasters] <put parameter description here>

Training Areas

[vector: polygon] <put parameter description here>

Class Identifier

[tablefield: any] <put parameter description here>

Method

[selection] <put parameter description here>

Options:

• 0 — [0] Binary Encoding

• 1 — [1] Parallelepiped

• 2 — [2] Minimum Distance

• 3 — [3] Mahalanobis Distance

• 4 — [4] Maximum Likelihood

• 5 — [5] Spectral Angle Mapping

• 6 — [6] Winner Takes All

Default: 0

Normalise

[boolean] <put parameter description here>

Default: True

Distance Threshold

[number] <put parameter description here>

Default: 0.0

Probability Threshold (Percent)

[number] <put parameter description here>

Default: 0.0

Probability Reference

[selection] <put parameter description here>

Options:

• 0 — [0] absolute

• 1 — [1] relative

Default: 0

Spectral Angle Threshold (Degree)

[number] <put parameter description here>

Default: 0.0

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Outputs

Class Information

[table] <put output description here>

Classification

[raster] <put output description here>

Quality

[raster] <put output description here>

Console usage

processing .

runalg( ’saga:supervisedclassification’ , grids, roi, roi_id, method, normalise, threshold_dist, threshold_prob, relative_prob, threshold_angle, class_info, classes, quality)

.

See also

18.7.10 Imagery RGA

Fast region growing algorithm

Description

<put algortithm description here>

Parameters

Input Grids

[multipleinput: rasters] <put parameter description here>

Seeds Grid

[raster] <put parameter description here>

Smooth Rep

[raster] Optional.

<put parameter description here>

Outputs

Segmente

[raster] <put output description here>

Mean

[raster] <put output description here>

Console usage

processing .

runalg( ’saga:fastregiongrowingalgorithm’ , input , start, rep, result, mean)

.

See also

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18.7.11 Imagery segmentation

Grid skeletonization

Description

<put algortithm description here>

Parameters

Grid

[raster] <put parameter description here>

Method

[selection] <put parameter description here>

Options:

• 0 — [0] Standard

• 1 — [1] Hilditch’s Algorithm

• 2 — [2] Channel Skeleton

Default: 0

Initialisation

[selection] <put parameter description here>

Options:

• 0 — [0] Less than

• 1 — [1] Greater than

Default: 0

Threshold (Init.)

[number] <put parameter description here>

Default: 0.0

Convergence

[number] <put parameter description here>

Default: 3.0

Outputs

Skeleton

[raster] <put output description here>

Skeleton

[vector] <put output description here>

Console usage

processing .

runalg( ’saga:gridskeletonization’ , input , method, init_method, init_threshold, convergence, result, vector)

See also

Seed generation

Description

<put algortithm description here>

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Parameters

Features

[multipleinput: rasters] <put parameter description here>

Bandwidth (Cells)

[number] <put parameter description here>

Default: 2

Type of Surface

[selection] <put parameter description here>

Options:

• 0 — [0] smoothed surface

• 1 — [1] variance (a)

• 2 — [2] variance (b)

Default: 0

Extraction of...

[selection] <put parameter description here>

Options:

• 0 — [0] minima

• 1 — [1] maxima

• 2 — [2] minima and maxima

Default: 0

Feature Aggregation

[selection] <put parameter description here>

Options:

• 0 — [0] additive

• 1 — [1] multiplicative

Default: 0

Normalized

[boolean] <put parameter description here>

Default: True

Outputs

Surface

[raster] <put output description here>

Seeds Grid

[raster] <put output description here>

Seeds

[vector] <put output description here>

Console usage

processing .

runalg( ’saga:seedgeneration’ , grids, factor, type_surface, type_seeds, type_merge, normalize, surface, seeds_grid, seeds)

See also

Simple region growing

Description

<put algortithm description here>

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Parameters

Seeds

[raster] <put parameter description here>

Features

[multipleinput: rasters] <put parameter description here>

Method

[selection] <put parameter description here>

Options:

• 0 — [0] feature space and position

• 1 — [1] feature space

Default: 0

Neighbourhood

[selection] <put parameter description here>

Options:

• 0 — [0] 4 (von Neumann)

• 1 — [1] 8 (Moore)

Default: 0

Variance in Feature Space

[number] <put parameter description here>

Default: 1.0

Variance in Position Space

[number] <put parameter description here>

Default: 1.0

Threshold - Similarity

[number] <put parameter description here>

Default: 0.0

Refresh

[boolean] <put parameter description here>

Default: True

Leaf Size (for Speed Optimisation)

[number] <put parameter description here>

Default: 256

Outputs

Segments

[raster] <put output description here>

Similarity

[raster] <put output description here>

Seeds

[table] <put output description here>

Console usage

processing .

runalg( ’saga:simpleregiongrowing’ , seeds, features, method, neighbour, sig_1, sig_2, threshold, refresh, leafsize, segments, similarity, table)

See also

Watershed segmentation

Description

<put algortithm description here>

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Parameters

Grid

[raster] <put parameter description here>

Output

[selection] <put parameter description here>

Options:

• 0 — [0] Seed Value

• 1 — [1] Segment ID

Default: 0

Method

[selection] <put parameter description here>

Options:

• 0 — [0] Minima

• 1 — [1] Maxima

Default: 0

Join Segments based on Threshold Value

[selection] <put parameter description here>

Options:

• 0 — [0] do not join

• 1 — [1] seed to saddle difference

• 2 — [2] seeds difference

Default: 0

Threshold

[number] <put parameter description here>

Default: 0

Allow Edge Pixels to be Seeds

[boolean] <put parameter description here>

Default: True

Borders

[boolean] <put parameter description here>

Default: True

Outputs

Segments

[raster] <put output description here>

Seed Points

[vector] <put output description here>

Borders

[raster] <put output description here>

Console usage

processing .

runalg( ’saga:watershedsegmentation’ , grid, output, down, join, threshold, edge, bborders, segments, seeds, borders)

.

See also

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18.7.12 Imagery tools

Vegetation index[distance based]

Description

<put algortithm description here>

Parameters

Near Infrared Band

[raster] <put parameter description here>

Red Band

[raster] <put parameter description here>

Slope of the soil line

[number] <put parameter description here>

Default: 0.0

Intercept of the soil line

[number] <put parameter description here>

Default: 0.0

Outputs

PVI (Richardson and Wiegand)

[raster] <put output description here>

PVI (Perry & Lautenschlager)

[raster] <put output description here>

PVI (Walther & Shabaani)

[raster] <put output description here>

PVI (Qi, et al)

[raster] <put output description here>

Console usage

processing .

runalg( ’saga:vegetationindexdistancebased’ , nir, red, slope, intercept, pvi, pvi1, pvi2, pvi3)

See also

Vegetation index[slope based]

Description

<put algortithm description here>

Parameters

Near Infrared Band

[raster] <put parameter description here>

Red Band

[raster] <put parameter description here>

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Outputs

Normalized Difference Vegetation Index

[raster] <put output description here>

Ratio Vegetation Index

[raster] <put output description here>

Transformed Vegetation Index

[raster] <put output description here>

Corrected Transformed Vegetation Index

[raster] <put output description here>

Thiam’s Transformed Vegetation Index

[raster] <put output description here>

Normalized Ratio Vegetation Index

[raster] <put output description here>

Console usage

processing .

runalg( ’saga:vegetationindexslopebased’ , nir, red, ndvi, ratio, tvi, ctvi, ttvi, nratio)

.

See also

18.7.13 Kriging

Ordinary kriging (global)

Description

<put algortithm description here>

Parameters

Points

[vector: point] <put parameter description here>

Attribute

[tablefield: any] <put parameter description here>

Create Variance Grid

[boolean] <put parameter description here>

Default: True

Target Grid

[selection] <put parameter description here>

Options:

• 0 — [0] user defined

Default: 0

Variogram Model

[selection] <put parameter description here>

Options:

• 0 — [0] Spherical Model

• 1 — [1] Exponential Model

• 2 — [2] Gaussian Model

• 3 — [3] Linear Regression

• 4 — [4] Exponential Regression

• 5 — [5] Power Function Regression

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Default: 0

Block Kriging

[boolean] <put parameter description here>

Default: True

Block Size

[number] <put parameter description here>

Default: 100

Logarithmic Transformation

[boolean] <put parameter description here>

Default: True

Nugget

[number] <put parameter description here>

Default: 0.0

Sill

[number] <put parameter description here>

Default: 0.0

Range

[number] <put parameter description here>

Default: 0.0

Linear Regression

[number] <put parameter description here>

Default: 1.0

Exponential Regression

[number] <put parameter description here>

Default: 0.1

Power Function - A

[number] <put parameter description here>

Default: 1.0

Power Function - B

[number] <put parameter description here>

Default: 0.5

Grid Size

[number] <put parameter description here>

Default: 1.0

Fit Extent

[boolean] <put parameter description here>

Default: True

Output extent

[extent] <put parameter description here>

Default: 0,1,0,1

Outputs

Grid

[raster] <put output description here>

Variance

[raster] <put output description here>

Console usage

processing .

runalg( ’saga:ordinarykrigingglobal’ , shapes, field, bvariance, target, model, block, dblock, blog, nugget, sill, range , lin_b, exp_b, pow_a, pow_b, user_cell_size, user_fit_extent, output_extent, grid, variance)

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See also

Ordinary kriging

Description

<put algortithm description here>

Parameters

Points

[vector: point] <put parameter description here>

Attribute

[tablefield: any] <put parameter description here>

Create Variance Grid

[boolean] <put parameter description here>

Default: True

Target Grid

[selection] <put parameter description here>

Options:

• 0 — [0] user defined

Default: 0

Variogram Model

[selection] <put parameter description here>

Options:

• 0 — [0] Spherical Model

• 1 — [1] Exponential Model

• 2 — [2] Gaussian Model

• 3 — [3] Linear Regression

• 4 — [4] Exponential Regression

• 5 — [5] Power Function Regression

Default: 0

Block Kriging

[boolean] <put parameter description here>

Default: True

Block Size

[number] <put parameter description here>

Default: 100

Logarithmic Transformation

[boolean] <put parameter description here>

Default: True

Nugget

[number] <put parameter description here>

Default: 0.0

Sill

[number] <put parameter description here>

Default: 10.0

Range

[number] <put parameter description here>

Default: 100.0

Linear Regression

[number] <put parameter description here>

Default: 1.0

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Exponential Regression

[number] <put parameter description here>

Default: 0.1

Power Function - A

[number] <put parameter description here>

Default: 1

Power Function - B

[number] <put parameter description here>

Default: 0.5

Maximum Search Radius (map units)

[number] <put parameter description here>

Default: 1000.0

Min.Number of m_Points

[number] <put parameter description here>

Default: 4

Max. Number of m_Points

[number] <put parameter description here>

Default: 20

Grid Size

[number] <put parameter description here>

Default: 1.0

Fit Extent

[boolean] <put parameter description here>

Default: True

Output extent

[extent] <put parameter description here>

Default: 0,1,0,1

Outputs

Grid

[raster] <put output description here>

Variance

[raster] <put output description here>

Console usage

processing .

runalg( ’saga:ordinarykriging’ , shapes, field, bvariance, target, model, block, dblock, blog, nugget, sill, range , lin_b, exp_b, pow_a, pow_b, maxradius, npoints_min, npoints_max, user_cell_size, user_fit_extent, output_extent, grid, variance)

See also

Universal kriging (global)

Description

<put algortithm description here>

Parameters

Points

[vector: point] <put parameter description here>

Attribute

[tablefield: any] <put parameter description here>

Create Variance Grid

[boolean] <put parameter description here>

Default: True

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Target Grid

[selection] <put parameter description here>

Options:

• 0 — [0] user defined

Default: 0

Variogram Model

[selection] <put parameter description here>

Options:

• 0 — [0] Spherical Model

• 1 — [1] Exponential Model

• 2 — [2] Gaussian Model

• 3 — [3] Linear Regression

• 4 — [4] Exponential Regression

• 5 — [5] Power Function Regression

Default: 0

Block Kriging

[boolean] <put parameter description here>

Default: True

Block Size

[number] <put parameter description here>

Default: 100

Logarithmic Transformation

[boolean] <put parameter description here>

Default: True

Nugget

[number] <put parameter description here>

Default: 0.0

Sill

[number] <put parameter description here>

Default: 0.0

Range

[number] <put parameter description here>

Default: 0.0

Linear Regression

[number] <put parameter description here>

Default: 1

Exponential Regression

[number] <put parameter description here>

Default: 0.5

Power Function - A

[number] <put parameter description here>

Default: 1.0

Power Function - B

[number] <put parameter description here>

Default: 0.1

Grids

[multipleinput: rasters] <put parameter description here>

Grid Interpolation

[selection] <put parameter description here>

Options:

• 0 — [0] Nearest Neighbor

• 1 — [1] Bilinear Interpolation

• 2 — [2] Inverse Distance Interpolation

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• 3 — [3] Bicubic Spline Interpolation

• 4 — [4] B-Spline Interpolation

Default: 0

Grid Size

[number] <put parameter description here>

Default: 1.0

Fit Extent

[boolean] <put parameter description here>

Default: True

Output extent

[extent] <put parameter description here>

Default: 0,1,0,1

Outputs

Grid

[raster] <put output description here>

Variance

[raster] <put output description here>

Console usage

processing .

runalg( ’saga:universalkrigingglobal’ , shapes, field, bvariance, target, model, block, dblock, blog, nugget, sill, range , lin_b, exp_b, pow_a, pow_b, grids, interpol, user_cell_size, user_fit_extent, output_extent, grid, variance)

See also

Universal kriging

Description

<put algortithm description here>

Parameters

Points

[vector: point] <put parameter description here>

Attribute

[tablefield: any] <put parameter description here>

Create Variance Grid

[boolean] <put parameter description here>

Default: True

Target Grid

[selection] <put parameter description here>

Options:

• 0 — [0] user defined

Default: 0

Variogram Model

[selection] <put parameter description here>

Options:

• 0 — [0] Spherical Model

• 1 — [1] Exponential Model

• 2 — [2] Gaussian Model

• 3 — [3] Linear Regression

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• 4 — [4] Exponential Regression

• 5 — [5] Power Function Regression

Default: 0

Block Kriging

[boolean] <put parameter description here>

Default: True

Block Size

[number] <put parameter description here>

Default: 100

Logarithmic Transformation

[boolean] <put parameter description here>

Default: True

Nugget

[number] <put parameter description here>

Default: 0.0

Sill

[number] <put parameter description here>

Default: 0.0

Range

[number] <put parameter description here>

Default: 0.0

Linear Regression

[number] <put parameter description here>

Default: 1.0

Exponential Regression

[number] <put parameter description here>

Default: 0.1

Power Function - A

[number] <put parameter description here>

Default: 1

Power Function - B

[number] <put parameter description here>

Default: 0.5

Grids

[multipleinput: rasters] <put parameter description here>

Grid Interpolation

[selection] <put parameter description here>

Options:

• 0 — [0] Nearest Neighbor

• 1 — [1] Bilinear Interpolation

• 2 — [2] Inverse Distance Interpolation

• 3 — [3] Bicubic Spline Interpolation

• 4 — [4] B-Spline Interpolation

Default: 0

Min.Number of m_Points

[number] <put parameter description here>

Default: 4

Max. Number of m_Points

[number] <put parameter description here>

Default: 20

Maximum Search Radius (map units)

[number] <put parameter description here>

Default: 1000.0

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Grid Size

[number] <put parameter description here>

Default: 1.0

Fit Extent

[boolean] <put parameter description here>

Default: True

Output extent

[extent] <put parameter description here>

Default: 0,1,0,1

Outputs

Grid

[raster] <put output description here>

Variance

[raster] <put output description here>

Console usage

processing .

runalg( ’saga:universalkriging’ , shapes, field, bvariance, target, model, block, dblock, blog, nugget, sill, range , lin_b, exp_b, pow_a, pow_b, grids, interpol, npoints_min, npoints_max, maxradius, user_cell_size, user_fit_extent, output_extent, grid, variance)

.

See also

18.7.14 Shapes grid

Add grid values to points

Description

Creates a new vector layer as a result of the union of a points layer with the interpolated value of one or more base background grid layer(s). This way, the new layer created will have a new column in the attribute table that reflects the interpolated value of the background grid.

Parameters

Points

[vector: point] Input layer.

Grids

[multipleinput: rasters] Background grid layer(s)

Interpolation

[selection] interpolation method to use.

Options:

• 0 — [0] Nearest Neighbor

• 1 — [1] Bilinear Interpolation

• 2 — [2] Inverse Distance Interpolation

• 3 — [3] Bicubic Spline Interpolation

• 4 — [4] B-Spline Interpolation

Default: 0

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Outputs

Result

[vector] The resulting layer.

Console usage

processing .

runalg( ’saga:addgridvaluestopoints’ , shapes, grids, interpol, result)

See also

Add grid values to shapes

Description

<put algortithm description here>

Parameters

Shapes

[vector: any] <put parameter description here>

Grids

[multipleinput: rasters] <put parameter description here>

Interpolation

[selection] <put parameter description here>

Options:

• 0 — [0] Nearest Neighbor

• 1 — [1] Bilinear Interpolation

• 2 — [2] Inverse Distance Interpolation

• 3 — [3] Bicubic Spline Interpolation

• 4 — [4] B-Spline Interpolation

Default: 0

Outputs

Result

[vector] <put output description here>

Console usage

processing .

runalg( ’saga:addgridvaluestoshapes’ , shapes, grids, interpol, result)

See also

Clip grid with polygon

Description

<put algortithm description here>

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Parameters

Input

[raster] <put parameter description here>

Polygons

[vector: polygon] <put parameter description here>

Outputs

Output

[raster] <put output description here>

Console usage

processing .

runalg( ’saga:clipgridwithpolygon’ , input , polygons, output)

See also

Contour lines from grid

Description

<put algortithm description here>

Parameters

Grid

[raster] <put parameter description here>

Minimum Contour Value

[number] <put parameter description here>

Default: 0.0

Maximum Contour Value

[number] <put parameter description here>

Default: 10000.0

Equidistance

[number] <put parameter description here>

Default: 100.0

Outputs

Contour Lines

[vector] <put output description here>

Console usage

processing .

runalg( ’saga:contourlinesfromgrid’ , input , zmin, zmax, zstep, contour)

See also

Gradient vectors from directional components

Description

<put algortithm description here>

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Parameters

X Component

[raster] <put parameter description here>

Y Component

[raster] <put parameter description here>

Step

[number] <put parameter description here>

Default: 1

Size Range Min

[number] <put parameter description here>

Default: 25.0

Size Range Max

[number] <put parameter description here>

Default: 100.0

Aggregation

[selection] <put parameter description here>

Options:

• 0 — [0] nearest neighbour

• 1 — [1] mean value

Default: 0

Style

[selection] <put parameter description here>

Options:

• 0 — [0] simple line

• 1 — [1] arrow

• 2 — [2] arrow (centered to cell)

Default: 0

Outputs

Gradient Vectors

[vector] <put output description here>

Console usage

processing .

runalg( ’saga:gradientvectorsfromdirectionalcomponents’ , x, y, step, size_min, size_max, aggr, style, vectors)

See also

Gradient vectors from direction and length

Description

<put algortithm description here>

Parameters

Direction

[raster] <put parameter description here>

Length

[raster] <put parameter description here>

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Step

[number] <put parameter description here>

Default: 1

Size Range Min

[number] <put parameter description here>

Default: 25.0

Size Range Max

[number] <put parameter description here>

Default: 100.0

Aggregation

[selection] <put parameter description here>

Options:

• 0 — [0] nearest neighbour

• 1 — [1] mean value

Default: 0

Style

[selection] <put parameter description here>

Options:

• 0 — [0] simple line

• 1 — [1] arrow

• 2 — [2] arrow (centered to cell)

Default: 0

Outputs

Gradient Vectors

[vector] <put output description here>

Console usage

processing .

runalg( ’saga:gradientvectorsfromdirectionandlength’ , dir , len , step, size_min, size_max, aggr, style, vectors)

See also

Gradient vectors from surface

Description

<put algortithm description here>

Parameters

Surface

[raster] <put parameter description here>

Step

[number] <put parameter description here>

Default: 1

Size Range Min

[number] <put parameter description here>

Default: 25.0

Size Range Max

[number] <put parameter description here>

Default: 100.0

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Aggregation

[selection] <put parameter description here>

Options:

• 0 — [0] nearest neighbour

• 1 — [1] mean value

Default: 0

Style

[selection] <put parameter description here>

Options:

• 0 — [0] simple line

• 1 — [1] arrow

• 2 — [2] arrow (centered to cell)

Default: 0

Outputs

Gradient Vectors

[vector] <put output description here>

Console usage

processing .

runalg( ’saga:gradientvectorsfromsurface’ , surface, step, size_min, size_max, aggr, style, vectors)

See also

Grid statistics for polygons

Description

<put algortithm description here>

Parameters

Grids

[multipleinput: rasters] <put parameter description here>

Polygons

[vector: polygon] <put parameter description here>

Number of Cells

[boolean] <put parameter description here>

Default: True

Minimum

[boolean] <put parameter description here>

Default: True

Maximum

[boolean] <put parameter description here>

Default: True

Range

[boolean] <put parameter description here>

Default: True

Sum

[boolean] <put parameter description here>

Default: True

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Mean

[boolean] <put parameter description here>

Default: True

Variance

[boolean] <put parameter description here>

Default: True

Standard Deviation

[boolean] <put parameter description here>

Default: True

Quantiles

[number] <put parameter description here>

Default: 0

Outputs

Statistics

[vector] <put output description here>

Console usage

processing .

runalg( ’saga:gridstatisticsforpolygons’ , grids, polygons, count, min , max , range , sum , mean, var, stddev, quantile, result)

See also

Grid values to points (randomly)

Description

<put algortithm description here>

Parameters

Grid

[raster] <put parameter description here>

Frequency

[number] <put parameter description here>

Default: 100

Outputs

Points

[vector] <put output description here>

Console usage

processing .

runalg( ’saga:gridvaluestopointsrandomly’ , grid, freq, points)

See also

Grid values to points

Description

<put algortithm description here>

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Parameters

Grids

[multipleinput: rasters] <put parameter description here>

Polygons

[vector: any] Optional.

<put parameter description here>

Exclude NoData Cells

[boolean] <put parameter description here>

Default: True

Type

[selection] <put parameter description here>

Options:

• 0 — [0] nodes

• 1 — [1] cells

Default: 0

Outputs

Shapes

[vector] <put output description here>

Console usage

processing .

runalg( ’saga:gridvaluestopoints’ , grids, polygons, nodata, type , shapes)

See also

Local minima and maxima

Description

<put algortithm description here>

Parameters

Grid

[raster] <put parameter description here>

Outputs

Minima

[vector] <put output description here>

Maxima

[vector] <put output description here>

Console usage

processing .

runalg( ’saga:localminimaandmaxima’ , grid, minima, maxima)

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See also

Vectorising grid classes

Description

<put algortithm description here>

Parameters

Grid

[raster] <put parameter description here>

Class Selection

[selection] <put parameter description here>

Options:

• 0 — [0] one single class specified by class identifier

• 1 — [1] all classes

Default: 0

Class Identifier

[number] <put parameter description here>

Default: 0

Vectorised class as...

[selection] <put parameter description here>

Options:

• 0 — [0] one single (multi-)polygon object

• 1 — [1] each island as separated polygon

Default: 0

Outputs

Polygons

[vector] <put output description here>

Console usage

processing .

runalg( ’saga:vectorisinggridclasses’ , grid, class_all, class_id, split, polygons)

.

See also

18.7.15 Shapes lines

Convert points to line(s)

Description

Converts points to lines.

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Parameters

Points

[vector: point] Points to convert.

Order by...

[tablefield: any] Lines will be ordered following this field.

Separate by...

[tablefield: any] Lines will be grouped according to this field.

Outputs

Lines

[vector] The resulting layer.

Console usage

processing .

runalg( ’saga:convertpointstolines’ , points, order, separate, lines)

See also

Convert polygons to lines

Description

Creates lines from polygons.

Parameters

Polygons

[vector: polygon] Layer to process.

Outputs

Lines

[vector] The resulting layer.

Console usage

processing .

runalg( ’saga:convertpolygonstolines’ , polygons, lines)

See also

Line dissolve

Description

<put algortithm description here>

Parameters

Lines

[vector: any] <put parameter description here>

1. Attribute

[tablefield: any] <put parameter description here>

2. Attribute

[tablefield: any] <put parameter description here>

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3. Attribute

[tablefield: any] <put parameter description here>

Dissolve...

[selection] <put parameter description here>

Options:

• 0 — [0] lines with same attribute value(s)

• 1 — [1] all lines

Default: 0

Outputs

Dissolved Lines

[vector] <put output description here>

Console usage

processing .

runalg( ’saga:linedissolve’ , lines, field_1, field_2, field_3, all , dissolved)

See also

Line-polygon intersection

Description

<put algortithm description here>

Parameters

Lines

[vector: line] <put parameter description here>

Polygons

[vector: polygon] <put parameter description here>

Output

[selection] <put parameter description here>

Options:

• 0 — [0] one multi-line per polygon

• 1 — [1] keep original line attributes

Default: 0

Outputs

Intersection

[vector] <put output description here>

Console usage

processing .

runalg( ’saga:linepolygonintersection’ , lines, polygons, method, intersect)

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See also

Line properties

Description

Calculates some information on each line of the layer.

Parameters

Lines

[vector: line] Layer to analyze.

Number of Parts

[boolean] Determites whether to calculate number of segments in line.

Default: True

Number of Vertices

[boolean] Determites whether to calculate number of vertices in line.

Default: True

Length

[boolean] Determites whether to calculate total line lenght.

Default: True

Outputs

Lines with Property Attributes

[vector] The resulting layer.

Console usage

processing .

runalg( ’saga:lineproperties’ , lines, bparts, bpoints, blength, output)

See also

Line simplification

Description

Simplyfies the geometry of a lines layer.

Parameters

Lines

[vector: line] Layer to process.

Tolerance

[number] Simplification tolerance.

Default: 1.0

Outputs

Simplified Lines

[vector] The resulting layer.

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Console usage

processing .

runalg( ’saga:linesimplification’ , lines, tolerance, output)

.

See also

18.7.16 Shapes points

Add coordinates to points

Description

Adds the X and Y coordinates of feature in the attribute table of input layer.

Parameters

Points

[vector: point] Input layer.

Outputs

Output

[vector] Resulting layer with the updated attribute table.

Console usage

processing .

runalg( ’saga:addcoordinatestopoints’ , input , output)

See also

Add polygon attributes to points

Description

Adds the specified field of the polygons layer to the attribute table of the points layer. The new attributes added for each point depend on the value of the background polygon layer.

Parameters

Points

[vector: point] Points layer.

Polygons

[vector: polygon] Background polygons layer.

Attribute

[tablefield: any] Attribute of the polygons layer that will be added to the points layer.

Outputs

Result

[vector] The resulting layer.

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Console usage

processing .

runalg( ’saga:addpolygonattributestopoints’ , input , polygons, field, output)

See also

Aggregate point observations

Description

<put algortithm description here>

Parameters

Reference Points

[vector: any] <put parameter description here>

ID

[tablefield: any] <put parameter description here>

Observations

[table] <put parameter description here>

X

[tablefield: any] <put parameter description here>

Y

[tablefield: any] <put parameter description here>

Track

[tablefield: any] <put parameter description here>

Date

[tablefield: any] <put parameter description here>

Time

[tablefield: any] <put parameter description here>

Parameter

[tablefield: any] <put parameter description here>

Maximum Time Span (Seconds)

[number] <put parameter description here>

Default: 60.0

Maximum Distance

[number] <put parameter description here>

Default: 0.002

Outputs

Aggregated

[table] <put output description here>

Console usage

processing .

runalg( ’saga:aggregatepointobservations’ , reference, reference_id, observations, x, y, track, date, time, parameter, eps_time, eps_space, aggregated)

See also

Clip points with polygons

Description

<put algortithm description here>

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Parameters

Points

[vector: point] <put parameter description here>

Polygons

[vector: polygon] <put parameter description here>

Add Attribute to Clipped Points

[tablefield: any] <put parameter description here>

Clipping Options

[selection] <put parameter description here>

Options:

• 0 — [0] one layer for all points

• 1 — [1] separate layer for each polygon

Default: 0

Outputs

Clipped Points

[vector] <put output description here>

Console usage

processing .

runalg( ’saga:clippointswithpolygons’ , points, polygons, field, method, clips)

See also

Convert lines to points

Description

Converts lines layer into a points.

Parameters

Lines

[vector: line] Lines layer to convert.

Insert Additional Points

[boolean] Determines whether to add additional nodes or not.

Default: True

Insert Distance

[number] Distance between the additional points.

Default: 1.0

Outputs

Points

[vector] The resulting layer.

Console usage

processing .

runalg( ’saga:convertlinestopoints’ , lines, add, dist, points)

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See also

Convert multipoints to points

Description

<put algortithm description here>

Parameters

Multipoints

[vector: point] <put parameter description here>

Outputs

Points

[vector] <put output description here>

Console usage

processing .

runalg( ’saga:convertmultipointstopoints’ , multipoints, points)

See also

Convex hull

Description

<put algortithm description here>

Parameters

Points

[vector: point] <put parameter description here>

Hull Construction

[selection] <put parameter description here>

Options:

• 0 — [0] one hull for all shapes

• 1 — [1] one hull per shape

• 2 — [2] one hull per shape part

Default: 0

Outputs

Convex Hull

[vector] <put output description here>

Minimum Bounding Box

[vector] <put output description here>

Console usage

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runalg( ’saga:convexhull’ , shapes, polypoints, hulls, boxes)

See also

Distance matrix

Description

Generates a distance matrix between each point of the input layer. A unique ID will be created in the first row of the resulting matrix (symmetric matrix), while every other cell reflects the distance between the points.

Parameters

Points

[vector: point] Input layer.

Outputs

Distance Matrix Table

[table] The resulting table.

Console usage

processing .

runalg( ’saga:distancematrix’ , points, table)

See also

Fit n points to shape

Description

<put algortithm description here>

Parameters

Shapes

[vector: polygon] <put parameter description here>

Number of points

[number] <put parameter description here>

Default: 10

Outputs

Points

[vector] <put output description here>

Console usage

processing .

runalg( ’saga:fitnpointstoshape’ , shapes, numpoints, points)

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See also

Points filter

Description

<put algortithm description here>

Parameters

Points

[vector: point] <put parameter description here>

Attribute

[tablefield: any] <put parameter description here>

Radius

[number] <put parameter description here>

Default: 1

Minimum Number of Points

[number] <put parameter description here>

Default: 0

Maximum Number of Points

[number] <put parameter description here>

Default: 0

Quadrants

[boolean] <put parameter description here>

Default: True

Filter Criterion

[selection] <put parameter description here>

Options:

• 0 — [0] keep maxima (with tolerance)

• 1 — [1] keep minima (with tolerance)

• 2 — [2] remove maxima (with tolerance)

• 3 — [3] remove minima (with tolerance)

• 4 — [4] remove below percentile

• 5 — [5] remove above percentile

Default: 0

Tolerance

[number] <put parameter description here>

Default: 0.0

Percentile

[number] <put parameter description here>

Default: 50

Outputs

Filtered Points

[vector] <put output description here>

Console usage

processing .

runalg( ’saga:pointsfilter’ , points, field, radius, minnum, maxnum, quadrants, method, tolerance, percent, filter )

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See also

Points thinning

Description

<put algortithm description here>

Parameters

Points

[vector: point] <put parameter description here>

Attribute

[tablefield: any] <put parameter description here>

Resolution

[number] <put parameter description here>

Default: 1.0

Outputs

Thinned Points

[vector] <put output description here>

Console usage

processing .

runalg( ’saga:pointsthinning’ , points, field, resolution, thinned)

See also

Remove duplicate points

Description

<put algortithm description here>

Parameters

Points

[vector: any] <put parameter description here>

Attribute

[tablefield: any] <put parameter description here>

Point to Keep

[selection] <put parameter description here>

Options:

• 0 — [0] first point

• 1 — [1] last point

• 2 — [2] point with minimum attribute value

• 3 — [3] point with maximum attribute value

Default: 0

Numeric Attribute Values

[selection] <put parameter description here>

Options:

• 0 — [0] take value from the point to be kept

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• 1 — [1] minimum value of all duplicates

• 2 — [2] maximum value of all duplicates

• 3 — [3] mean value of all duplicates

Default: 0

Outputs

Result

[vector] <put output description here>

Console usage

processing .

runalg( ’saga:removeduplicatepoints’ , points, field, method, numeric, result)

See also

Separate points by direction

Description

<put algortithm description here>

Parameters

Points

[vector: point] <put parameter description here>

Number of Directions

[number] <put parameter description here>

Default: 4

Tolerance (Degree)

[number] <put parameter description here>

Default: 5

Outputs

Ouput

[vector] <put output description here>

Console usage

processing .

runalg( ’saga:separatepointsbydirection’ , points, directions, tolerance, output)

.

See also

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18.7.17 Shapes polygons

Convert lines to polygons

Description

Converts lines to polygons.

Parameters

Lines

[vector: line] Lines to convert.

Outputs

Polygons

[vector] The resulting layer.

Console usage

processing .

runalg( ’saga:convertlinestopolygons’ , lines, polygons)

See also

Convert polygon/line vertices to points

Description

Converts the line or polygon vertices into points.

Parameters

Shapes

[vector: any] Layer to process.

Outputs

Points

[vector] The resulting layer.

Console usage

processing .

runalg( ’saga:convertpolygonlineverticestopoints’ , shapes, points)

See also

Polygon centroids

Description

Calculates the centroids of polygons.

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Parameters

Polygons

[vector: polygon] Input layer.

Centroids for each part

[boolean] Determites whether centroids should be calculated for each part of multipart polygon or not.

Default: True

Outputs

Centroids

[vector] The resulting layer.

Console usage

processing .

runalg( ’saga:polygoncentroids’ , polygons, method, centroids)

See also

Polygon dissolve

Description

<put algortithm description here>

Parameters

Polygons

[vector: polygon] <put parameter description here>

1. Attribute

[tablefield: any] Optional.

<put parameter description here>

2. Attribute

[tablefield: any] Optional.

<put parameter description here>

3. Attribute

[tablefield: any] Optional.

<put parameter description here>

Dissolve...

[selection] <put parameter description here>

Options:

• 0 — [0] polygons with same attribute value

• 1 — [1] all polygons

• 2 — [2] polygons with same attribute value (keep inner boundaries)

• 3 — [3] all polygons (keep inner boundaries)

Default: 0

Outputs

Dissolved Polygons

[vector] <put output description here>

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Console usage

processing .

runalg( ’saga:polygondissolve’ , polygons, field_1, field_2, field_3, dissolve, dissolved)

See also

Polygon-line intersection

Description

<put algortithm description here>

Parameters

Polygons

[vector: polygon] <put parameter description here>

Lines

[vector: line] <put parameter description here>

Outputs

Intersection

[vector] <put output description here>

Console usage

processing .

runalg( ’saga:polygonlineintersection’ , polygons, lines, intersect)

See also

Polygon parts to separate polygons

Description

<put algortithm description here>

Parameters

Polygons

[vector: polygon] <put parameter description here>

Ignore Lakes

[boolean] <put parameter description here>

Default: True

Outputs

Polygon Parts

[vector] <put output description here>

Console usage

processing .

runalg( ’saga:polygonpartstoseparatepolygons’ , polygons, lakes, parts)

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See also

Polygon properties

Description

<put algortithm description here>

Parameters

Polygons

[vector: polygon] <put parameter description here>

Number of Parts

[boolean] <put parameter description here>

Default: True

Number of Vertices

[boolean] <put parameter description here>

Default: True

Perimeter

[boolean] <put parameter description here>

Default: True

Area

[boolean] <put parameter description here>

Default: True

Outputs

Polygons with Property Attributes

[vector] <put output description here>

Console usage

processing .

runalg( ’saga:polygonproperties’ , polygons, bparts, bpoints, blength, barea, output)

See also

Polygon shape indices

Description

Calculates spatial statistics for polygons. This includes:

• area

• perimeter

• perimeter / area

• perimeter / square root of the area

• maximum distance

• maximum distance / area

• maximum distance / square root of the area

• shape index

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Parameters

Shapes

[vector: polygon] Layer to analyze.

Outputs

Shape Index

[vector] The resulting layer.

Console usage

processing .

runalg( ’saga:polygonshapeindices’ , shapes, index)

See also

Polygons to edges and nodes

Description

Extracts boundaries and nodes of polygons in separate files.

Parameters

Polygons

[vector: polygon] Input layer.

Outputs

Edges

[vector] Resulting line layer with polygons boundaries.

Nodes

[vector] Resulting line layer with polygons nodes.

Console usage

processing .

runalg( ’saga:polygonstoedgesandnodes’ , polygons, edges, nodes)

.

See also

18.7.18 Shapes tools

Create graticule

Description

Creates a grid.

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Parameters

Extent

[vector: any] Optional.

Grid will be created according to the selected layer.

Output extent

[extent] Extent of the grid.

Default: 0,1,0,1

Division Width

[number] X-axes spacing between the lines.

Default: 1.0

Division Height

[