QGIS User Guide - Documentation
QGIS User Guide
Rilis 2.6
QGIS Project
22 December 2014
Daftar Isi
3
5
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
5
Konvensi Teks atau Papan Ketik
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
5
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
6
7
9
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
9
Jelajahi data dan menyusun peta
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
9
Membuat, menyunting, mengelola dan ekspor data
. . . . . . . . . . . . . . . . . . . . . . . . .
10
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
10
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
10
Memperpanjang fungsionalitas QGIS melalui plugin
. . . . . . . . . . . . . . . . . . . . . . . .
10
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
11
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
12
13
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
13
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
13
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
13
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
14
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
14
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
14
15
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
15
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
15
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
16
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
17
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
17
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
19
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
20
21
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
22
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
27
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
27
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
30
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
30
i
31
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
31
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
31
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
31
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
33
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
35
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
36
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
38
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
39
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
41
43
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
43
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
44
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
44
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
53
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
61
12 Pekerjaan dengan Data Vektor
63
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
63
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
75
12.3 The Vector Properties Dialog
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
79
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 105
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 112
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 129
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 130
13 Pekerjaan dengan Data Raster
133
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 133
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 134
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 142
145
14.1 QGIS sebagai OGC Klien Data
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 145
14.2 QGIS sebagai OGC Data Server
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 154
161
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 161
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 165
171
16.1 Starting the GRASS plugin
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 171
16.2 Loading GRASS raster and vector layers
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 172
16.3 GRASS LOCATION and MAPSET
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 172
16.4 Importing data into a GRASS LOCATION
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 174
16.5 The GRASS vector data model
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 175
16.6 Creating a new GRASS vector layer
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 176
16.7 Digitizing and editing a GRASS vector layer
. . . . . . . . . . . . . . . . . . . . . . . . . . . . 176
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 179
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 179
ii
189
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 189
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 190
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 199
17.4 Antarmuka memproses batch
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 205
17.5 Using processing algorithms from the console
. . . . . . . . . . . . . . . . . . . . . . . . . . . 207
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 212
17.7 Writing new Processing algorithms as python scripts
. . . . . . . . . . . . . . . . . . . . . . . . 213
17.8 Handing data produced by the algorithm
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 215
17.9 Communicating with the user
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 215
17.10 Documenting your scripts
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 216
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 216
17.12 Best practices for writing script algorithms
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 216
17.13 Pre- and post-execution script hooks
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 216
17.14 Configuring external applications
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 217
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 223
18 Processing providers and algorithms
225
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 225
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 258
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 283
18.4 OrfeoToolbox algorithm provider
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 285
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 360
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 414
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 424
18.8 TauDEM algorithm provider
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 595
627
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 628
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 632
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 633
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 655
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 656
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 658
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 660
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 661
663
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 663
20.2 Menggunakan QGIS Plugin Inti
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 667
20.3 Plugin Mengambil Koordinat
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 668
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 668
20.5 Plugin Pengonversi Dxf2Shp
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 669
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 670
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 680
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 683
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 686
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 690
20.11 Plugin Mengedit Diluar Jaringan (Offline)
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 691
20.12 Plugin Spasial Oracle GeoRaster
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 691
20.13 Plugin Raster Analisis Terrain
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 694
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 695
20.15 MetaSearch Catalogue Client
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 699
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 702
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 703
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 705
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 705
20.20 Plugin Pemeriksa Topologi
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 708
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 709
iii
711
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 711
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 712
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 712
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 713
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 713
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 713
715
22.1 GNU General Public License
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 715
22.2 GNU Free Documentation License
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 718
23 Literatur dan Referensi Web
725
727
iv
.
.
QGIS User Guide, Rilis 2.6
Daftar Isi 1
QGIS User Guide, Rilis 2.6
2 Daftar Isi
BAB
1
Pendahuluan
Dokumen ini merupakan buku petunjuk asli dari perangkat lunak yang dijelaskan QGIS. Perangkat lunak dan perangkat keras yang dijelaskan dalam dokumen ini dalam banyak kasus merupakan merek dagang terdaftar dan karena itu tunduk pada persyaratan hukum. QGIS menggunakan Lisensi Publik Umum GNU (GNU General
Public License). Temukan informasi lebih lanjut pada QGIS alamat web http://www.qgis.org
.
Detil, data, hasil dll. pada dokumen ini telah ditulis ulang dan diverifikasi dengan sebaik mungkin pengetahuan dan tanggungjawab dari penulis dan editor. Bagaimanapun juga, dimungkinkan adanya kesalahan pada isi dokumen ini.
Oleh karena itu, semua data tidak bertanggung jawab untuk setiap pekerjaan atau jaminan. Para penulis, editor dan penerbit tidak mengambil tanggung jawab atau kewajiban atas kegagalan dan konsekuensinya. Selalu terbuka bagi Anda untuk menunjukkan kemungkinan kesalahan.
Dokumen ini telah diatur dengan reStructuredText. Ini tersedia sebagai sumber kode reST di github dan dalam jaringan (online) dengan format HTML dan PDF di http://www.qgis.org/en/docs/ . Versi terjemahan dari dokumen ini dapat diunduh dalam beberapa format melalui proyek dokumentasi QGIS. Informasi lebih lanjut tentang kontribusi pada dokumen ini dan tentang menerjemahkannya, silakan kunjungi: http://www.qgis.org/wiki/ .
Tautan pada dokumen ini
Dokumen ini berisi tautan internal dan eksternal. Silakan klik pada tautan internal akan membuka dokumen, sedangkan klik tautan eksternal membuka alamat internet. Dalam bentuk PDF, tautan internal dan eksternal diperlihatkan dengan warna biru dan ditangani oleh sistem peramban web (browser). Dalam bentuk HTML, menampilkan peramban web (browser) dan menangani keduanya secara identik.
Pengguna, Penulis dan Editor Panduan Pemasangan dan Pemrograman (Coding):
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
Martin Dobias
Magnus Homann
Lars Luthman
Marco Hugentobler
Gavin Macaulay Gary E. Sherman
Richard Duivenvoorde Andreas Neumann
Andy Schmid Hien Tran-Quang
Hak Cipta (c) 2004 - 2014 QGIS Tim Pengembang
Internet: http://www.qgis.org
Lisensi dokumen ini
.
Diizinkan untuk menyalin, mendistribusikan dan / atau memodifikasi dokumen ini di bawah syarat-syarat Lisensi
Dokumentasi Bebas GNU (GNU Free Documentation License), atau versi yang lebih baru yang diterbitkan oleh
Free Software Foundation; tanpa Bagian Invarian, tanpa Teks Sampul-Depan, dan tanpa Teks Sampul-Belakang.
Salinan lisensi termasuk dalam Lampiran
GNU Free Documentation License
3
QGIS User Guide, Rilis 2.6
4 Bab 1. Pendahuluan
BAB
2
Konvensi
Bagian ini menjelaskan gaya seragam yang akan digunakan di seluruh manual ini.
2.1 Konvensi GUI
Gaya konvensi GUI dimaksudkan untuk meniru tampilan GUI. Secara umum, gaya akan mencerminkan penampilan non-hover, sehingga pengguna dapat memindai visual GUI untuk menemukan sesuatu yang tampak seperti petunjuk di manual.
• Menu Pilihan: Lapisan
→
Tambah Lapisan Raster atau :menuselection: ‘ Pengaturan –> Toolbar –> Digitalisasi
• Alat:
Tambah Lapisan Raster
• Tombol : [Simpan sebagai Default]
• Kotak Judul: Properti Lapisan
• Tab: Umum
• Kotak Centang: Render
• Tombol Radio: Postgis SRID EPSG ID
• Pilih Nomor:
• Pilih String:
• Lihat Berkas:
• Pilih Warna:
• Slider:
• Masukkan Teks:
Sebuah bayangan menunjukkan komponen GUI yang dapat diklik.
2.2 Konvensi Teks atau Papan Ketik
Panduan ini juga mencakup gaya yang berhubungan dengan teks, perintah papan ketik dan pemrograman (coding) untuk menunjukkan entitas yang berbeda, seperti kelas, atau metode. Gaya ini tidak sesuai dengan penampilan yang sebenarnya dari teks atau coding dalam QGIS.
• Pranala: http://qgis.org
• Kombinasi Keystroke: tekan
Ctrl+B
, artinya tekan dan tahan tombol Ctrl dan tekan tombol B.
5
QGIS User Guide, Rilis 2.6
• Nama Berkas: lakes.shp
• Nama Kelas: LapisanBaru
• Metode: classFactory
• Server: myhost.de
• Teks Pengguna: qgis --help
Baris kode ditunjukkan dengan huruf fixed-width
PROJCS["NAD_1927_Albers",
GEOGCS["GCS_North_American_1927",
2.3 Petunjuk Spesifik Platform
Urutan GUI dan sejumlah kecil teks yang dapat diformat inline: Klik Berkas QGIS
→
Keluar untuk menutup QGIS . Hal ini menunjukkan bahwa di platform Linux, Unix dan Windows, pertama Anda harus mengklik menu Berkas, kemudian Keluar, sementara di platform Macintosh OS X, Anda harus mengklik QGIS menu pertama, kemudian Keluar.
Sejumlah besar teks dapat diformat sebagai daftar:
• Melakukan ini
• Melakukan itu
• Melakukan sesuatu yang lain atau sebagai paragraf:
Lakukan ini dan ini dan ini. Kemudian melakukan ini dan ini dan ini dan ini dan ini dan ini dan ini dan ini dan ini.
Lakukan itu. Kemudian melakukan itu dan itu dan itu dan itu dan itu dan itu dan itu dan itu dan itu dan itu dan itu dan itu dan itu dan itu dan itu.
.
Layar yang muncul di seluruh buku panduan telah dibuat pada platform yang berbeda; platform ditunjukkan dengan ikon-platform tertentu pada akhir gambar keterangan.
6 Bab 2. Konvensi
BAB
3
Kata Pengantar
.
Selamat datang di dunia indah dari Sistem Informasi Geografis (GIS)!
QGIS adalah Sistem Informasi Geografis Sumber Terbuka (Open Source). Proyek ini lahir di bulan Mei 2002 dan didirikan sebagai sebuah proyek di SourceForge pada bulan Juni tahun yang sama. Kami telah bekerja keras membuat perangkat lunak GIS (merupakan perangkat lunak proprietary tradisional mahal) prospek yang layak bagi siapa saja dengan akses dasar ke Personal Komputer. QGIS saat ini berjalan pada kebanyakan platform Unix,
Windows, dan OS X. QGIS dikembangkan menggunakan toolkit Qt ( http://qt.digia.com
) dan C++. Ini berarti bahwa QGIS terasa cepat dan menyenangkan, antarmuka pengguna grafis yang mudah digunakan (GUI).
QGIS bertujuan untuk menjadi GIS yang mudah digunakan, menyediakan fungsi dan fitur-fitur umum. Tujuan awalnya adalah untuk menyediakan penampil data GIS. QGIS telah mencapai titik dalam evolusi di mana ia digunakan sehari-hari oleh banyak orang untuk kebutuhan melihat data GIS mereka. QGIS mendukung sejumlah format data raster dan vektor, dengan dukungan format baru mudah ditambahkan dengan menggunakan arsitektur plugin.
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
Tip: Pembaruan Dokumentasi
Versi terbaru dari dokumen ini selalu dapat ditemukan di website dokumentasi QGIS di http://www.qgis.org/en/docs/
7
QGIS User Guide, Rilis 2.6
8 Bab 3. Kata Pengantar
BAB
4
Fitur-fitur
QGIS menawarkan banyak fungsi GIS umum yang disediakan oleh fitur inti dan plugin. Sebuah ringkasan pendek dari enam kategori umum fitur dan plugin disajikan di bawah ini, diikuti oleh wawasan pertama ke konsol Python yang terintegrasi.
4.1 Lihat data
Anda dapat melihat dan overlay data vektor dan raster dalam format dan proyeksi yang berbeda tanpa konversi ke format internal maupun umum. Format yang didukung termasuk:
• Tabel spasial-enabled dan tampilan menggunakan PostGIS, SpatiaLite dan MSSQL Spasial, Oracle Spasial, format vektor yang didukung oleh perpustakaan OGR, termasuk ESRI shapefile, MapInfo, SDTS, GML dan banyak lagi, lihat bagian
Pekerjaan dengan Data Vektor .
• Format raster dan citra yang didukung dengan terpasangnya GDAL (Geospatial Data Abstraction Library) perpustakaan, seperti GeoTiff, ERDAS IMG, ArcInfo ASCII GRID, JPEG, PNG dan banyak lagi, lihat bagian
Pekerjaan dengan Data Raster .
• Data raster dan vektor GRASS dari basis data GRASS (lokasi/mapset). Lihat bagian
• Data spasial dalam jaringan sebagai Layanan OGC Web, termasuk WMS, WMTS, WCS, WFS, dan WFS-T.
Lihat bagian
4.2 Jelajahi data dan menyusun peta
Anda dapat membuat peta interaktif dan mengeksplorasi data spasial dengan GUI yang ramah. Banyak alat yang tersedia di GUI termasuk:
• QGIS peramban web
• On-the-fly proyeksi ulang
• Pengelola DB
• Penyusun Peta
• Panel Peninjau
• Bookmark spasial
• Annotation tools
• Identifikasi/pilih fitur
• Sunting/lihat/cari atribut
• Fitur pelabelan data-ditentukan
9
QGIS User Guide, Rilis 2.6
• Alat simbologi vektor dan raster data-ditentukan
• Peta komposisi atlas dengan lapisan graticule
• Bar skala panah utara dan label hak cipta untuk peta
• Dukungan menyimpan dan mengembalikan proyek-proyek
4.3 Membuat, menyunting, mengelola dan ekspor data
Anda dapat membuat, mengedit, mengelola dan ekspor lapisan vektor dan raster dalam beberapa format. QGIS menawarkan sebagai berikut:
• Alat Digitalisasi yang didukung format OGR dan lapisan vektor GRASS
• Kemampuan untuk membuat dan mengedit lapisan shapefile dan vektor GRASS
• Plugin Georeferencer ke geocode gambar
• Alat GPS untuk mengimpor dan mengekspor format GPX, dan mengkonversi format GPS lain ke GPX atau unduh/unggah langsung ke unit GPS (di Linux, usb: telah ditambahkan ke daftar perangkat GPS.)
• Dukungan memvisualisasikan dan mengedit data OpenStreetMap
• Kemampuan membuat tabel basis data spasial dari shapefile dengan Plugin Pengelola DB
• Peningkatan penanganan tabel basis data spasial
• Peralatan untuk mengelola tabel atribut vektor
• Opsi menyimpan cuplikan layar sebagai gambar ber-georeferensi.
4.4 Analisis data
Anda dapat melakukan analisis data spasial pada basis data spasial dan format OGR lain yang didukung. QGIS saat ini menawarkan analisis vektor, sampling, geoprocessing, geometri dan aplikasi manajemen basis data. Anda juga dapat menggunakan aplikasi GRASS terintegrasi, yang meliputi fungsi GRASS lengkap lebih dari 400 modul
(lihat bagian
GRASS GIS Integration ). Atau, Anda bekerja dengan Plugin Processing, yang menyediakan kerangka
analisis geospasial yang kuat untuk memanggil algoritma pihak asli dan ketiga dari QGIS, seperti GDAL, SAGA,
GRASS, fTools dan banyak lagi (lihat bagian
4.5 Terbitkan peta di Internet
QGIS dapat digunakan sebagai WMS, WMTS, WMS-C atau WFS dan WFS-T client, dan sebagai WMS, WCS atau WFS server (lihat bagian
Pekerjaan dengan Data OGC .). Selain itu Anda dapat mengekspor data, mempub-
likasikan mereka di internet menggunakan webserver dengan UMN MapServer atau GeoServer yang terpasang.
4.6 Memperpanjang fungsionalitas QGIS melalui plugin
QGIS dapat disesuaikan dengan kebutuhan khusus Anda dengan arsitektur plugin extensible dan perpustakaan yang dapat digunakan untuk membuat plugin. Anda dapat membuat aplikasi baru dengan C++ atau Python!
10 Bab 4. Fitur-fitur
QGIS User Guide, Rilis 2.6
4.6.1 Inti Plugin
Plugin inti termasuk:
1. Rekaman Koordinat (Tetikus merekam koordinat di CRS yang berbeda)
2. DB Manager (Pertukaran, mengedit dan melihat lapisan dan tabel; mengeksekusi query SQL)
3. Diagram Overlay (Menempatkan diagram pada lapisan vektor)
4. Pengkonversi Dxf2Shp (Mengonversi DXF ke Shape)
5. eVIS (Visualize events)
6. fTools (Analisa dan kelola data vektor)
7. GDALTools (Integrasi alat GDAL ke dalam QGIS)
8. Georeferencer GDAL (Menambahkan informasi proyeksi ke raster menggunakan GDAL)
9. Peralatan GPS (Memuat dan impor data GPS)
10. GRASS (GRASS GIS integrasi)
11. Heatmap (Menghasilkan raster heatmap dari data titik)
12. Plugin Interpolasi (interpolasi berdasarkan simpul dari lapisan vektor)
13. Penyuntingan Luar Jaringan (Memungkinkan menyunting luar jaringan dan sinkronisasi dengan basis data)
14. Oracle Spatial GeoRaster
15. Processing (formerly SEXTANTE)
16. Analisis Terrain Raster (Analisis terrain berbasis raster)
17. Plugin Grafik Jalan (Analisis jaringan terpendek)
18. Spatial Query Plugin
19. SPIT (Impor Shapefile ke PostgreSQL/PostGIS)
20. Plugin SQL Anywhere (Menyimpan lapisan vektor dengan basis data SQL Anywhere)
21. Pemeriksa Topologi (Menemukan kesalahan topologi dalam lapisan vektor)
22. Plugin Zonal Statistik (hitung, jumlah, rata-rata raster untuk setiap poligon dari lapisan vektor)
4.6.2 Plugin Eksternal Python
QGIS menawarkan semakin banyak plugin python eksternal yang diberikan oleh masyarakat. Plugin ini berada di repositori resmi plugin, dan dapat dengan mudah dipasang menggunakan Pemasang Plugin Python. Lihat bagian load_external_plugin .
4.7 Python Console
Untuk membuat skrip, memungkinkan untuk mengambil keuntungan dari konsol Python terintegrasi, dimana bisa dibuka dari menu: Plugin
→
Konsol Python . Konsol terbuka sebagai jendela utilitas non-modal. Untuk interaksi dengan lingkungan QGIS, ada variabel qgis.utils.iface
, yang merupakan contoh dari
QgsInterface
.
Antarmuka ini memungkinkan akses ke kanvas peta, menu, toolbar dan bagian lain dari aplikasi QGIS.
Untuk informasi lebih lanjut tentang bekerja dengan plugin dan aplikasi Python Console dan Programming Py|qg|, silakan mengacu ke http://www.qgis.org/html/en/docs/pyqgis_developer_cookbook/index.html
.
4.7. Python Console 11
QGIS User Guide, Rilis 2.6
4.8 Isu yang Diketahui
4.8.1 Jumlah dari batas berkas yang dibuka
Jika Anda membuka sebuah proyek QGIS besar dan Anda yakin bahwa semua lapisan valid, tetapi beberapa lapisan ditandai sebagai lapisan buruk, Anda mungkin dihadapkan dengan masalah ini. Linux (dan OS lain juga) memiliki batas berkas yang dibuka. Batasan sumber daya per-proses dan diturunkan. Perintah ulimit merupakan termina built-in, mengubah batas hanya untuk proses terminal saat ini; batas baru akan diturunkan oleh setiap proses anak.
Anda bisa meliht semua informasi ulimit dengan mengetik [email protected]:~$ ulimit -aS
Anda bisa melihat jumlah yang diperbolehkan saat berkas dibuka per proses dengan perintah berikut di konsol [email protected]:~$ ulimit -Sn
Untuk mengubah batas sesi yang ada
, Anda mungkin dapat menggunakan sesuatu seperti [email protected]:~$ ulimit -Sn #number_of_allowed_open_files [email protected]:~$ ulimit -Sn [email protected]:~$ qgis
Untuk memperbaikinya selamanya
Pada kebanyakan sistem Linux, batasan sumber daya yang ditetapkan pada login dengan modul pam_limits sesuai dengan pengaturan yang terkandung dalam
/etc/security/limits.conf
atau
/etc/security/limits.d/*.conf
. Anda harus dapat mengedit berkas jika Anda memiliki hak istimewa root (juga via sudo), tetapi Anda akan perlu untuk login lagi sebelum perubahan berlaku.
Informasi tambahan:
.
http://www.cyberciti.biz/faq/linux-increase-the-maximum-number-of-open-files/ http://linuxaria.com/article/openfiles-in-linux?lang=en
12 Bab 4. Fitur-fitur
BAB
5
Apa yang baru pada 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 Aplikasi dan Opsi Proyek
• Project filename in properties : You can now see the full path for the QGIS project file in the project properties dialog.
5.2 Penyedia Data
• 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 Penyusun Peta
• 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.
13
QGIS User Guide, Rilis 2.6
5.4 Server QGIS
5.5 Simbologi
.
5.6 Antarmuka Pengguna
14 Bab 5. Apa yang baru pada QGIS 2.6
BAB
6
Memulai
Bab ini memberikan gambaran singkat cara memasang QGIS, beberapa contoh data dari QGIS halaman web dan menjalankan sesi pertama memvisualisasikan lapisan raster dan vektor sederhana.
6.1 Pemasangan (Instalasi)
Pemasangan QGIS sangat sederhana. Standar paket installer tersedia untuk MS Windows dan Mac OS X. Tersedia paket binari GNU/Linux (rpm dan deb) atau repositori perangkat lunak untuk menambah manajer instalasi.
Dapatkan informasi terakhir paket binari pada website QGIS http://download.qgis.org
.
6.1.1 Pemasangan dari sumber
Jika Anda perlu membangun QGIS dari sumber, silakan mengacu petunjuk instalasi. Mereka didistribusikan dengan kode sumber QGIS dalam sebuah berkas yang bernama ‘INSTALL’. Anda juga bisa menemukannya di dalam jaringan (online) di http://htmlpreview.github.io/?https://raw.github.com/qgis/QGIS/master/doc/INSTALL.html
6.1.2 Pemasangan pada media eksternal
QGIS memungkinkan Anda untuk menentukan opsi
--configpath yang menimpa path standar untuk konfigurasi pengguna (misalnya,
~/.qgis2
Linux) dan kemampuan QSettings menggunakan direktori ini juga. Hal ini memungkinkan Anda juga, membawa pemasang QGIS dalam pada flash drive bersama dengan semua plugin dan pengaturan. Lihat Bagian
untuk informasi tambahan.
6.2 Contoh data
Panduan pengguna berisi contoh-contoh berdasarkan contoh dataset QGIS.
installer Windows memiliki pilihan untuk mengunduh contoh dataset QGIS. Jika dicentang, data akan diunduh ke folder
My Documents
Anda dan ditempatkan dalam folder bernama
GIS database
. Anda dapat menggunakan Windows Explorer untuk memindahkan folder ini ke setiap lokasi yang nyaman. Jika Anda tidak memilih kotak centang untuk memasang contoh dataset selama instalasi QGIS, Anda dapat melakukan salah satu dari berikut:
• Gunakan data GIS yang Anda miliki
• Unduh contoh data dari http://download.osgeo.org/qgis/data/qgis_sample_data.zip
• Hapus (uninstall) QGIS dan pasang ulang dengan opsi unduh data, (hanya direkomendasikan jika solusi di atas tidak berhasil)
15
QGIS User Guide, Rilis 2.6
Untuk GNU/Linux dan Mac OS X, belum ada paket instalasi dataset yang tersedia rpm, deb atau dmg.
Untuk menggunakan contoh dataset unduh berkas ZIP arsip qgis_sample_data dari http://download.osgeo.org/qgis/data/qgis_sample_data.zip
dan unzip arsip pada sistem Anda.
Dataset Alaska mencakup semua data GIS yang digunakan sebagai contoh dan cuplikan layar di buku panduan; dan termasuk basis data kecil GRASS. Proyeksi contoh dataset QGIS adalah Alaska Albers Equal Area dengan satuan kaki. Kode EPSG 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
]]
Jika Anda berniat untuk menggunakan QGIS sebagai grafis frontend GRASS, Anda dapat menemukan pilihan contoh lokasi (misalnya Spearfish atau South Dakota) di situs resmi GRASS GIS http://grass.osgeo.org/download/sample-data/ .
6.3 Sesi Contoh
Sekarang QGIS Anda sudah terpasang dan contoh dataset tersedia, kami ingin menunjukkan sesi contoh QGIS singkat dan sederhana. Kami akan memvisualisasikan lapisan (layer) raster dan vektor. Kami akan menggunakan lapisan (layer) raster tutupan lahan qgis_sample_data/raster/landcover.img
dan lapisan (layer) vektor danau qgis_sample_data/gml/lakes.gml
.
6.3.1 Mulai QGIS
• Mulai QGIS dengan mengetik: “QGIS” di terminal, atau menggunakan bineri precompiled, menggunakan menu Aplikasi.
• Mulai QGIS menggunakan menu Start atau shortcut desktop, atau dobel klik di berkas proyek QGIS.
• Dobel klik ikon pada folder Aplikasi.
6.3.2 Muat lapisan (layer) raster dan vektor dari contoh dataset
16
1. Klik di ikon
Load Raster
2. Jelejahi folder qgis_sample_data/raster/
, pilih berkas ERDAS Img landcover.img
dan klik
[Buka] .
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)”.
Bab 6. Memulai
QGIS User Guide, Rilis 2.6
4. Sekarang klik di ikon
Load Vector
.
5.
Berkas harus dipilih sebagai Jenis Sumber Tipe Sumber dalam dialog baru Tambah lapisan vektor .
Sekarang klik [Jelajah] untuk memilih lapisan vektor.
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. Perbesar sedikit ke daerah favorit Anda dengan beberapa danau.
8. Dobel klik lapisan (layer) lakes di legenda peta untuk membuka dialog Properti .
9. Klik pada tab Gaya dan pilih biru sebagai warna.
10. Klik tab Label dan centang kotak centang kolom “NAMES” sebagai kolom isian label.
Label lapisan ini dengan untuk mengaktifkan pelabelan. Pilih
11. Untuk memudahkan pembacaan label, Anda dapat menambahkan penyangga (buffer) putih di sekitar mereka, dengan klik “Buffer” dalam daftar sebelah kiri, periksa penyangga (buffer).
Draw text buffer dan pilih 3 sebagai ukuran
12. Klik [Terapkan] . Periksa apakah hasilnya baik, dan terakhir klik [OK] .
Anda dapat melihat betapa mudahnya untuk memvisualisasikan lapisan (layer) raster dan vektor dalam QGIS.
Mari kita lanjutkan ke bagian berikut untuk mempelajari lebih lanjut tentang fungsi, fitur dan pengaturan yang tersedia dan bagaimana menggunakannya.
6.4 Memulai dan Menghentikan QGIS
Dalam bagian
Anda sudah belajar bagaimana memulai QGIS. Kami akan mengulanginya di sini dan
Anda akan melihat QGIS juga menyediakan opsi baris perintah lebih lanjut.
• Dengan asumsi bahwa QGIS dipasang di PATH, Anda dapat memulai QGIS dengan mengetik: qgis pada terminal atau dengan mengklik dobel pada link aplikasi QGIS (atau shortcut) pada desktop atau dalam menu aplikasi.
• Mulai QGIS menggunakan menu Start atau shortcut desktop, atau dobel klik di berkas proyek QGIS.
• Dobel klik ikon di folder Aplikasi Anda.
Jika Anda memulai QGIS di terminal, jalankan
/path-to-installation-executable/Contents/MacOS/Qgis .
Untuk menghentikan QGIS, klik menu opsi
Ctrl+Q
.
Berkas QGIS
→
Keluar , atau menggunakan shortcut
6.5 Pilihan Baris Perintah
QGIS mendukung sejumlah pilihan ketika dimulai dari baris perintah. Untuk mendapatkan daftar opsi, enter qgis --help pada baris perintah. Pernyataan penggunaan untuk QGIS adalah: 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
6.4. Memulai dan Menghentikan QGIS 17
QGIS User Guide, Rilis 2.6
[--lang language] use language for interface text
[--project projectfile] load the given QGIS project
[--extent xmin,ymin,xmax,ymax] set initial map extent
[--nologo]
[--noplugins] hide splash screen don’t restore plugins on startup
[--nocustomization] don’t apply GUI customization
[--customizationfile]
[--optionspath path] use the given ini file as GUI customization use the given QSettings path
[--configpath path]
[--code path] use the given path for all user configuration run the given python file on load
[--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
Tip: Contoh Menggunakan argumen baris perintah
Anda dapat memulai QGIS dengan menentukan satu atau lebih berkas data pada baris perintah. Misalnya, dengan asumsi Anda berada di direktori qgis_sample_data
, Anda bisa memulai QGIS dengan berkas lapisan vektor dan raster yang diatur untuk dimuat pada startup dengan menggunakan perintah berikut: qgis
./raster/landcover.img ./gml/lakes.gml
Pilihan baris perintah
--snapshot
Pilihan ini memungkinkan Anda untuk membuat cuplikan layar dalam format PNG dari tampilan saat ini. Hal ini sangat berguna ketika Anda memiliki banyak proyek dan ingin menghasilkan cuplikan layar dari data Anda.
Saat ini menghasilkan berkas PNG dengan piksel 800x600. Hal ini dapat diadaptasi dengan menggunakan argumen baris perintah
--width dan
--height
. Nama berkas bisa ditambahkan setelah
--snapshot
.
Pilihan baris perintah
--lang
Berdasarkan lokal QGIS Anda, pilih lokalisasi yang benar. Jika Anda ingin mengubah bahasa, Anda dapat menentukan kode bahasa. Sebagai contoh: --lang=id QGIS dimulai menggunakan lokal Indonesia. Daftar bahasa saat ini yang didukung dengan kode bahasa dan status disediakan di http://hub.qgis.org/wiki/quantumgis/GUI_Translation_Progress .
Baris perintah
--project
Memulai QGIS dengan berkas proyek yang sudah ada. Hanya tambahkan baris perintah
--project ikuti nama berkas proyek yang akan dibuka dan QGIS akan membukanya dengan memuat semua lapisan (layer).
Baris perintah
--extent
Untuk memulai dengan peta batas tertentu menggunakan opsi ini. Anda perlu menambahkan kotak bounding sejauh Anda dalam urutan dipisahkan oleh koma:
--extent xmin,ymin,xmax,ymax
Baris perintah
--nologo
Argumen baris perintah ini menyembunyikan layar splash ketika Anda mulai QGIS.
Baris perintah
--noplugins
Jika Anda mengalami kesulitan pada saat startup dengan plugin, Anda dapat menghindari beban mereka pada saat startup dengan opsi ini. Mereka masih akan tersedia di Manajer Plugin after-wards.
Baris perintah --nocustomization
18 Bab 6. Memulai
QGIS User Guide, Rilis 2.6
Menggunakan argumen baris perintah ini, Anda bisa menentukan penyesuaian berkas GUI, yang akan digunakan saat startup.
Baris perintah
--nocustomization
Menggunakan argumen baris perintah ini, penyesuaian GUI yang ada tidak akan diterapkan pada saat startup.
Baris perintah
--optionspath
You can have multiple configurations and decide which one to use when starting QGIS with this option. See
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:
--optionspath /path/to/config/
Baris perintah
--configpath
Pilihan ini mirip dengan yang di atas, tapi selanjutnya menimpa path default untuk konfigurasi pengguna
(
~/.qgis2
) dan kemampuan QSettings untuk menggunakan direktori ini juga. Hal ini memungkinkan pengguna mis membawa instalasi QGIS pada flash drive bersama dengan semua plugin dan pengaturan.
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 Proyek
Sesi QGIS Anda dianggap sebagai sebuah proyek. QGIS bekerja pada satu proyek pada satu waktu. Pengaturan yang baik dianggap sebagai per-proyek, atau sebagai default untuk proyek-proyek baru (lihat Bagian
bisa menyimpan kerja Anda ke dalam sebuah berkas proyek dengan menggunakan pilihan menu
Proyek
→
Simpan atau Proyek
→
Simpan Sebagai .
Memuat proyek tersimpan ke dalam sesi QGIS menggunakan Proyek
→ plate atau
Proyek
→
Buka yang baru teradi
→
.
Buka ...
, Proyek
→
Baru dari tem-
Jika Anda ingin membersihkan sesi Anda dan memulai baru lagi, pilih
Proyek
→
Baru
. Pilihan menu ini akan meminta Anda untuk menyimpan proyek yang telah ada jika perubahan yang telah dibuat sejak dibuka atau yang terakhir disimpan.
Jenis-jenis informasi yang disimpan dalam berkas proyek meliputi:
• Lapisan (layer) yang ditambahkan
• Properti lapisan (layer), termasuk simbolisasi
• Proyeksi untuk tampilan peta
• Tampilan terkahir
6.6. Proyek 19
QGIS User Guide, Rilis 2.6
Berkas proyek disimpan dalam format XML, sehingga memungkinkan untuk mengedit berkas diluar QGIS jika
Anda tahu apa yang Anda lakukan. Format berkas telah diperbaharui beberapa kali dibanding versi QGIS sebelumnya. Berkas proyek dari versi QGIS yang lebih tua mungkin tidak bekerja dengan baik lagi. Harus dibuat sadar akan hal ini, di tab Umum Pengaturan
→
Opsi Anda dapat memilih:
• Prompt untuk menyimpan proyek dan perubahan sumber data bila diperlukan
• Peringatkan ketika membuka berkas proyek QGIS yang disimpan dengan versi lama
Setiap kali Anda menyimpan proyek dalam QGIS 2.2 sekarang berkas cadangan dari proyek dibuat.
6.7 Keluaran (Output)
.
Ada beberapa cara untuk menghasilkan keluaran (output) dari sesi QGIS Anda. Kita telah membahasnya pada
Bagian
Proyek , menyimpan berkas proyek. Berikut ini adalah contoh cara lain untuk menghasilkan keluaran
(output) berkas:
• Menu opsi
Proyek
→
Simpan sebagai Gambar membuka dialog berkas di mana Anda memilih nama, path dan jenis gambar (format PNG atau JPG). Sebuah berkas dengan ekstensi PNGW atau JPGW disimpan dalam folder sama dengan gambar yang mempunyai georeferensi.
• Menu opsi Proyek
→
Ekspor DXF ...
membuka dialog di mana Anda dapat menentukan ‘Symbology mode’,
‘Symbology scale’ dan lapisan vektor yang ingin Anda ekspor ke DXF.
• Menu opsi Proyek
→
Penyusun Cetak Baru membuka dialog di mana Anda dapat me-layout dan mencetak kanvas peta saat ini (lihat Bagian
20 Bab 6. Memulai
BAB
7
QGIS GUI
Ketika QGIS dimulai, Anda akan disajikan tampilan GUI seperti gambar (nomer 1 sampai 5 dalam lingkaran kuning mengacu pada 5 area utama antarmuka yang dibahas dibawah ini).
Gambar 7.1: GUI QGIS dengan contoh data Alaska
Catatan: Jendela dekorasi Anda (judul bar , dll) dapat terlihat berbeda tergantung pada sistem operasi dan window manager Anda .
GUI QGIS dibagi dalam lima area:
1. Bar Menu
2. Bar Tool
3. Legenda Peta
4. Tampilan Peta
5. Status Bar
Kelima komponen antarmuka QGIS dijelaskan secara lebih rinci dalam bagian berikut. Lebih dari dua bagian dijelaskan di shortcut papan ketik dan bantuan.
21
QGIS User Guide, Rilis 2.6
7.1 Bar Menu
Menu bar memberikan akses ke berbagai fitur QGIS menggunakan standar hirarki menu. Menu-menu utama dan ringkasan dari beberapa menu pilihan yang tercantum di bawah ini, bersama-sama dengan ikon dari alat yang sesuai seperti yang ditampilkan pada toolbar, seperti shortcut papan ketik. Shortcut papan ketik juga dapat dikonfigurasi secara manual menggunakan dialog Configure shortcuts , dibuka dari Pengaturan
→
Konfigurasi
Shortcut...
.
Meskipun sebagian besar pilihan menu memiliki alat yang sesuai dan sebaliknya, menu tidak terorganisir seperti toolbar. Toolbar yang berisi alat ini bisa terdaftar setelah setiap pilihan menu diisi pada kotak centang. Beberapa pilihan menu hanya muncul jika plugin yang sesuai dimuat. Untuk informasi lebih lanjut tentang alat dan toolbar, lihat Bagian
7.1.1 Proyek
Pilihan Menu
Baru
Buka
Baru dari template
→
Buka terkahir dikerjakan
→
Simpan
Simpan Sebagai...
Simpan sebagai gambar...
Ekspor DXF ...
Penyusun cetak baru
Manajer Penyusun ...
Penyusun Cetak
→
Keluar QGIS
Shortcut
Ctrl+N
Ctrl+P
Referensi lihat
Ctrl+O lihat
lihat
lihat
lihat
Ctrl+S
Ctrl+Shift+S lihat
lihat
lihat
lihat
lihat
lihat
Ctrl+Q
Toolbar
Proyek
Proyek
Proyek
Proyek
Proyek
Proyek
Proyek
22 Bab 7. QGIS GUI
QGIS User Guide, Rilis 2.6
7.1.2 Edit
Pilihan Menu
Kembali
Ulangi
Ambil Fitur
Salin Fitur
Tempel Fitur
Sisip fitur sebagai
→
Tambah Fitur
Pindah Fitur
Hapus yand dipilih
Rotasi Fitur
Sederhanakan Fitur
Tambah Ring
Tambah Bagian
Isi Ring
Hapus Ring
Hapus bagian
Bentuk Ulang Fitur
Offset Curves
Pisah Fitur
Bagian dipisah
Gabung Fitur Terpilih
Gabung Attr. Fitur Terpilih
Node Tool
Rotasi Simbol Titik
Shortcut Referensi lihat
Ctrl+Z
Ctrl+Shift+Z lihat
Ctrl+X lihat
Ctrl+C
Ctrl+V lihat
lihat
lihat
Working with the Attribute Table
Ctrl+.
lihat
lihat
lihat
lihat
Toolbar
Digitalisasi Lanjutan
Digitalisasi Lanjutan
Digitalisasi
Digitalisasi
Digitalisasi
Digitalisasi
Digitalisasi
Digitalisasi
Digitalisasi Lanjutan lihat
Digitalisasi Lanjutan lihat
lihat
lihat
lihat
lihat
lihat
lihat
lihat
lihat
lihat
lihat
lihat
lihat
Digitalisasi Lanjutan
Digitalisasi Lanjutan
Digitalisasi Lanjutan
Digitalisasi Lanjutan
Digitalisasi Lanjutan
Digitalisasi Lanjutan
Digitalisasi Lanjutan
Digitalisasi Lanjutan
Digitalisasi Lanjutan
Digitalisasi Lanjutan
Digitalisasi Lanjutan
Digitalisasi
Digitalisasi Lanjutan
Setelah mengaktifkan mode
Toggle mengedit untuk lapisan (layer), Anda menemukan ikon
Add Feature di menu Edit tergantung pada jenis lapisan (titik, garis atau poligon).
7.1.3 Edit (ekstra)
Pilihan Menu
Tambah Fitur
Tambah Fitur
Tambah Fitur
Shortcut Referensi Toolbar lihat
Digitalisasi lihat
Digitalisasi lihat
Digitalisasi
7.1. Bar Menu 23
QGIS User Guide, Rilis 2.6
7.1.4 Tampilan
Pilihan Menu
Pan Peta
Geser Peta untuk Menyeleksi
Perbesar
Perkecil
Pilih
→
Identifikasi Fitur
Mengukur
→
Perbesar semua
Perbesar ke lapisan
Perbesar yang diseleksi
Perbesaran Terakhir
Perbesar Selanjutnya
Perbesar Ukuran Aktual
Dekorasi
→
Informasi Peta
Bookmark Baru
Lihat Bookmarks
Refresh
Shortcut
Ctrl++
Ctrl+-
Ctrl+Shift+I kbd: Ctrl+Shift+F
Ctrl+J
Ctrl+B lihat
Ctrl+Shift+B lihat
Ctrl+R
Referensi Toolbar
Navigasi Peta
Navigasi Peta
Navigasi Peta
Navigasi Peta lihat
Atribut lihat
Atribut
Atribut
Navigasi Peta
Navigasi Peta
Navigasi Peta
Navigasi Peta
Navigasi Peta
Navigasi Peta lihat
Atribut
Atribut
Atribut
Navigasi Peta
7.1.5 Lapisan
Pilihan Menu
Baru
→
Lekatkan Lapisan dan Grup ...
Tambah Lapisan Vektor
Tambahkan Lapisan Raster
Tambah Lapisan PostGIS
Tambahkan Lapisan SpatiaLite
Tambah Lapisan WFS
Tambahkan Lapisan Delimited Teks
Gaya Salin
Gaya Tempel
Shortcut Referensi lihat
lihat
kbd: Ctrl+Shift+V lihat
Ctrl+Shift+R lihat
Ctrl+Shift+D lihat
Ctrl+Shift+L lihat
Toolbar
Kelola Lapisan
Kelola Lapisan
Kelola Lapisan
Kelola Lapisan
Kelola Lapisan
Tambahkan Lapisan MSSQL Spasial
Ctrl+Shift+M lihat
Tambah Lapisan Oracle GeoRaster lihat
Plugin Spasial Oracle GeoRaster
Kelola Lapisan
Kelola Lapisan
Tambah Lapisan SQL Anywhere
Tambah Lapisan WMS/WMTS
Tambah Lapisan WCS
Lihat
Ctrl+Shift+W lihat
lihat
Kelola Lapisan
Kelola Lapisan
Kelola Lapisan lihat
see
lihat
lihat
Kelola Lapisan
Kelola Lapisan
Lanjut ke halaman berikutnya
24 Bab 7. QGIS GUI
QGIS User Guide, Rilis 2.6
Pilihan Menu
Buka Tabel Atribut
Toggle Mengedit
Simpan Lapisan diedit
Diedit Sekarang
→
Simpan Sebagai...
Simpan terpilih sebagai berkas vektor...
Tabel 7.1 – lanjutan dari halaman sebelumnya
Shortcut Referensi Toolbar lihat
Working with the Attribute Table
Atribut lihat
lihat
lihat
Digitalisasi
Digitalisasi
Digitalisasi
Lihat
Working with the Attribute Table
Ctrl+D Buang Lapisan
Lapisan Duplikat
Atur CRS Lapisan
Atur CRS proyek dari Lapisan
Properti
Query...
Pelabelan
Tambahkan ke Overview
Tambahkan Semua ke Overview
Ctrl+Shift+C
Ctrl+Shift+O Kelola Lapisan
Menghapus Semua dari Overview
Lihat Semua Lapisan
Sembunyikan Semua Lapisan
Ctrl+Shift+U
Ctrl+Shift+H
Kelola Lapisan
Kelola Lapisan
7.1.6 Pengaturan
Pilihan Menu
Panel
→
Toolbar
→
Shortcut
Toggle Mode Layar Penuh F 11
Proyek Properti ...
Referensi
Lihat
Lihat
Ctrl+Shift+P lihat
Ubah CRS ...
Pengelola Gaya...
Konfigurasi shortcut ...
Kustomisasi ...
Opsi ...
Opsi Snapping ...
lihat
Custom Coordinate Reference System
lihat
lihat lihat
Toolbar
7.1.7 Plugin
Pilihan Menu Shortcut Referensi
Kelola dan Pasang Plugin
Konsol Python lihat
Saat memulai QGIS untuk pertama kali tidak semua inti plugin dimuat.
Toolbar
7.1. Bar Menu 25
QGIS User Guide, Rilis 2.6
7.1.8 Vektor
Pilihan Menu
Open Street Map
→
Peralatan Analisis
→
Peralatan Riset
→
Peralatan Geoprocessing
→
Shortcut Referensi lihat lihat lihat lihat
Peralatan Geometri
→ lihat
Peralatan Manajemen Data
→ lihat
Saat memulai QGIS untuk pertama kali tidak semua inti plugin dimuat.
Toolbar
7.1.9 Raster
Pilihan Menu
Kalkulator Raster ...
Shortcut Referensi lihat
Toolbar
Saat memulai QGIS untuk pertama kali tidak semua inti plugin dimuat.
7.1.10 Pengolahan
Pilihan Menu
Toolbox
Grafis Modeler
Shortcut Referensi lihat
lihat
Sejarah dan log
Opsi dan Konfigurasi
Penampil hasil lihat
lihat
Configuring the processing framework
lihat
Configuring external applications
Perintah
Ctrl+Alt+M lihat
Saat memulai QGIS untuk pertama kali tidak semua inti plugin dimuat.
Toolbar
7.1.11 Bantuan
Pilihan Menu
Konten Bantuan
Apakah ini?
Dokumentasi API
Butuh dukungan komersial?
Beranda QGIS
Periksa versi QGIS
Tentang
Sponsor QGIS
Shortcut
F1
Shift+F1
Ctrl+H
Referensi Toolbar
Bantuan
Bantuan
Harap dicatat bahwa untuk Linux item Menu Bar yang tercantum di atas adalah yang standar di window manager KDE. Di GNOME, menu Pengaturan memiliki isi yang berbeda dan item bisa ditemukan di sini:
26 Bab 7. QGIS GUI
QGIS User Guide, Rilis 2.6
Properti Proyek
Opsi
Konfigurasi Shortcuts
Pengelola Gaya
Proyek
Edit
Edit
Edit
Modifikasi CRS
Panel
→
Toolbar
→
Edit
Tampilan
Tampilan
Toggle Mode Layar Penuh Tampilan
Slider Skala Tile
Pelacakan GPS
Tampilan
Tampilan
7.2 Toolbar
Toolbar menyediakan akses ke sebagian besar fungsi yang sama seperti menu, ditambah alat tambahan untuk berinteraksi dengan peta. Setiap item toolbar memiliki popup bantuan yang tersedia. Tahan tetikus anda ke atas item dan deskripsi singkat mengenai tujuan alat itu akan ditampilkan.
Setiap menubar dipindah kesekitarnya sesuai dengan kebutuhan Anda. Selain itu setiap menubar dapat dimatikan menggunakan tombol kanan tetikus pada menu konteks Anda, arahkan tetikus ke toolbar (baca juga
Tip:
Mengembalikan toolbar
Jika Anda tidak sengaja telah menyembunyikan semua toolbar Anda, Anda dapat mengembalikannya dengan memilih menu opsi Pengaturan
→
Toolbar
→
.
Jika toolbar menghilang di bawah
OS Windows, tampaknya menjadi masalah di QGIS dari waktu ke waktu, Anda harus menghapus
\HKEY_CURRENT_USER\Software\QGIS\qgis\UI\state di registry. Ketika Anda hidupkan ulang
QGIS, kuncinya ditulis lagi secara standar, dan semua toolbar terlihat kembali.
7.3 Legenda Peta
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
Suatu lapisan (layer) dapat dipilih dan digeser ke atas atau kebawah pada legenda menjadi Z-urutan. Z-urutan berarti bahwa lapisan yang terdaftar di bagian atas legenda digambar lapisan bawahnya tercantum dalam legenda.
Catatan: Perilaku ini dapat diganti dengan panel ‘urutan lapisan’.
Lapisan di jendela legenda dapat dikelompokkan dalam grup. Ada dua cara untuk melakukannya:
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. Pilih beberapa lapisan (layer), klik kanan pada jendela legenda dan pilih Grup Terpilih . Lapisan-lapisan yang dipilih secara otomatis akan menjadi satu grup baru.
7.2. Toolbar 27
QGIS User Guide, Rilis 2.6
Untuk mengeluarkan lapisan dari grup, Anda bisa menggesernya keluar, atau klik kanan dan pilih Ubah jadi tingkat teratas . Grup dapat masuk kedalam grup lain.
Kotak centang grup akan memunculkan atau menyembunyikan lapisan dalam grup dengan satu klik.
Isi dari konteks menu tombol kanan tetikus tergantung pada item legenda yang dipilih lapisan (layer) raster atau vektor. Untuk lapisan vektor GRASS
Toggle mengedit tidak tersedia. Lihat bagian
Digitizing and editing a GRASS vector layer
untuk informasi menyunting lapisan (layer) vektor GRASS.
Tombol kanan tetikus untuk lapisan raster
•
Perbesar lapisan extent
• Tampilkan di overview
• Perbesar Skala Terbaik (100%)
• Peregangan Menggunakan Luas Terkini
• Buang
• Duplikat
• Set Layer Scale Visibility
• Atur CRS Lapisan
• Atur CRS Proyek dari Lapisan
• Simpan sebagai ...
•
Save As Layer Definition Style
• Properti
• Ubah Nama
• Gaya Salin
Selain itu, menurut posisi dan seleksi lapisan (layer)
• Ubah jadi item tingkat teratas
• Grup dipilih
Tombol kanan tetikus menu untuk lapisan vektor
• Perbesar ke Lapisan Extent
• Tampilkan di Overview
•
Buang
• Duplikat
• Set Layer Scale Visibility
• Atur CRS Lapisan
• Atur CRS Proyek dari Lapisan
• Buka Tabel Atribut
• Toggle Mengedit (tidak tersedia untuk Lapisan GRASS)
• Simpan Sebagai ...
• Save As Layer Definition Style
•
Saring
•
Tampilkan Fitur Hitung
• Properti
• Ubah Nama
28 Bab 7. QGIS GUI
QGIS User Guide, Rilis 2.6
• Gaya Salin
Selain itu, menurut posisi dan seleksi lapisan (layer)
• Ubah jadi item tingkat teratas
• Grup dipilih
Tombol kanan tetikus menu untuk grup lapisan
• Perbesar ke Grup
• Buang
• Atur Grup CRS
• Ubah Nama
• Add Group
Saat ini memungkinkan memilih lebih dari satu lapisan atau grup pada waktu yang sama dengan menekan tombol
Ctrl sambil memilih lapisan dengan tombol kiri tetikus. Kemudian Anda dapat memindah semua lapisan terpilih ke dalam grup baru pada waktu yang sama.
Anda juga dapat menghapus lebih dari satu Lapisan atau Grup sekaligus dengan memilih beberapa Lapisan (layer) dengan menekan tombol Ctrl dan setelah itu Ctrl+D . Dengan cara ini semua Lapisan atau Grup terpilih akan dibuang dari daftar lapisan.
7.3.1 Bekerja dengan Legenda urutan lapisan tersendiri
Terdapat widget yang memungkinkan untuk mendefinisikan urutan legenda gambar independen. Anda dapat mengaktifkannya dari menu Pengaturan
→
Panel
→
Urutan Lapisan . Di sini menentukan urutan gambar dari lapisan dalam tampilan peta. Melakukan hal ini memungkinkan untuk mengurutkan lapisan Anda dalam urutan kepentingan, sebagai contoh, tapi masih menampilkan mereka dalam urutan yang benar (lihat
Mengaktifkan kotak perilaku standar.
Kontrol urutan rendering bawah daftar lapisan akan menyebabkan kembali ke suatu
7.3. Legenda Peta
Gambar 7.2: Mendefiniskan legenda urutan lapisan tersendiri
29
QGIS User Guide, Rilis 2.6
7.4 Tampilan Peta
Ini “business end” dari QGIS - peta tampil di area ini! Peta yang ditampilkan dalam jendela ini tergantung pada lapisan vektor dan raster yang telah Anda pilih (lihat bagian informasi lebih lanjut tentang cara untuk memuat lapisan). Tampilan peta dapat digeser (mengalihkan fokus tampilan peta untuk daerah lain) dan memperbesar atau memperkecilnya. Berbagai operasi lainnya dapat dilakukan pada peta seperti yang dijelaskan dalam deskripsi toolbar di atas. Tampilan peta dan legenda terikat erat satu sama lain - peta dalam tampilan mencerminkan perubahan yang Anda buat di daerah legenda.
Tip: Perbesar peta dengan tetikus
Anda dapat menggunakan tetikus untuk memperbesar dan memperkecil peta. Tempatkan kursor tetikus di dalam area peta dan roll roda depan (jauh dari Anda) untuk memperbesar dan belakang (ke arah Anda) untuk memperkecil. Posisi kursor tetikus adalah pusat di mana perubahan terjadi. Anda dapat menyesuaikan perilaku pembesaran roda tetikus menggunakan menu Alat Peta dalam menu Pengaturan
→
Opsi.
Tip: Menggeser peta dengan tombol panah dan spasi bar
Anda dapat menggunakan tombol panah untuk menggeser peta. empatkan kursor tetikus dalam area peta dan klik panah kanan untuk menggeser ke Timur, panah kiri untuk menggeser ke Barat, panah atas untuk menggeser ke
Utara dan pana bawah untuk menggeser ke Selatan. Anda juga dapat menggeser peta dengan menggunakan bar spasi atau klik pada tetikus: hanya menggerakkan tetikus bersamaan menekan bar spasi atau klik tetikus.
7.5 Status Bar
.
Bar status melihatkan posisi kursor Anda dalam koordinat peta (misal meter atau derajat desimal) sesuai dengan titik kursor tetikus bergerak pada tampilan peta. Di sebelah kiri tampilan koordinat di bar status adalah tombol kecil yang akan beralih antara menampilkan posisi koordinat atau menampilkan luasan peta saat Anda menggeser dan memperbesar/memperkecil tampilan peta.
Sebelah tampilan koordinat Anda menemukan tampilan skala. Itu menunjukkan skala dari tampilan peta. Jika
Anda memperbesar atau memperkecil QGIS berisi skala saat ini. Ada pemilih skala yang memungkinkan Anda untuk memilih skala standar dari 1:500 sampai 1:1000000.
Suatu perkembangan (progres) bar di status bar menunjukkan kemajuan (progres) render karena setiap lapisan yang diubah di tampilan peta. Dalam beberapa kasus, seperti pengumpulan statistik di lapisan raster, progress bar akan menunjukkan status panjangnya operasi.
Jika ada plugin baru atau pembaruan plugin tersedia, Anda akan melihat pesan sebelah kiri dari bar status. Di sisi kanan status bar adalah kotak centang kecil yang dapat digunakan untuk lapisan sementara yang diberikan ke tampilan peta (lihat Bagian
menghentikan proses rendering peta sekarang.
Sebelah kanan dari fungsi render, Anda akan menemukan kode EPSG dari CRS proyek sekarang dan ikon proyektor. Mengklik ini akan membuka properti proyeksi untuk proyek saat ini.
Tip: Menghitung skala koreksi dari kanvas peta Anda
Saat Anda memulai QGIS, derajat merupakan unit standar, dan QGIS memberitahu bahwa setiap koordinat pada lapisan Anda dalam derajat. Untuk mengubah nilai skala, Anda juga dapat mengubahnya ke satuan meter secara manual di tab Umum dalam Pengaturan
→
Proyek Properti atau Anda bisa memilih Coordinate Reference System
(CRS) proyek dengan klik ikon
CRS status di bagian kanan bawah dari status bar. Dalam kasus terakhir, unit ditetapkan untuk menentukan proyeksi proyek, (misalnya ‘+unit=m’).
30 Bab 7. QGIS GUI
BAB
8
Peralatan Umum
8.1 Shortcut Papanketik
QGIS menyediakan standar shortcut papan ketik untuk banyak fitur. Anda menemukannya di Bagian
Selain itu di menu opsi Pengaturan
→
Konfigurasi Shortcut memungkinkan merubah standar shortcut papanketik dan menambah shortcut papanketik baru ke fitur QGIS.
Gambar 8.1: Tentukan pilihan shortcut (Gnome)
Konfigurasi sederhana. Hanya pilih fitur dari daftar dan klik pada
[Ubah]
,
[Atur none] atau
[Atur Standar]
.
Setelah Anda telah menemukan konfigurasi, Anda dapat menyimpannya sebagai berkas XML dan muat pada instalasi QGIS lain.
8.2 Konteks Bantuan
Saat Anda membutuhkan bantuan dengan topik yang spesifik, Anda dapat mengakses konteks bantuan melalui tombol
[Bantuan] tersedia disebagian besar dialog - harap dicatat bahwa plugin pihak ketiga dapat mengarah ke halaman web khusus.
8.3 Rendering
Secara standar, QGIS membuat semua lapisan terlihat setiap kali kanvas peta di-refresh. Peristiwa yang memicu refresh kanvas peta meliputi:
• Menambahkan lapisan (layer)
31
QGIS User Guide, Rilis 2.6
• Menggeser atau memperbesar
• Mengukur jendela QGIS
• Merubah visitabilitas dari lapisan (layer)
QGIS memungkinkan Anda mengontrol proses rendering dalam beberapa cara.
8.3.1 Scale Dependent Rendering
Skala render memungkinkan Anda untuk menentukan skaa minimum dan skala maksimum di mana lapisan akan terlihat. Untuk mengatur skala render bergantung, buka dialog Properti dengan mengklik-dobel pada lapisan di legenda. Pada tab Umum klik pada kotak centang kemudian atur nilai maskimum dan minimum skala.
Skala bergantung pada visibilitas untuk mengaktifkan fitur,
Anda dapat menentukan nilai skala dengan terlebih dahulu perbesar ke tingkat yang ingin Anda gunakan dan mencatat nilai skala pada status bar QGIS.
8.3.2 Mengontrol Rendering Peta
Me-render peta dapat dikontrol dalam berbagai cara, seperti yang dijelaskan di bawah ini.
Menunda Rendering
Untuk menunda rendering, klik kotak centang Render di sudut bawah kanan dari status bar. Ketika kotak centang Render tidak diaktifkan, QGIS tidak menggambar ulang kanvas dalam menanggapi setiap kejadian yang telah diuraikan dalam Bagian
Rendering . Contoh ketika Anda mungkin ingin menunda render meliputi:
• Menambah banyak lapisan dan melambangkan mereka sebelum menggambar
• Menambahkan satu atau lebih lapisan besar dan mengatur ketergantungan skala sebelum menggambar
• Menambahkan satu atau lebih lapisan besar dan perbesar ke tampilan spesifik sebelum menggambar
• Kombinasi dari yang ada di atas
Aktifkan kotak centang peta.
Render mengaktifkan rendering dan dan menyebabkan refresh langsung dari kanvas
Pengaturan Lapisan Tambah Opsi
Anda dapat mengatur pilihan untuk selalu memuat lapisan baru tanpa menggambar mereka. Ini berarti lapisan akan ditambahkan ke peta, namun visibilitas kotak centang dalam legenda akan dicentang secara default. Untuk mengatur opsi ini, pilih menu opsi Pengaturan
→
Opsi dan klik tab Rendering . Hapus centang Secara standar lapisan baru ditambahkan ke peta selalu ditampilkan . Setiap lapisan ditambahkan ke peta akan tidak terlihat secara standar.
Menghentikan Rendering
Untuk menghentikan penggambaran peta, tekan tombol
ESC
. Ini akan menghentikan refresh kanvas peta dan menghentikan proses penggambaran peta. Hal ini mungkin membutuhkan waktu selama menekan
ESC dan penggambaran peta terhenti.
Catatan: Saat ini tidak memungkikan untuk menghentikan rendering - ini dinonaktifkan di port qt4 karena masalah antarmuka pengguna (UI) dan konflik (crash).
32 Bab 8. Peralatan Umum
QGIS User Guide, Rilis 2.6
Memperbarui tampilan peta sebelum rendering
Anda dapat mengatur pilihan untuk memperbarui tampilan peta sebagai fitur.
Secara standar, QGIS tidak menampilkan semua fitur untuk lapisan sampai seluruh lapisan telah dirender.Untuk memperbarui tampilan seperti fitur dibaca dari datastore, pilih opsi menu Pengaturan
→
Opsi klik pada menu Rendering . Mengatur jumlah fitur untuk nilai yang sesuai untuk memperbarui tampilan selama rendering. Menetapkan nilai 0 menonaktifkan pembaruan selama menggambar (ini adalah default). Menetapkan nilai terlalu rendah akan menghasilkan kinerja yang buruk pada kanvas peta terus diperbarui selama pembacaan fitur. Nilai yang disarankan untuk memulai adalah 500.
Mempengarui Kualitas Rendering
Untuk mempengaruhi kualitas dari peta Anda memiliki 2 opsi. Pilih opsi menu Pengaturan
→
Opsi klik pada tab
Rendering dan pilih atau tidak kotak centang berikut.
•
•
Membuat garis tampil kurang baik dengan mengorbankan beberapa kinerja menggambar
Memperbaiki masalah isi poligon
Mempercepat rendering
Ada dua pengaturan yang memungkinkan Anda untuk meningkatkan kecepatan rendering. Buka opsi dialog QGIS menggunakan Pengaturan
→
Opsi , ke tab Rendering dan pilih atau tidak kotak centang berikut.
• Enable back buffer . Hal ini memberikan performa grafis yang lebih baik pada kemungkinan kehilangan biaya untuk membatalkan rendering dan secara bertahap menggambar fitur. Jika dicentang, Anda dapat mengatur Jumlah fitur untuk menggambar sebelum memperbarui tampilan , jika pilihan ini tidak aktif.
• Gunakan render caching yang memungkinkan mempercepat gambar ulang
8.4 Mengukur
Mengukur peta dalam proyeksi sistem koordinat (misal UTM) dan data belum terproyeksi. Jika peta dimuat didefinisikan dengan sistem koordinat geografis (lintang/bujur), hasil dari garis atau daerah pengukuran akan salah. Untuk memperbaiki ini, Anda perlu mengatur peta sesuai sistem koordinat (lihat Bagian
berguna, jika Anda ingin mengukur garis atau area di lapisan vektor.
Untuk memilih alat ukur, klik di dan pilih alat yang ingin digunakan.
8.4.1 Mengukur panjang, area dan sudut
Mengukur Garis
: QGIS mampu mengukur jarak nyata antar poin yang diberikan sesuai dengan ellipsoid yang didefinisikan. Untuk mengonfigurasinya, pilih menu opsi Pengaturan
→
Opsi , klik tab Peralatan Peta dan pilih ellipsoid yang tepat. Di sana Anda juga dapat mendefinisikan warna karet gelang (rubberband) dan satuan pengukuran pilihan Anda (meter atau feet) dan satuan sudut (derajat, radian dan gon). Kemudian memungkinkan
Anda untuk mengklik titik pada peta. Setiap panjang-segmen serta total muncul dalam jendela-ukuran. Untuk menghentikan pengukuran klik tombol tetikus sebelah kanan.
Mengukur Area
: Area juga dapat diukur. Pada jendela mengukur muncul ukuran daerah akumulasi. Selain itu, alat ukur akan mengambil (snap) ke lapisan yang sedang dipilih, asalkan lapisan yang memiliki toleransi yang ditetapkan. (Lihat Bagian
Setting the Snapping Tolerance and Search Radius ). Jadi jika Anda ingin mengukur
persis sepanjang fitur garis, atau sekitar fitur poligon, pertama kali atur toleransi snap, kemudian pilih lapisan.
8.4. Mengukur 33
QGIS User Guide, Rilis 2.6
Gambar 8.2: Mengukur Panjang (Gnome)
Sekarang, ketika menggunakan alat ukur, setiap klik tetikus (dalam pengaturan toleransi) akan merekam (snap) ke lapisan itu.
Gambar 8.3: Mengukur Area (Gnome)
Mengukur Sudut
: Anda juga bisa mengukur sudut. Kursor menjadi cross-shaped. Klik untuk menggambar segmen pertama dari sudut yang ingin diukur, kemudian memindahkan kursor untuk menggambar sudut yang diinginkan.
Alat ukur akan ditampilkan dalam dialog pop-up.
Gambar 8.4: Mengukur Sudut (Gnome)
8.4.2 Pilih dan lepas fitur
Toolbar QGIS menyediakan beberapa alat untuk memilih fitur dalam kanvas peta. Untuk memilih satu atau beberapa fitur klik pada dan pilih perangkat Anda:
•
Pilih Fitur Tunggal
•
Pilih Fitur dari Rectangle
•
Pilih Fitur dari Poligon
•
Pilih Fitur dari Freehand
•
Pilih Fitur dari Radius
Untuk melepas semua fitur yang dipilih klik di
Lepas fitur dari semua lapisan
.
Select feature using an expression allow user to select feature using expression dialog. See
chapter for some example.
34 Bab 8. Peralatan Umum
QGIS User Guide, Rilis 2.6
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.
8.5 Fitur Identifikasi
Fitur identifikasi memungkinkan berinteraksi dengan kanvas peta untuk mendapatkan informasi fitur pada sebuah jendela pop-up. Identifikasi fitur menggunakan Tampilan
→
Identifikasi fitur atau tekan Ctrl + Shift + I , atau klik ikon toolbar
Identifikasi fitur
.
Jika Anda klik beberapa fitur, dialog Hasil Identifikasi akan mendaftar semua data atribut dari semua fitur. Item pertama adalah jumlah item dalam daftar hasil diikuti dengan nama lapisan. Kemudian, anak pertama akan menjadi nama sebuah kolom dengan nilainya. Akhirnya semua informasi dari fitur tersebut akan ditampilkan.
Jendela ini dapat disesuaikan untuk menampilkan kolom kustom namun secara default akan menampilkan tiga jenis informasi:
• Aksi-aksi: Aksi-aksi ditambahkan untuk mengidentifikasi fitur windows. Ketika mengklik pada aksi label, aksi akan berjalan. Secara default hanya satu tindakan ditambahkan untuk meihat form fitur untuk mengedit.
• Derived: informasi mereka dihitung atau berasal dari informasi lainnya. Anda bisa menemukan koordinat dengan diklik, koordinat X dan Y, area dalam satuan peta dan parameter peta dalam unit peta untuk poligon, panjang unit peta untuk garis dan id fitur.
• Data atribut: Daftar kolom atribut dari data
Gambar 8.5: Dialog identifikasi fitur (Gnome)
Di bagian bawah dari jendela, Anda memiliki lima ikon:
•
Expand tree
•
Collapse tree
•
Default behaviour
•
Salin atribut
•
Print selected HTML response
Fungsi lain dapat ditemukan dalam menu konteks dari ditentukannya item. Sebagai contoh, dari menu konteks
Anda dapat:
• Lihat form fitur
• Perbesar ke fitur
8.5. Fitur Identifikasi 35
QGIS User Guide, Rilis 2.6
• Salin fitur: salin semua fitur geometri dan atribut
• Toggle feature selection: adds identified feature to selection
• Salin nilai atribut: hanya menyalin nilai dari atribut yang Anda klik
• Salin atribut fitur: hanya menyalin atribut
• Bersihkan hasilnya: Hapus hasil di jendela
• Bersihkan highlight: Hapus fitur highlight pada peta
• Highlight semua
• Highlight lapisan
• Aktifkan lapisan: Pilih lapisan yang akan diaktifkan
• Properti lapisa: buka jendel properti lapisan
• Perluas (expand) semua
• Runtuh (collapse) semua
8.6 Dekorasi
Dekorasi dari QGIS termask Grid, Label Hak Cipta, Panah Utara, dan Bar Skala. Mereka digunakan untuk
‘dekorasi’ peta dengan menambahkan elemen peta.
8.6.1 Kisi (Grid)
Grid memungkinkan untuk menambahkan koordinat kisi (grid) dan koordinat anotasi untuk kanvas peta.
36
Gambar 8.6: Dialog Kisi (Grid)
1. Pilih dari menu Tampilan
→
Decorasi
→
Kisi . Mulai dialog (lihat
2. Aktifkan kotak centang dimuat dalam kanvas peta.
Aktifkan Kisi dan menetapkan definisi kisi (grid) sesuai dengan lapisan yang
3. Aktifkan kotak centang Gambar anotasi dan menetapkan definisi anotasi sesuai dengan lapisan yang dimuat dalam kanvas peta.
4. Klik [Terapkan] untuk memverifikasi bahwa itu tampak seperti yang diharapkan.
Bab 8. Peralatan Umum
5. Klik [OK] untuk menutup dialog.
8.6.2 Label Hak Cipta
Label Hak Cipta menambahkan label hak cipta menggunakan teks untuk peta.
QGIS User Guide, Rilis 2.6
Gambar 8.7: Dialog Hak Cipta
1. Pilih dari menu
Tampilan
→
Dekorasi
→
Label hak Cipta
. (lihat
2. Masukkan teks yang Anda ingin tempatkan di peta. Anda bisa menggunakan HTML seperti dalam contoh
3. Pilih penempatan label dari kotak kombo Penempatan .
4. Pastikan kotak centang telah ditandai/aktifkan Aktifkan Label Hak Cipta
5. Klik [OK] .
Dalam contoh di atas, yang merupakan default, QGIS menempatkan simbol hak cipta diikuti dengan tanggal di bagian bawah sudut kanan dari kanvas peta.
8.6.3 Panah Utara
Panah Utara menempatkan panah utara sederhana di kanvas peta. Saat ini hanya ada satu gaya yang tersedia.
Anda dapat mengatur sudut panah atau membiarkan QGIS mengatur arah secara otomatis. Jika Anda memilih untuk membiarkan QGIS menentukan arah, itu membuat QGIS menebak yang terbaik bagaimana panah harus berorientasi. Untuk penempatan panah, Anda memiliki empat pilihan, sesuai dengan empat penjuru kanvas peta.
Gambar 8.8: Dialog Panah Utara
8.6. Dekorasi 37
QGIS User Guide, Rilis 2.6
8.6.4 Bar Skala
Skala Bar menambahkan bar skala sederhana untuk kanvas peta. Anda bisa mengontrol gaya dan penempatan, serta pelabelan bar.
Gambar 8.9: Dialog Bar Skala
QGIS hanya mendukung menampilkan skala dalam satuan yang sama dengan kerangka peta Anda. Jadi jika satuan lapisan Anda dalam meter, Anda tidak dapat membuat skala bar dalam kaki (feet). Demikian juga jika
Anda menggunakan derajat desimal, Anda tidak dapat membuat skala bar untuk menampilkan jarak dalam meter.
Menambahkan bar skala:
1. Pilih dari menu Tampilan
→
Dekorasi
→
Skala Bar (lihat
2. Pilih penempatan label dari kotak kombo Penempatan
3. Pilih gaya dari kotak kombo Gaya skala bar
4. Pilih warna bar
Warna bar
5. Atur ukuran bar dan labelnya
Ukuran bar
.
atau gunakan hitam warna default.
6. Pastikan kotak centang sudah aktif Aktifkan skala bar
7. Opsional, centang Automatically snap to round number on resize .
8. Klik
[OK]
.
Tip: Pengaturan Dekorasi
Saat Anda menyimpan sebuah proyek
.qgs
, setiap perubahan yang Anda buat pada Kisi (Grid), Panah Utara,
Skala Bar dan Hak Cipta akan disimpan dalam proyek dan dikembalikan pada saat Anda memuat proyek.
8.7 Peralatan Anotasi
Peralatan
Anotasi Teks dalam toolbar atribut memberikan kemungkinan untuk menempatkan teks diformat dalam balon pada kanvas Peta QGIS. Gunakan alat Anotasi Teks dan klik kedalam kanvas peta.
Dobel klik pada item membuka dialog dengan berbagai pilihan. Ada editor teks untuk memasukkan teks yang diformat dan pengaturan item lain. Misalnya ada pilihan memiliki item ditempatkan pada posisi peta (ditampilkan dengan simbol penanda) atau memiliki item pada posisi layar (tidak berhubungan dengan peta). Item ini bisa dipindahkan dengan posisi peta (geser penanda peta) atau hanya dengan memindahkan balon. Ikon adalah bagian dari tema GIS, dan digunakan secara default dalam tema-tema lain juga.
38 Bab 8. Peralatan Umum
QGIS User Guide, Rilis 2.6
Gambar 8.10: Dialog teks anotasi
Alat
Pindah Anotasi memungkinkan memindah anotasi pada kanvas peta.
8.7.1 Anotasi HTML
Alat
Anotasi Html dalam toolbar atribut memberikan kemungkinan untuk menempatkan isi berkas HTML dalam balon pada kanvas Peta QGIS. Gunakan alat Anotasi Html dan klik kedalam kanvas peta dan menambahkan path ke berkas html ke dalam dialog.
8.7.2 Anotasi SVG
Alat
Anotasi SVG dalam toolbar atribut memberikan kemungkinan untuk menempatkan simbol SVG dalam balon pada kanvas Peta QGIS. Gunakan alat Anotasi SVG dan klik kedalam kanvas peta dan menambahkan path ke berkas SVG ke dalam dialog.
8.7.3 Form anotasi
Selain itu Anda juga dapat membuat form anotasi Anda sendiri.
Alat
Form Anotasi ini berguna untuk menampilkan atribut dari lapisan vektor dalam form desainer qt disesuaikan (lihat
Hal ini mirip dengan form desainer alat Identifikasi fitur , tetapi ditampilkan dalam item anotasi. Lihat juga video https://www.youtube.com/watch?v=0pDBuSbQ02o dari Tim Sutton untuk informasi lebih lanjut.
Catatan: Jika Anda menekan
Ctrl+T sementara alat
Anotasi aktif (anotasi bergerak, anotasi teks, form anotasi), visibilitas item yang terbalik.
8.8 Bookmark Spasial
Bookmark spasial memungkinkan Anda untuk “bookmark” lokasi geografis dan kembali ke spasial ini suatu saat nanti.
8.8. Bookmark Spasial 39
QGIS User Guide, Rilis 2.6
Gambar 8.11: Disesuaikan form anotasi bentuk desainer qt
8.8.1 Membuat Bookmark
Membuat Bookmark
1. Perbesar atau geser ke interes area.
2. Pilih menu opsi Tampilan
→
Bookmark Baru atau tekan
Ctrl-B
.
3. Masukkan nama deskripsi dari bookmark (batas 255 karakter).
4. Tekan
Enter untuk menambahkan bookmark atau [Delete] untuk menghapus bookmark.
Catatan Anda bisa memiliki bookmark banyak dengan satu nama.
8.8.2 Bekerja dengan Bookmark
Menggunakan atau mengelola bookmark, pilih menu opsi Tampilan
→
Tampilkan Bookmark . Dialog Geospatial
Bookmark memungkinkan Anda untuk memperbesar atau menghapus bookmark. Anda tidak dapat mengedit nama bookmark atau koordinat.
8.8.3 Perbesar ke Bookmark
Dari dialog
Geospasial Bookmark
, pilih bookmark yang diinginkan dengan mengkliknya, kemudian klik [Perbesar] . Anda juga bisa memperbesar ke bookmark dengan dobel-klik padanya.
8.8.4 Menghapus Bookmark
Menghapus bookmark dari dialog Geospasial Bookmark , klik padanya dan kemudian klik [Hapus] . Konfirmasi
Anda pilih dengan klik
[Ya] atau batal menghapus dengan klik
[Tidak]
.
40 Bab 8. Peralatan Umum
QGIS User Guide, Rilis 2.6
8.9 Proyek-proyek Nesting
Jika Anda ingin menanamkan (embed) isi dari berkas proyek lain kedalam proyek Anda, Anda bisa memilih
Lapisan
→
Tanam Lapisan dan Grup .
8.9.1 Menanam (Embedding) lapisan
Dialog berikut memungkinkan Anda menanamkan lapisan dari proyek-proyek lain. Berikut ini adalah contoh kecil:
1. Tekan untuk mencari proyek lain dari dataset Alaska.
2. Pilih berkas proyek grassland
. Anda bisa melihat konten dari proyek (lihat
3. Tekan
Ctrl dan klik pada lapisan grassland dan regions
. Tekan [OK] . Lapisan akan ditanam dalam legenda peta dan tampilan peta sekarang.
Gambar 8.12: Pilih lapisan-lapisan dan grup-grup untuk ditanam (embed)
Sementara lapisan tertanam dapat diedit, Anda tidak dapat mengubah properti mereka seperti gaya dan pelabelan.
8.9.2 Menghapus lapisan-lapisan ditanam (embdded)
.
Klik-kanan pada lapisan yang ditanam (embedded) dan pilih
Hapus
.
8.9. Proyek-proyek Nesting 41
QGIS User Guide, Rilis 2.6
42 Bab 8. Peralatan Umum
BAB
9
Konfigurasi QGIS
QGIS dapat dikonfigurasi melalui menu Pengaturan . Pilih diantara Panel, Toolbar, Properti Proyek, Opsi dan
Penyesuaian.
Catatan: 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 Panel dan Toolbar
Dalam menu Panel
→
Anda bisa mengatifkan dan menonaktfikan widget QGIS. Menu Toolbar
→ memberikan kemungkinan mengaktfikan dan menonatifkan ikon grup di toolbar QGIS (lihat
Gambar 9.1: Menu Panel dan Toolbar
Tip: Mengaktifkan Tinjauan QGIS
43
QGIS User Guide, Rilis 2.6
Di QGIS Anda dapat menggunakan panel gambaran yang menyediakan tampilan lapisan tingkat penuh yang ditambahkan ke dalamnya. Hal ini dapat dipilih di bawah menu Tampilan
→
Panel . Dalam pandangan persegi panjang yang menunjukkan tingkat peta saat ini. Hal ini memungkinkan Anda dengan cepat menentukan area peta yang sedang Anda lihat. Perhatikan bahwa label tidak diberikan ke gambaran peta bahkan jika lapisan dalam gambaran peta telah diatur untuk pelabelan. Jika Anda klik dan tarik persegi panjang merah dalam gambaran yang menunjukkan gambaran Anda saat ini, tampilan utama peta akan memperbarui.
Tip: Tampilkan Pesan Log
Ini memungkinkan untuk melacak pesan QGIS. Anda bisa mengaktifkan
Log Pesan dalam menu
Pengaturan
→
Panel dan ikuti pesan yang muncul dalam tab yang berbeda selama memuat dan operasi.
9.2 Properti Proyek
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
• Di dalam menu Umum judul proyek, seleksi dan warna latar, satuan lapisan, presisi, dan pilihan untuk menyimpan path relatif terhadap lapisan yang dapat ditentukan. Jika transformasi CRS aktif Anda dapat memilih ellipsoid untuk perhitungan jarak. Anda dapat menentukan satuan kanvas (hanya digunakan ketika transformasi CRS dinonaktifkan) dan ketepatan desimal untuk digunakan. Anda juga dapat menentukan daftar skala proyek, yang menimpa skala yang telah ditentukan global.
• Menu CRS memungkinkan Anda untuk memilih Coordinat Reference System untuk proyek ini, dan memungkinkan proyeksi ulang on-the-fly lapisan raster dan lapisan vektor ketika menampilkan lapisan dari CRS yang berbeda.
• Dengan menu ketiga
Identifikasi lapisan
Anda atur (atau nonaktif) lapisan akan merespon alat mengidentifikasi (lihat paragraf “peralatan Peta” dari bagian
untuk mengaktifkan identifikasi atau lapisan multi).
• 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.
• Tab OWS Server memungkinkan untuk menentukan informasi tentang Server WMS dan kapabilitas WFS
QGIS, Pada Tingkat dan Pembatasan CRS.
• Menu Macros digunakan untuk mengedit Python macros untuk proyek. Saat ini, hanya tiga macro yang tersedia: openProject() , saveProject() dan closeProject() .
• Menu Relasi digunakan untuk menentukan relasi 1:n. Relasi ditentukan dalam dialog properti proyek. Setelah ada relasi lapisan, elemen antarmuka pengguna baru form tampilan (misalnya ketika mengidentifikasi fitur dan membuka form) akan daftar entitas terkait. Ini menyediakan cara ampuh mengekspresikan misalnya sejarah inspeksi pada panjang pipa atau segmen jalan. Anda bisa menemukan lebih jauh tentang relasi
1:n di Bagian
Creating one to many relations .
9.3 Opsi
Beberapa pilihan dasar untuk QGIS dapat dipilih menggunakan dialog Opsi . Pilih menu opsi Pengaturan
→
Opsi . Tab di mana Anda dapat menyesuaikan pilihan Anda dijelaskan di bawah ini.
44 Bab 9. Konfigurasi QGIS
QGIS User Guide, Rilis 2.6
Gambar 9.2: Pengaturan Macro di QGIS
9.3.1 Menu Umum
Aplikasi
• Pilih
Gaya (QGIS diperlukan restart) tique’ dan ‘Cleanlooks’ ( ).
• Definisikan Ikon tema dan pilih diantara ‘Oxygen’,’Windows’,’Motif’,’CDE’, ‘Plas-
. Sekarang hanya ‘default’.
• Definisikan Ukuran Ikon .
• Definisikan Font . Pilih antara QT default dan font user-defined.
• Ubah Timeout for timed messages or dialogs .
•
•
Sembunyikan layar splash saat startup
Tampilkan Petunjuk saat startup
•
•
Judul tebal kotak grup
QGIS-styled kotak grup
• Gunakan dialog pemilih warna live-updating
Berkas proyek
• Buka proyek pada peluncuran
‘khusus’ menggunakan
(memilih antara ‘Baru’. ‘Terbaru’ dan ‘Khusus’). Ketika memilih untuk menentukan proyek.
•
Buat proyek baru dari proyek default
. Anda memiliki kemungkinan untuk menekan
Atur proyek sekarang sebagai default atau pada Reset default . Anda dapat menelusuri melalui berkas-berkas dan menentukan direktori dimana Anda menemukan pengguna-ditetapkan proyek template Anda. Akan ada sebuah entri di
Project
→
Baru dari Template jika Anda pertama kali mengaktifkan proyek default dan kemudian simpan proyek dalam folder proyek template.
Buat proyek baru dari
•
Prompt untuk menyimpan proyek dan sumber data perubahan bila diperlukan
9.3. Opsi 45
QGIS User Guide, Rilis 2.6
• Peringatkan ketika membuka berkas proyek QGIS yang disimpan dengan versi lama
• Aktifkan macros . Opsi ini digunakan untuk menangani macro yang ditulis untuk melakukan tindakan pada peristiwa proyek. Anda bisa memilih diantara ‘Tidak pernah’, ‘Bertanya’, ‘Hanya untuk sesi ini’ dan
‘Selalu (tidak direkomendasikan)’.
9.3.2 Menu Sistem
Lingkungan
Sistem lingkungan variabel saat ini dapat dilihat dan banyak dikonfigurasi dalam menu Lingkungan (lihat
mewarisi lingkungan shell pengguna. Ini juga berguna untuk pengaturan / melihat lingkungan variabel untuk mengatur alat eksternal yang dikendalikan oleh pengolahan toolbox (seperti SAGA, GRASS), dan untuk menyalakan keluaran debugging untuk bagian tertentu dari kode sumber.
• Gunakan penyesuaian variabel (dibutuhkan restart - termasuk pemisah) . Anda bisa [Tambah] dan
[Hapus] variabel. Variabel lingkungan yang sudah ditetapkan akan ditampilkan dalam:guilabel: Variabel lingkungan sekarang , dan hal itu memungkinkan untuk menyaring mereka dengan mengaktifkan
Tampilkan hanya variabel spesifik-QGIS .
Gambar 9.3: Sistem lingkungan variabel dalam QGIS
Plugin path
[Tambah] atau [Hapus] Path(s) untuk mencari tambahan C++ librari Plugin
9.3.3 Menu sumber data
Atribut dan tabel fitur
46 Bab 9. Konfigurasi QGIS
QGIS User Guide, Rilis 2.6
• Buka tabel atribut di dock window (dibutuhkan restart QGIS)
• Salin geometri di representasi WKT dari tabel atribut .
Ketika menggunakan
Salin baris yang dipilih ke papan klip dari menu Tabel atribut kemudian ini memiliki hasil yang juga koordinat titik atau simpul disalin ke papan klip.
• Perilaku tabel atribut . Ada tiga kemungkinan: ‘Tampilkan semua fitur’, ‘Tampilkan fitur dipilih’ dan
‘Tampilkan fitur terlihat pada peta’
• Tabel atribut baris cache . Baris cache ini memungkinkan untuk menyimpan baris x atribut terakhir dimuat sehingga proses tabel atribut akan lebih cepat. Cache akan dihapus ketika menutup tabel atribut.
• Representasi untuk nilai NULL Here you can define a value for data fields containing a NULL value. Di sini Anda dapat menentukan nilai untuk bidang data yang berisi nilai NULL.
Menangani sumber data
• Pindai item yang valid di dock Browser isi berkas’.
. Anda dapat memilih antara ‘Periksa ekstensi’ dan ‘Periksa
• Pindai isi dari berkas yang dikompresi (.zip) di browser dock ful’ memungkinkan.
. ‘Tidak’, ‘Pindai dasar’ and ‘Pindai
• Konfirmasi sublapisan raster saat membuka . Beberapa raster mendukung sublapisan – mereka disebut subdataset di GDAL. Contohnya adalah berkas netCDF - jika ada banyak variabel netCDF, GDAL melihat setiap variabel sebagai sub dataset. Pilihan ini untuk mengontrol bagaimana menangani sub-lapisan ketika sebuah berkas dengan sub-lapisan dibuka. Anda memiliki pilihan berikut:
–
‘Selalu’: Selalu bertanya (jika ada sub-lapisan yang ada)
– ‘Jika diperlukan’: Menanyakan apakah lapisan tidak memiliki band, namun memiliki sub-lapisan
– ‘Tidak Pernah’: Tidak pernah meminta, tidak akan memuat apa-apa
– ‘Muat semua’: Tidak pernah meminta, tetapi memuat semua sub-lapisan
• Abaikan deklarasi encoding shapefile . Jika shapefile punya pengkodean informasi ini akan diabaikan oleh QGIS.
•
•
Tambahkan lapisan PostGIS dengan klik ganda dan pilih dalam mode diperpanjang
Tambahkan lapisan Oracle with dobel klik dan pilih dalam mode diperpanjang
9.3.4 Menu Rendering
Tindakan rendering
• Secara default lapisan baru yang ditambahkan ke peta harus ditampilkan
•
•
Gunakan render caching yang memungkinkan mempercepat gambar ulang
Render layers in parallel using many CPU cores
• Max cores to use
• Map update interval (default to 250 ms)
• Aktifkan fitur simplication secara default untuk lapisan baru yang ditambahkan
• Simplification threshold
• Sederhanakan di sisi penyedia jika mungkin
•
Maximum scale at which the layer should be simplified
9.3. Opsi 47
QGIS User Guide, Rilis 2.6
Kualitas rendering
• Membuat garis tampil kurang bagus dengan mengorbankan beberapa kinerja menggambar
Raster-raster
• Dengan RGB band seleksi Anda bisa menetapkan nomor dari band Merah, Hijau dan Biru.
Contrast enhancement
• Band abu-abu tunggal . Sebuah band abu-abu tunggal dapat memiliki ‘Tidak ada peregangan’,
‘Lakukan peregangan untuk MinMax’, ‘Peregangan dan Klip ke MinMax’ dan juga ‘Clip ke MinMax’
• band multi warna (byte/band) . Opsinya antara lain ‘Tidak ada peregangan’, ‘Lakukan peregangan untuk MinMax’, ‘Peregangan dan Klip ke MinMax’ dan juga ‘Clip ke MinMax’.
• band multi warna (>byte/band) . Opsinya antara lain ‘Tidak ada peregangan’, ‘Lakukan peregangan untuk MinMax’, ‘Peregangan dan Klip ke MinMax’ dan juga ‘Clip ke MinMax’
• Batas (minimum/maksimum) .
Opsinya adalah ‘Kumulatif jumlah potong pixel’, ‘Minimum/Maksimum’, ‘Berarti +/- standar deviasi’.
• Kumulatif batas jumlah potong pixel
• Standar deviasi multiplier
Debugging
•
Refresh kanvas peta
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 Menu Kanvas dan Legenda
Standar penampilan peta (diganti oleh proyek properti)
• Tetapkan Seleksi warna dan Warna latar .
Legenda lapisan
•
Dobel klik pada legenda klik.
• Mengikuti Gaya item legenda :
. Anda dapat ‘Buka properti lapisan’ atau ‘Buka atribut tabel’ dengan dobel
–
–
Nama lapisan kapital
Nama lapisan tebal
–
–
–
–
Nama grup tebal
Tampilkan klasifikasi nama atribut
Buat ikon raster (mungkin lambat)
Tambah lapisan baru ke grup sekarang atau yang dipilih
48 Bab 9. Konfigurasi QGIS
QGIS User Guide, Rilis 2.6
9.3.7 Menu perangkat Peta
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.
• 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.
Alat pengukuran
• Tentukan Warna Rubberband untuk peralatan pengukuran
• Tentukan
Tempat desimal
•
Perlu satuan dasar
• Satuan pengukuran yang dipilih (‘Meter’, ‘Kaki’, ‘Mil laut’ atau ‘derajat’)‘
• Satuan sudut yang dipilih (‘Derajat’, ‘Radian’ atau ‘Gon’)
Menggeser dan memperbesar
• Tentukan Aksi roda tetikus ada’)
(‘Perbesar’, ‘Perbesar dan pusat’, ‘Perbesar pada kursor tetikus’, ‘Tidak
• Tentukan Faktor pembesaran untuk roda tetikus
Skala yang ditentukan
Di sini Anda menemukan daftar skala yang telah ditentukan. Dengan tombol [+] dan [-] Anda dapat menambahkan atau menghapus skala individu Anda.
9.3.8 Menu Penyusun
Standar Komposisi
Anda bisa menentukan font Default disini.
Penampilan Kotak
(‘Solid’, ‘Dots’, ‘Crosses’) • Tentukan the Gaya Kotak
• Tentukan Warna...
Standar kotak
• Tentukan Spacing
• Tentukan Ofset kotak
• Tentukan Toleransi Snap
Standar panduan
• Tentukan Toleransi Snap untuk x dan y
9.3. Opsi 49
QGIS User Guide, Rilis 2.6
9.3.9 Menu Digitalisasi
Membuat fitur
•
Menekan atribut jendela pop-up setelah setiap fitur dibuat
•
Gunakan kembali nilai atribut terakhir yang dimasukkan
• Validasi geometris . Mengedit garis/poligon kompleks dengan banyak node menyebabkan render sangat lambat. Hal ini karena prosedur standar validasi di QGIS dapat menghabiskan banyak waktu. Untuk mempercepat rendering itu dengan memilih validasi geometri GEOS (mulai dari GEOS 3.3) atau untuk mematikannya. Validasi geometri GEOS jauh lebih cepat, tetapi masalahnya adalah bahwa hanya geometri pertama yang akan dilaporkan.
Rubberband
• Tentukan Rubberband Lebar garis dan Warna garis
Snapping
• Buka opsi mengambil di dock window (dibutuhkan restart QGIS)
• Tentukan Mode standar snap (‘Simpul’, ‘Segmen’, ‘Simpul dan Segmen’, ‘Mati’)
• Tentukan Default toleransi snapping dalam satuan peta atau pixel
• Tentukan Cari radius untuk suntingan simpul dalam satuan peta atau pixel
Penanda simpul
• Tampilkan penanda hanya untk fitur yang dipilih
• Tentukan simpul Gaya Penanda
• Tentukan simpul Ukuran Penanda
Alat ofset kurva
(‘Palang’ (standar), ‘Lingkaran semi transparan’ atau ‘Tidak ada’)
3 pilihan berikutnya mengacu pada alat
Kurva Ofset dalam
Advanced digitizing . Melalui berbagai pengaturan,
ini memungkinkan untuk mempengaruhi bentuk garis ofset. Opsi-opsi ini mungkin dimulai dari GEOS 3.3.
•
Gaya Join
• Segmen Quadrant
• Batas Miter
9.3.10 Menu GDAL
GDAL adalah data pertukaran librari untuk berkas raster. Dalam tab ini Anda dapat Edit membuat opsi dan Edit
Opsi Pyramid dari format raster. Menentukan driver GDAL yang akan digunakan untuk format raster seperti dalam beberapa kasus lebih dari satu driver GDAL tersedia.
9.3.11 Menu CRS
CRS standar untuk proyek baru
•
Jangan diaktifkan proyeksi ulang ‘on the fly’
• Aktif otomatis proyeksi ulang ‘on the fly’ jika lapisan memiliki CRS berbeda
• Mengaktifkan proyeksi ulang ‘on the fly’ secara default
• Pilih sebuah CRS dan Selalui mulai proyek baru dengan CRS ini
50 Bab 9. Konfigurasi QGIS
QGIS User Guide, Rilis 2.6
CRS untuk lapisan baru
Daerah ini memungkinkan untuk menentukan tindakan ketika sebuah lapisan baru dibuat, atau ketika lapisan tanpa
CRS dimuat.
• Konfirmasi CRS
• Gunakan CRS proyek
• Gunakan standar CRS ditampilkan dibawah ini
Transformasi datum standar
• Mintalah transformasi datum bila tidak ada standar yang ditentukan
• Jika Anda telah bekerja dengan transformasi CRS ‘on-the-fly’ Anda bisa melihat hasil dari transformasi dalam jendela di bawah. Anda bisa menemukan informasi tentang ‘Sumber CRS’ dan ‘Destinasi CRS’ maupun ‘Sumber datum transform’ dan ‘Destinasi datum transform’.
9.3.12 Menu Lokal
• Timpah sistem lokal dan Lokal gunakan sebagai pengganti
• Informasi tentang sistem lokal aktif
9.3.13 Menu Jaringan
Umum
• Tentukan
WMS cari alamat
, default http://geopole.org/wms/search?search=\%1\&type=rss
• Tentukan Timeout untuk permintaan jaringan (ms) - default 60000
• Tentukan Standar periode ekspirasi untuk WMSC/WMTS (jam) - default 24
• Tentukan Mencoba kembali Maksimum jika terjadi kesalahan permintaan genteng
• Tentukan User-Agent
Pengaturan cache
Tentukan Direktori dan Ukuran untuk cache.
• Gunakan proxy untuk akses web dan tentukan ‘Host’, ‘Port’, ‘Pengguna’, and ‘Kata Sandi’.
• Atur Tipe Proxy sesuai dengan kebutuhan Anda.
– Proxy Standar : Proxy ditentukan berdasarkan aplikasi pengaturan menggunakan proxy
–
Socks5Proxy : Proxy generik untuk setiap jenis koneksi. Mendukung TCP, UDP, mengikat ke port
(koneksi masuk) dan otentikasi.
–
HttpProxy
: Menggunakan perintah “CONNECT”, mendukung hanya koneksi TCP; mendukung otentikasi.
– HttpCachingProxy : Menggunakan perintah normal HTTP, itu hanya berguna dalam konteks permintaan HTTP.
– FtpCachingProxy : Menggunakan proxy FTP, itu hanya berguna dalam konteks permintaan FTP.
Tidak termasuk beberapa URL dapat ditambahkan ke kotak teks di bawah pengaturan-proxy (lihat
Jika Anda membutuhkan informasi lebih rinci tentang pengaturan-proxy yang berbeda, silakan lihat panduan QTlibrari-dokumentasi di http://doc.trolltech.com/4.5/qnetworkproxy.html#ProxyType-enum .
Tip: Menggunakan Proxi
9.3. Opsi 51
QGIS User Guide, Rilis 2.6
52
Gambar 9.4: Pengaturan-proxy di QGIS
Bab 9. Konfigurasi QGIS
QGIS User Guide, Rilis 2.6
Menggunakan proxi kadang-kadang bisa rumit. Hal ini berguna ‘coba dan eror’ jenis proxi di atas, untuk memeriksa apakah mereka berhasil dalam kasus Anda.
Anda dapat mengubah pilihan sesuai dengan kebutuhan Anda. Beberapa perubahan mungkin memerlukan restart
QGIS sebelum berjalan efektif.
• Settings are saved in a text file:
$HOME/.config/QGIS/QGIS2.conf
• Anda dapat menemukan pengaturan Anda di:
$HOME/Library/Preferences/org.qgis.qgis.plist
• pengaturan terkirim ke registri:
HKEY\CURRENT_USER\Software\QGIS\qgis
9.4 Penyesuaian (Customization)
Alat penyesuaian memungkinkan Anda mengaktifkan (dan nonaktif) hampir setiap elemen dalam antar muka
QGIS. Hal ini bisa sangat berguna jika Anda memiliki banyak plugin yang dipasang bahwa Anda tidak pernah menggunakan dan mengisi layar Anda.
Gambar 9.5: Dialog penyesuaian
Penyesuaian QGIS dibagi menjadi lima kelompok. Dalam Menu Anda dapat menyembunyikan entri dalam
Menu bar. Dalam Panel Anda dapat menemukan Panel jendela. Jendela Panel adalah aplikasi yang dapat dimulai dan digunakan sebagai mengambang, jendela tingkat-atas atau tertanam ke jendela utama QGIS sebagai widget. (lihat juga tifkan. Dalam
Toolbars
Anda dapat mengaktifkan (non aktif) ikon toolbar QGIS dan mengaktifkan (non aktif) dialog serta tombol mereka.
Status Bar seperti informasi koordinat dapat dinonak-
Widgets Anda dapat
.
Dengan
Beralih ke penangkapan widget dalam aplikasi utama
Anda dapat klik elemen dalam QGIS yang Anda ingin menyembunyikan dan menemukan entri yang sesuai dalam Penyesuaian (lihat
figure_customization ). Anda juga
dapat menyimpan berbagai setup yang berbeda untuk kasus penggunaan yang berbeda juga. Sebelum perubahan diterapkan, Anda harus me-restart QGIS.
9.4. Penyesuaian (Customization) 53
QGIS User Guide, Rilis 2.6
54 Bab 9. Konfigurasi QGIS
BAB
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
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 well-known 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
are:
•
•
Prompt for CRS
Use project CRS
55
QGIS User Guide, Rilis 2.6
56
Gambar 10.1: CRS tab in the QGIS Options Dialog
Bab 10. Working with Projections
QGIS User Guide, Rilis 2.6
• 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
for rasters and
for vectors). If your layer already has a CRS defined, it will be displayed as shown in
Tip: CRS in the Map Legend
Right-clicking on a layer in the Map Legend (section
Legenda Peta ) provides two CRS shortcuts.
Set layer CRS takes you directly to the Coordinate Reference System Selector dialog (see
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
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.
Tip: 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.
10.3. Define On The Fly (OTF) Reprojection 57
QGIS User Guide, Rilis 2.6
Gambar 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.
58 Bab 10. Working with Projections
QGIS User Guide, Rilis 2.6
Gambar 10.3: Custom CRS Dialog
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 .
10.5. Default datum transformations 59
QGIS User Guide, Rilis 2.6
60 Bab 10. Working with Projections
BAB
11
QGIS Peramban
Penjelajah QGIS adalah panel di QGIS yang memungkinkan Anda dengan mudah menavigasi dalam basisdata
Anda. Anda memiliki akses ke berkas-berkas vektor umum (seperti berkas ESRI shapefile atau MapInfo), basisdata (seperti PostGIS, Oracle, Spatialite atau MSSQL Spatial) dan koneksi WMS/WFS. Anda juga bisa melihat data GRASS Anda (untuk mendapatkan data ke QGIS, lihat
Gambar 11.1: Penjelajah QGIS merupakan aplikasi mandiri
Menggunakan penjelajah QGIS untuk menampilkan data Anda. Fungsi geser dan taruh membuatnya mudah untuk menempatkan data Anda ke tampilan peta dan legenda peta.
1. Mengaktifkan penjelajah QGIS. Klik-kanan pada toolbar dan centang Peramban atau pilih dari Pengaturan
→
Panel .
2. Geser panel kedalam jendela legenda dan riliskan.
3. Klik pada tab Peramban
4. Jelajahi dalam basisdata Anda dan pilih folder shapefile dari direktori qgis_sample_data
.
5. Tekan tombol
Shift dan pilih berkas airports.shp
dan alaska.shp
.
6. Tekan tombol kiri tetikus kemudian geser dan tempatkan berkas ke dalam kanvas peta.
61
QGIS User Guide, Rilis 2.6
7. Klik-kanan pada lapisan dan pilih Atur CRS proyek dari lapisan . Untuk informasi lebih lanjut lihat
8. Klik pada
Perbesar Full agar lapisan-lapisan terlihat.
Ada penjelajah kedua yang tersedia di Pengaturan
→
Panel . Hal ini berguna bila Anda perlu untuk memindahkan berkas atau lapisan antar lokasi.
1. Mengaktifkan penjelajah QGIS kedua: Klik-kanan pada toolbar dan centang Penjelajah (2) , atau pilih dari Pengaturan
→
Panel .
2. Geser panel kedalam jendela legenda
3. Arahkan ke tab Peramban (2) dan temukan shapefile di dalam sistem berkas Anda.
4. Pilih sebuah berkas dengan tombol kiri tetikus.
Sekarang Anda bisa menggunakan ikon
Tambah Lapisan Terpilih untuk menambahkannya kedalam proyek sekarang.
QGIS otomatis terlihat untuk Coordinate Reference System (CRS) dan perbesar ke batas lapisan jika Anda bekerja di sebuah proyek kosong QGIS. Jika sudah ada berkas dalam proyek Anda, berkas hanya akan ditambahkan dan dalam kasus itu memiliki tingkat yang sama dan CRS akan divisualisasikan. Jika berkas ini telah mendapat CRS lain dan lapisan Anda terlebih dahulu klik kanan pada lapisan dan pilih Atur CRS Proyek dari Lapisan . Kemudian pilih Perbesar ke Batas Lapisan .
Fungsi
Saring Berkas bekerja pada level direktori. Jelajahi folder dimana Anda ingin menyaring berkas-berkas dan memberikan kata pencarian atau wildcard. Penjelajah hanya menampilkan nama berkas yang sesuai – data lain tidak akan ditampilkan.
Ini juga mungkin untuk menjalankan penjelajah QGIS sebagai aplikasi mandiri.
Mulai Penjelajah QGIS
• ketik di dalam “qbrowser” di perintah prompt.
• Mulai penjelajah QGIS menggunakan menu Start atau desktop shortcut.
.
• Peramban QGIS juga tersedia di fodler Aplikasi Anda.
Dalam
Tab Param menyediakan detail dari koneksi dataset seperti PostGIS atau MSSQL Spatial. Tab Metadata berisi informasi umum tentang berkas (lihat
Preview Anda bisa melihat-lihat di berkas
Anda tanpa mengimpor mereka ke proyek QGIS Anda. Ini juga mungkin untuk melihat atribut berkas Anda dalam tab Atribut
62 Bab 11. QGIS Peramban
BAB
12
Pekerjaan dengan Data Vektor
.
12.1 Supported Data Formats
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
Literatur dan Referensi Web ).
The complete list is available at http://www.gdal.org/ogr/ogr_formats.html
.
Catatan: 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
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 Shapefiles
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
.
63
QGIS User Guide, Rilis 2.6
Loading a Shapefile
To load a shapefile, start QGIS and click on the
Add Vector Layer
This will bring up a new window (see
toolbar button, or simply press
Ctrl+Shift+V
.
Gambar 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
The selection box
Filter allows you to preselect some OGR-supported file formats.
You can also select the encoding for the shapefile if desired.
Gambar 12.2: Open an OGR Supported Vector Layer Dialog
Selecting a shapefile from the list and clicking [Open] loads it into QGIS.
shows QGIS after loading the alaska.shp
file.
Tip: Layer Colors
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
64 Bab 12. Pekerjaan dengan Data Vektor
QGIS User Guide, Rilis 2.6
Gambar 12.3: QGIS with Shapefile of Alaska loaded legend and choosing Properties from the context menu. See section
for more information on setting symbology of vector layers.
Tip: 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
12.1. Supported Data Formats 65
QGIS User Guide, Rilis 2.6
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
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.
66 Bab 12. Pekerjaan dengan Data Vektor
QGIS User Guide, Rilis 2.6
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
Gambar 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 checkbox.
DMS coordinates
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
Discard empty fields
Trim 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.
12.1. Supported Data Formats 67
QGIS User Guide, Rilis 2.6
•
•
Use subset index .
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
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.
68 Bab 12. Pekerjaan dengan Data Vektor
QGIS User Guide, Rilis 2.6
• 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:
–
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
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.
Tip: 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.
12.1. Supported Data Formats 69
QGIS User Guide, Rilis 2.6
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
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
for more information on spatial reference systems and projections.
Tip: 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.
70 Bab 12. Pekerjaan dengan Data Vektor
QGIS User Guide, Rilis 2.6
To import a shapefile into PostGIS, do the following: 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
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
Literatur dan Referensi Web ) 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
12.1. Supported Data Formats 71
QGIS User Guide, Rilis 2.6
we open such a map in QGIS, we will see two far, distinct locations, that should appear near each other. In
the right of the New Zealand main islands.
Gambar 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.
Gambar 12.6: Crossing 180° longitude applying the ST_Shift_Longitude function
Usage
• 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.
72 Bab 12. Pekerjaan dengan Data Vektor
QGIS User Guide, Rilis 2.6
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 .
Tip: 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.
12.1. Supported Data Formats 73
QGIS User Guide, Rilis 2.6
• 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.
• 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.
Tip: 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
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.
Tip: Oracle Spatial Layers
Normally, an Oracle Spatial layer is defined by an entry in the
USER_SDO_METADATA table.
74 Bab 12. Pekerjaan dengan Data Vektor
QGIS User Guide, Rilis 2.6
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.
Tip: 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.
12.2. The Symbol Library 75
QGIS User Guide, Rilis 2.6
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 ...
76 Bab 12. Pekerjaan dengan Data Vektor
QGIS User Guide, Rilis 2.6
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
for an example of custom color ramp and
for the cpt-city dialog.
.
The cpt-city option opens a new dialog with hundreds of themes included ‘out of the box’.
12.2. The Symbol Library 77
QGIS User Guide, Rilis 2.6
Gambar 12.7: Example of custom gradient color ramp with multiple stops
78
Gambar 12.8: cpt-city dialog with hundreds of color ramps
Bab 12. Pekerjaan dengan Data Vektor
QGIS User Guide, Rilis 2.6
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.
Gambar 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.
12.3. The Vector Properties Dialog 79
QGIS User Guide, Rilis 2.6
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.
Gambar 12.10: Save Style in database Dialog
Tip: 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
• 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.
80 Bab 12. Pekerjaan dengan Data Vektor
QGIS User Guide, Rilis 2.6
Gambar 12.11: Single symbol line properties
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
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
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;
12.3. The Vector Properties Dialog 81
QGIS User Guide, Rilis 2.6
Gambar 12.12: Categorized Symbolizing options
82
Gambar 12.13: Graduated Symbolizing options
Bab 12. Pekerjaan dengan Data Vektor
QGIS User Guide, Rilis 2.6
• 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
shows the graduated rendering dialog for the rivers layer of the QGIS sample dataset.
Tip: 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
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
). 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.
Tip: 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.
12.3. The Vector Properties Dialog 83
QGIS User Guide, Rilis 2.6
Gambar 12.14: Rule-based Symbolizing options
84
Gambar 12.15: Point displacement dialog
Bab 12. Pekerjaan dengan Data Vektor
QGIS User Guide, Rilis 2.6
Gambar 12.16: Inverted Polygon dialog
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.
Tip: 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
12.3. The Vector Properties Dialog 85
QGIS User Guide, Rilis 2.6
Gambar 12.17: Color picker ramp tab
Gambar 12.18: Color picker swatcher tab
86
Gambar 12.19: Quick color picker menu
Bab 12. Pekerjaan dengan Data Vektor
QGIS User Guide, Rilis 2.6
precise 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
12.3. The Vector Properties Dialog 87
QGIS User Guide, Rilis 2.6
• Rendering
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
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
). 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
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
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
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
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
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.
88 Bab 12. Pekerjaan dengan Data Vektor
QGIS User Guide, Rilis 2.6
Gambar 12.20: Smart labeling of vector point layers
The Buffer menu has the same functions as described in section
The Background menu has the same entries as described in section
Also, the Shadow menu has the same entries as described in section
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
).
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
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.
12.3. The Vector Properties Dialog 89
QGIS User Guide, Rilis 2.6
Gambar 12.21: Smart labeling of vector line layers
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.
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
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, are possible.
Above line , On line , Below line and Line orientation dependent position
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
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"
90 Bab 12. Pekerjaan dengan Data Vektor
QGIS User Guide, Rilis 2.6
Gambar 12.22: Smart labeling of vector polygon layers
Gambar 12.23: Using expressions for labeling
12.3. The Vector Properties Dialog 91
QGIS User Guide, Rilis 2.6
-> John Smith, Paris
# label based on two fields ’name’ and ’place’ separated by comma
’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
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
).
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
). 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:
92 Bab 12. Pekerjaan dengan Data Vektor
QGIS User Guide, Rilis 2.6
Gambar 12.24: Labeling of vector polygon layers with data-defined override
12.3. The Vector Properties Dialog
Gambar 12.25: Move labels
93
QGIS User Guide, Rilis 2.6
94
Gambar 12.26: Dialog to select an edit widget for an attribute column
Bab 12. Pekerjaan dengan Data Vektor
QGIS User Guide, Rilis 2.6
• Checkbox : Displays a checkbox, and you can define what attribute is added to the column when the checkbox is activated or not.
•
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
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. The Vector Properties Dialog 95
QGIS User Guide, Rilis 2.6
Gambar 12.27: Dialog to create categories with the
Attribute editor layout
96
Gambar 12.28: Resulting built-in form in a data entry session
Bab 12. Pekerjaan dengan Data Vektor
QGIS User Guide, Rilis 2.6
12.3.4 General Menu
Use this menu to make general settings for the vector layer. There are several options available:
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
Gambar 12.29: General menu in vector layers properties dialog
12.3. The Vector Properties Dialog 97
QGIS User Guide, Rilis 2.6
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
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.
Gambar 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).
98 Bab 12. Pekerjaan dengan Data Vektor
Gambar 12.31: Map tip made with HTML code
QGIS User Guide, Rilis 2.6
Gambar 12.32: Overview action dialog with some sample actions
12.3. The Vector Properties Dialog 99
QGIS User Guide, Rilis 2.6
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
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
100 Bab 12. Pekerjaan dengan Data Vektor
QGIS User Guide, Rilis 2.6
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:
Gambar 12.33: Select feature and choose action
12.3. The Vector Properties Dialog 101
QGIS User Guide, Rilis 2.6
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
102 Bab 12. Pekerjaan dengan Data Vektor
QGIS User Guide, Rilis 2.6
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
Gambar 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
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
12.3. The Vector Properties Dialog 103
QGIS User Guide, Rilis 2.6
Gambar 12.35: Vector properties dialog with diagram menu
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.
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.
104 Bab 12. Pekerjaan dengan Data Vektor
QGIS User Guide, Rilis 2.6
Gambar 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
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
12.4. Expressions 105
QGIS User Guide, Rilis 2.6
Gambar 12.37: Metadata menu in vector layers properties dialog commonly used operators, see Operators .
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
106 Bab 12. Pekerjaan dengan Data Vektor
QGIS User Guide, Rilis 2.6
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
12.4. Expressions 107
QGIS User Guide, Rilis 2.6
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.
$now age year month current date and time difference between two dates extract the year part from a date, or the number of years from an interval extract the month part from a date, or the number of months from an interval
108 Bab 12. Pekerjaan dengan Data Vektor
QGIS User Guide, Rilis 2.6
week day hour minute second extract the week number from a date, or the number of weeks from an interval extract the day from a date, or the number of days from an interval extract the hour from a datetime or time, or the number of hours from an interval extract the minute from a datetime or time, or the number of minutes from an interval extract the second from a datetime or time, or the number of minutes from an interval
Some example:
• Get the month and the year of today in the format “10/2014” month($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.
12.4. Expressions 109
QGIS User Guide, Rilis 2.6
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
110 Bab 12. Pekerjaan dengan Data Vektor
QGIS User Guide, Rilis 2.6
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.
12.4. Expressions 111
QGIS User Guide, Rilis 2.6
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.
Catatan: The procedure for editing GRASS layers is different - see section
Digitizing and editing a GRASS vector layer
for details.
Tip: 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
).
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
112 Bab 12. Pekerjaan dengan Data Vektor
QGIS User Guide, Rilis 2.6
Gambar 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.
12.5. Editing 113
QGIS User Guide, Rilis 2.6
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
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.
Tip: Save Regularly
Remember to
Save Layer Edits regularly. This will also check that your data source can accept all the changes.
114 Bab 12. Pekerjaan dengan Data Vektor
QGIS User Guide, Rilis 2.6
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.
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 .
Gambar 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.
Tip: 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 you made in multiple layers. You also have the opportunity to
Save for Selected Layers to save all changes
Rollback for Selected Layers , so that the
Cancel digitization may be withdrawn for all selected layers. If you want to stop editing the selected layers, for Selected 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.
12.5. Editing 115
QGIS User Guide, Rilis 2.6
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
Tip: 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
116 Bab 12. Pekerjaan dengan Data Vektor
QGIS User Guide, Rilis 2.6
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.
Tip: 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 in-memory state is preserved. This allows you to adjust your edits and try again.
Tip: 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.
12.5. Editing 117
QGIS User Guide, Rilis 2.6
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.
Gambar 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
118 Bab 12. Pekerjaan dengan Data Vektor
QGIS User Guide, Rilis 2.6
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 multi-part 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
12.5. Editing 119
QGIS User Guide, Rilis 2.6
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.
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.
Catatan: 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.
120 Bab 12. Pekerjaan dengan Data Vektor
QGIS User Guide, Rilis 2.6
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.
Gambar 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.
Catatan:
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
above.
12.5. Editing 121
QGIS User Guide, Rilis 2.6
Gambar 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
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 an autoincrementing primary key .
[Specify CRS] . If desired, you can select Create
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
above.
Further management of SpatiaLite layers can be done with the DB Manager. See
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.
122 Bab 12. Pekerjaan dengan Data Vektor
QGIS User Guide, Rilis 2.6
12.5. Editing
Gambar 12.43: Creating a New SpatiaLite layer Dialog
123
QGIS User Guide, Rilis 2.6
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
of features and the number of selected features are shown in the attribute table title.
Gambar 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
regions that are boroughs from regions.shp
of the QGIS sample data, you have to open the Fields and Values
124 Bab 12. Pekerjaan dengan Data Vektor
QGIS User Guide, Rilis 2.6
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:
"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
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
Tip: 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
Legenda Peta ). 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
12.5. Editing 125
QGIS User Guide, Rilis 2.6
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
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.
Gambar 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).
126 Bab 12. Pekerjaan dengan Data Vektor
QGIS User Guide, Rilis 2.6
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.
12.5. Editing
Gambar 12.46: Relation Manager
127
QGIS User Guide, Rilis 2.6
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.
Gambar 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.
128 Bab 12. Pekerjaan dengan Data Vektor
QGIS User Guide, Rilis 2.6
Gambar 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.
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.
Gambar 12.49: Query Builder
The Fields list contains all attribute columns of the attribute table to be searched. To add an attribute column to
12.6. Query Builder 129
QGIS User Guide, Rilis 2.6
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.
Tip: 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.
130 Bab 12. Pekerjaan dengan Data Vektor
QGIS User Guide, Rilis 2.6
12.7. Field Calculator
Gambar 12.50: Field Calculator
131
QGIS User Guide, Rilis 2.6
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
chapter.
132 Bab 12. Pekerjaan dengan Data Vektor
BAB
13
Pekerjaan dengan Data Raster
.
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
Literatur dan Referensi Web ).
A complete list is available at http://www.gdal.org/formats_list.html
.
Catatan: 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
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.
133
QGIS User Guide, Rilis 2.6
.
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
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.
134 Bab 13. Pekerjaan dengan Data Raster
QGIS User Guide, Rilis 2.6
Gambar 13.1: Raster Layers Properties Dialog
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)
13.2. Raster Properties Dialog 135
QGIS User Guide, Rilis 2.6
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’.
Gambar 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.
Tip: 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
Catatan: 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.
136 Bab 13. Pekerjaan dengan Data Raster
QGIS User Guide, Rilis 2.6
Gambar 13.3: Raster Renderer - Paletted
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 .
Gambar 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
13.2. Raster Properties Dialog 137
QGIS User Guide, Rilis 2.6
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:
Gambar 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
138 Bab 13. Pekerjaan dengan Data Raster
QGIS User Guide, Rilis 2.6
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
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.
Gambar 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:
13.2. Raster Properties Dialog 139
QGIS User Guide, Rilis 2.6
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 transparency settings and applies them to the current raster layer.
Import from file loads your
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 .
140 Bab 13. Pekerjaan dengan Data Raster
QGIS User Guide, Rilis 2.6
Gambar 13.7: The Pyramids Menu
13.2. Raster Properties Dialog
Gambar 13.8: Raster Histogram
141
QGIS User Guide, Rilis 2.6
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.
Gambar 13.9: Raster Metadata
.
13.3 Kalkulator Raster
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.
Daftar
Pita Raster berisi semua lapisan raster yang dapat digunakan. Untuk menambahkan raster ke kalkulator raster kolom ekspresi, klik dua kali namanya dalam daftar kolom. Anda kemudian dapat menggunakan operator untuk membangun perhitungan ekspresi, atau Anda hanya dapat mengetik mereka ke dalam kotak.
Dalam bagian Hasil lapisan , Anda akan perlu mendefinisikan keluaran lapisan. Anda kemudian dapat menentukan luasnya daerah perhitungan berdasarkan masukan lapisan raster, atau berdasarkan koordinat X, Y dan pada kolom dan baris, untuk mengatur resolusi dari keluaran lapisan. Jika lapisan masukan memiliki resolusi yang berbeda, nilai-nilai akan resampled dengan algoritma tetangga terdekat.
Bagian Operator berisi semua operator yang tersedia. Untuk menambahkan operator ke kotak ekspresi kalkulator raster, klik tombol yang sesuai. Perhitungan matematika tersedia (
+
,
-
,
*
, ... ) dan fungsi trigonometri ( sin
, cos
, tan
, ... ). Nantikan operator lainnya yang akan datang!
Dengan kotak centang Tambahkan hasil ke proyek , lapisan hasil secara otomatis akan ditambahkan ke area legenda dan dapat divisualisasikan.
13.3.1 Contoh-contoh
Konversi nilai elevasi dari meter ke kaki
Membuat elevasi raster dalam kaki dari raster dalam meter, Anda perlu menggunakan faktor konversi meter ke kaki: 3.28. Ekspresinya adalah:
142 Bab 13. Pekerjaan dengan Data Raster
QGIS User Guide, Rilis 2.6
Gambar 13.10: Kalkulator Raster
*
3.28
Menggunakan masker
Jika Anda ingin untuk menutupi bagian-bagian dari suatu raster - kata, misalnya, karena Anda hanya tertarik pada ketinggian di atas 0 meter – Anda dapat menggunakan ekspresi berikut untuk membuat masker dan menerapkan hasil untuk raster dalam satu langkah.
( "[email protected]" >= 0 )
*
Dengan kata lain, untuk setiap sel yang lebih besar dari atau sama dengan 0, atur nilainya ke 1. Jika nilai ke 0. Ini menciptakan masker 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.
13.3. Kalkulator Raster 143
QGIS User Guide, Rilis 2.6
144 Bab 13. Pekerjaan dengan Data Raster
BAB
14
Pekerjaan dengan Data OGC
.
14.1 QGIS sebagai OGC Klien Data
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/ .
Spesifikasi penting OGC yang didukung oleh QGIS adalah:
• WMS
— Web Map Service ( Klien WMS/WMTS )
• WMTS
— Web Map Tile Service ( Klien WMS/WMTS )
• WFS
— Web Feature Service ( Klien WFS dan WFS-T )
•
WFS-T
— Web Feature Service - Transactional ( Klien WFS dan WFS-T )
• WCS
• SFS
• 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
14.1.1 Klien WMS/WMTS
Sekilas Dukungan WMS
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.
145
QGIS User Guide, Rilis 2.6
Lapis WMS dapat ditambahkan dengan sederhana, asalkan Anda tahu mengakses URL server WMS, Anda memiliki sambungan ke server, dan server memahami HTTP sebagai mekanisme transportasi data.
Sekilas Dukungan WMTS
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.
Dalam rangka untuk menampilkan data pada berbagai skala dengan apa yang pengguna inginkan, WMTS tile sets diproduksi pada beberapa tingkat skala yang berbeda dan dibuat tersedia untuk klien GIS untuk meminta mereka.
Diagram ini menggambarkan konsep tile sets:
Gambar 14.1: Konsep 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
.
Catatan: 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.
146 Bab 14. Pekerjaan dengan Data OGC
QGIS User Guide, Rilis 2.6
When you read WMTS, you can often think WMS-C also.
Memilih Server WMS/WMTS
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
Nama A name for this connection. This name will be used in the Server Connections drop-down
URL 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.
Nama pengguna Username to access a secured WMS server. This parameter is optional.
Kata Sandi Password for a basic authenticated WMS server. This parameter is optional.
Ignore GetMap URI reported in capabilities . Use given URI from URL field above.
Abaikan
GetMap URI
Abaikan
GetFeatureInfo
URI
Ignore GetFeatureInfo URI reported in capabilities above.
. Use given URI from URL field
Tabel OGC 1: Parameter Sambungan WMS
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.
Tip: Di URL Server WMS
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.
Memuat Lapis WMS/WMTS
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.
Layar Anda sekarang terlihat seperti
figure_OGR_1 , yang menunjukkan respon yang diberikan oleh server DM
Solutions Group WMS.
Pengkodean Gambar
The Image encoding section lists the formats that are supported by both the client and server. Choose one depending on your image accuracy requirements.
Tip: Pengkodean Gambar
Anda biasanya akan menemukan bahwa server WMS menawarkan pilihan pengkodean JPEG atau PNG. JPEG adalah format kompresi lossy, sedangkan PNG mereproduksi data raster mentah.
14.1. QGIS sebagai OGC Klien Data 147
QGIS User Guide, Rilis 2.6
148
Gambar 14.2: Dialog menambahkan server WMS, menunjukkan lapis yang tersedia
Bab 14. Pekerjaan dengan Data OGC
QGIS User Guide, Rilis 2.6
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.
Opsi-Opsi
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.
Feature limit for GetFeatureInfo mendefinisikan fitur apa dari server untuk 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.
Urutan Lapis
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.
Tip: Mengurutkan Lapis WMS
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.
Transparansi
In this version of QGIS, the Global transparency setting from the Layer Properties is hard coded to be always on, where available.
Tip: Transparansi Lapis WMS
Ketersediaan gambar WMS transparansi tergantung pada pengkodean gambar yang digunakan: PNG dan GIF didukung transparansi, JPEG sementara tidak didukung.
Sistem Referensi Koordinat
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
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.
Mencari server
Within QGIS, you can search for WMS servers.
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
14.1. QGIS sebagai OGC Klien Data 149
QGIS User Guide, Rilis 2.6
Gambar 14.3: Dialog untuk mencari server WMS dengan beberapa kata kunci 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
.
Tileset
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.
Menggunakan Alat Identifikasi
Setelah Anda telah menambahkan server WMS, dan jika ada lapis dari server WMS adalah queryable, Anda kemudian dapat menggunakan alat
Identify untuk memilih pixel di peta kanvas. Sebuah query dibuat untuk server WMS untuk setiap pilihan yang dibuat. Hasil dari query dikembalikan dalam teks biasa. Format teks ini tergantung pada server WMS tertentu yang digunakan.
Pemilihan Format
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.
Dukungan format
GML
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
150 Bab 14. Pekerjaan dengan Data OGC
QGIS User Guide, Rilis 2.6
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"
Menampilkan Properti
Once you have added a WMS server, you can view its properties by right-clicking on it in the legend and selecting
Properties .
Tab Metadata
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
Literatur dan Referensi Web ), but here are a few handy definitions:
• Properti Server
– Versi WMS — Versi WMS yang didukung oleh 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.
• Properti Lapis
– Dipilih — Apakah ada atau tidak lapis ini dipilih ketika server telah ditambahkan ke dalam proyek ini.
– Visible — Whether or not this layer is selected as visible in the legend (not yet used in this version of
QGIS).
– Bisa Diidentifikasi — Apakah ada atau tidak lapis ini akan menghasilkan apa-apa ketika Mengidentifikasi alat yang digunakan di atasnya.
– 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
14.1. QGIS sebagai OGC Klien Data 151
QGIS User Guide, Rilis 2.6
for a result.
– 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.
Batasan Klien WMS
Not all possible WMS client functionality had been included in this version of QGIS. Some of the more noteworthy exceptions follow.
Pengaturan Mengedit Lapis WMS
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
Server WMS Membutuhkan Otentikasi
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
for details.
Tip: Mengakses OGC-lapis dengan aman
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
.
Tip: 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 sebagai OGC Data Server .
152 Bab 14. Pekerjaan dengan Data OGC
QGIS User Guide, Rilis 2.6
14.1.2 Klien WCS
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 Klien WFS dan WFS-T
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.
Memuat Lapis WFS
As an example, we use the DM Solutions WFS server and display a layer.
http://www2.dmsolutions.ca/cgi-bin/mswfs_gmap
The URL is:
1. Click on the
2. Klik [Baru] .
Add WFS Layer tool on the Layers toolbar. The Add WFS Layer from a Server dialog appears.
3. Masukkan ‘DM Solutions’ sebagai nama.
4. Masukkan URL (lihat di atas).
5. Klik [OK] .
6. Pilh ‘DM Solutions’ dari daftar drop-down
Sambungan Server
7. Klik [Sambung] .
8. Wait for the list of layers to be populated.
9. Select the Parks layer in the list.
.
10. Klik [Terapkan] untuk menambahkan lapis ke peta.
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
for further information about the mailing lists.
Tip: Mencari Server WFS
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.
14.1. QGIS sebagai OGC Klien Data 153
QGIS User Guide, Rilis 2.6
Gambar 14.4: Menambahkan lapis WFS
14.2 QGIS sebagai OGC Data Server
Server QGIS merupakan open source WMS 1.3, WFS 1.0.0 dan WCS 1 1.1.1 implementasi yang, di samping itu, mengimplementasikan fitur kartografi canggih untuk pemetaan tematik. Server QGIS adalah aplikasi FastC-
GI/CGI (Common Gateway Interface) ditulis dalam C++ yang bekerja sama dengan web server (misalnya Apache,
Lighttpd). Hal ini didanai oleh proyek Uni Eropa Orchestra, Sany dan kota Uster di Swiss.
Server QGIS digunakan QGIS sebagai back end untuk logika GIS dan peta rendering. Selain itu, perpustakaan
Qt digunakan untuk grafis dan pemrograman C++ platform-independen. Berbeda dengan perangkat lunak WMS lain, Server QGIS menggunakan aturan kartografi sebagai bahasa konfigurasi, baik untuk konfigurasi server dan aturan kartografi yang ditetapkan pengguna.
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.
Dalam salah satu buku pedoman berikut, kami akan memberikan contoh konfigurasi untuk membangun sebuah
Server QGIS. Untuk saat ini, kami sarankan untuk membaca salah satu URL berikut ini untuk mendapatkan informasi lebih lanjut:
• 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 Contoh Pemasangan pada Debian Squeeze
Pada titik ini, kami akan memberikan contoh instalasi singkat dan sederhana bagaimana caranya untuk Debian
Squeeze. Banyak OS lain menyediakan paket untuk Server QGIS, juga. Jika Anda harus membangun semuanya dari sumber, silakan lihat URL di atas.
Terlepas dari QGIS dan Server QGIS, Anda memerlukan server web, dalam kasus apache2 kami. Anda dapat menginstal semua paket dengan aptitude atau apt-get install bersama-sama dengan paket ketergantungan yang diperlukan lainnya. Setelah instalasi, Anda harus menguji mengkonfirmasi bahwa server web dan Server
QGIS bekerja seperti yang diharapkan. Pastikan server apache berjalan dengan
/ etc/init.d/apache2 start
. Buka peramban web dan ketik URL: http://localhost
. Jika apache sudah habis, Anda akan melihat pesan ‘It works!’.
154 Bab 14. Pekerjaan dengan Data OGC
QGIS User Guide, Rilis 2.6
Sekarang menunjukkan coba pemasangan batas-batas negara
Server
/usr/lib/cgi-bin/qgis_mapserv.fcgi
bagian
QGIS.
dan
Alaska.
qgis_mapserv.fcgi
mendukung standar tersedia
WMS di yang
Tambahkan WMS dengan URL http://localhost/cgi-bin/qgis_mapserv.fcgi
seperti yang dijelaskan dalam
Gambar 14.5: WMS standar dengan batas-batas Amerika Serikat termasuk dalam QGIS Server (KDE)
14.2.2 Membuat WMS/WFS/WCS dari proyek QGIS
Untuk memberikan Server QGIS baru WMS, WFS atau WCS, kita harus membuat berkas proyek QGIS dengan beberapa data. Di sini, kita menggunakan ‘Alaska’ shapefile dari contoh dataset QGIS. Tentukan warna dan gaya dari lapis dalam QGIS dan proyek CRS, jika belum ditetapkan.
Kemudian, ke menu Server OWS dialog Proyek
→
Proyek Properti dan memberikan beberapa informasi tentang
OWS di kolom di bawah Kemapuan Layanan . Ini akan muncul di GetCapabilities respon dari WMS, WFS atau
WCS. Jika Anda tidak mencentang Kemampuan Layanan , Server QGIS akan menggunakan informasi yang diberikan dalam berkas wms_metadata.xml
yang terletak di folder cgi-bin
.
Kemampuan WMS
Di bagian Kemampuan WMS , Anda dapat menentukan tingkat diiklankan di respon WMS GetCapabilities dengan memasukkan nilai minimum dan maksimum X dan Y dalam kolom di bawah Batas diiklankan . Klik Gunakan
Batas Kanvas Sekarang menetapkan nilai-nilai ini sejauh yang sedang ditampilkan dalam kanvas peta QGIS.
Dengan mencentang Pembatasan CRS , Anda dapat membatasi di mana sistem koordinat referensi (CRS)
Server QGIS akan menawarkan untuk membuat peta. Gunakan tombol di bawah untuk memilih CRS dari
14.2. QGIS sebagai OGC Data Server 155
QGIS User Guide, Rilis 2.6
156
Gambar 14.6: Definisi QGIS Server WMS/WFS/WCS proyek (KDE)
Bab 14. Pekerjaan dengan Data OGC
QGIS User Guide, Rilis 2.6
Coordinate Reference System Selector, atau klik Digunakan untuk menambahkan CRS digunakan proyek QGIS ke dalam daftar.
Jika Anda memiliki penyusun cetak didefinisikan dalam proyek Anda, mereka akan tercantum dalam GetCapabilities respon, dan mereka dapat digunakan oleh permintaan GetPrint untuk membuat cetakan, menggunakan salah satu tata letak penyusun cetak sebagai template. Ini adalah ekstensi-khusus QGIS untuk spesifikasi WMS
1.3.0. Jika Anda ingin mengecualikan penyusun cetak dari yang diterbitkan oleh WMS, centang Kecuali
Penyusun dan klik tombol dibawah . Kemudian, pilih penyusun cetak dari dialog Pilih penyusun cetak untuk menambahkannya ke daftar penyusun yang dikecualikan.
Jika Anda ingin mengecualikan setiap lapis atau grup lapis dari yang diterbitkan oleh WMS, centang Kecuali
Lapis dan klik menu di bawah . Akan membuka dialog Pilih lapis dan grup dibatasi , yang memungkinkan
Anda untuk memilih lapis dan grup yang tidak ingin dipublikasikan. Gunakan tombol
Shift atau
Ctrl jika
Anda ingin memilih beberapa entri sekaligus.
Anda dapat menerima diminta GetFeatureInfo sebagai teks biasa, XML dan GML. Default adalah XML, teks atau format GML tergantung format keluaran dipilih untuk permintaan GetFeatureInfo.
Jika Anda ingin, Anda dapat mencentang Tambahkan geometri untuk fitur respon . Ini akan mencakup dalam respon GetFeatureInfo fitur geometri dalam format teks. Jika Anda ingin QGIS Server QGIS mengiklankan
URL permintaan khusus dalam respon WMS GetCapabilities, masukkan URL yang sesuai dalam kolom Iklankan
URL . Selanjutnya, Anda dapat membatasi ukuran maksimum peta dikembalikan oleh permintaan GetMap dengan memasukkan lebar, tinggi dalam kolom masing-masing di bawah Maksimal untuk permintaan GetMap .
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.
Kemampuan WFS dalam area Kemampuan WFS , Anda dapat memilih lapis yang ingin Anda publikasikan sebagai WFS, dan menentukan apakah mereka akan memungkinkan memperbarui, memasukkan dan menghapus operasi. Jika Anda memasukkan URL di kolom Iklankan URL dari bagian Kemampuan WFS , Server QGIS akan mengiklankan URL tertentu dalam respon WFS GetCapabilities.
Kemampuan WCS dalam area Kemampuan WCS , Anda dapat memilih lapis yang ingin Anda publikasikan sebagai WCS. Jika Anda memasukkan URL di kolom Iklankan URL dari bagian Kemampuan WCS , Server QGIS akan mengiklankan URL tertentu dalam respon WCS GetCapabilities.
Sekarang, simpan sesi ke dalam berkas proyek alaska.qgs
. Untuk memberikan proyek sebagai WMS / WFS, kita membuat folder baru
/usr/lib/cgi-bin/project dengan hak istimewa admin dan menambahkan berkas proyek alaska.qgs
dan salinan berkas qgis_mapserv.fcgi
- itu saja.
Sekarang coba proyek kita WMS, WFS dan WCS. Tambahkan WMS, WFS dan WCS seperti yang dijelaskan dalam
dan
ke QGIS dan muat data. URLnya adalah: http://localhost/cgi-bin/project/qgis_mapserv.fcgi
Menyetel baik OWS Anda
Untuk lapis vektor, menu Kolom dari dialog Lapis
→
Properti memungkinkan Anda untuk menentukan setiap atribut jika akan diterbitkan atau tidak. Secara default, semua atribut yang diterbitkan oleh WMS dan WFS. Jika
Anda ingin atribut tertentu tidak akan diterbitkan, hapus centang pada kotak centang yang sesuai dalam kolom
WMS atau WFS .
Anda dapat melapisi tanda air pada peta yang diproduksi oleh WMS Anda dengan menambahkan penjelasan teks atau anotasi SVG ke berkas proyek. Lihat bagian Alat Anotasi di
untuk petunjuk membuat anotasi. Untuk anotasi yang akan ditampilkan sebagai tanda air pada keluaran WMS, kotak centang Posisi peta
14.2. QGIS sebagai OGC Data Server 157
QGIS User Guide, Rilis 2.6
ditetapkan dalam dialog Anotasi teks harus dilepas centangnya. Hal ini dapat diakses dengan mengklik ganda anotasi sementara salah satu alat anotasi aktif. Untuk anotasi SVG, Anda akan membutuhkan mengatur proyek menyimpan path absolut (dalam menu Umum dari dialog Proyek
→
Proyek Properti ) atau secara manual mengubah path ke gambar SVG dengan cara itu, path relatif valid.
Parameter tambahan yang didukung oleh permintaan WMS GetMap
Dalam permintaan WMS GetMap, Server QGIS menerima beberapa parameter tambahan di samping parameter standar sesuai dengan spesifikasi OCG WMS 1.3.0:
• Parameter MAP : Mirip dengan MapServer, parameter ‘MAP‘ dapat digunakan untuk menentukan path ke berkas proyek QGIS. Anda dapat menentukan path absolut atau path relatif ke lokasi server executable
( qgis_mapserv.fcgi
). Jika tidak ditentukan, pencarian server QGIS untuk berkas .qgs dalam direktori di mana server executable berada.
Contoh: http://localhost/cgi-bin/qgis_mapserv.fcgi?\
REQUEST=GetMap&MAP=/home/qgis/mymap.qgs&...
• Parameter DPI : Parameter
DPI dapat digunakan untuk menentukan resolusi keluaran yang diminta.
Contoh: http://localhost/cgi-bin/qgis_mapserv.fcgi?REQUEST=GetMap&DPI=300&...
• Parameter Kekeruhan : Opacity dapat diatur pada lapis atau tingkat grup. Nilai diperbolehkan berkisar dari
0 (sepenuhnya transparan) sampai 255 (sepenuhnya keruh).
Contoh: 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).
Contoh:
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.
158 Bab 14. Pekerjaan dengan Data OGC
QGIS User Guide, Rilis 2.6
.
Environment variables
• QGIS_OPTIONS_PATH : The variable specifies path to directory with settings.
the same ways as QGIS application –optionspath option.
It works
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/"
14.2. QGIS sebagai OGC Data Server 159
QGIS User Guide, Rilis 2.6
160 Bab 14. Pekerjaan dengan Data OGC
BAB
15
Pekerjaan dengan Data GPS
.
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
for more information about the sample data.
1. Select Vector
→
GPS
→
GPS Tools or click the tab (see
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.
161
QGIS User Guide, Rilis 2.6
Gambar 15.1: The GPS Tools dialog window
Catatan: 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
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
.
162 Bab 15. Pekerjaan dengan Data GPS
QGIS User Guide, Rilis 2.6
Gambar 15.2: The download tool
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.
15.1. GPS Plugin 163
QGIS User Guide, Rilis 2.6
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
Catatan: 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
164 Bab 15. Pekerjaan dengan Data GPS
QGIS User Guide, Rilis 2.6
Ubuntu/Mint GNU/Linux
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
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.
Peringatan: 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.
15.2. Live GPS tracking 165
QGIS User Guide, Rilis 2.6
Gambar 15.3: GPS tracking position and additional attributes
166
Gambar 15.4: GPS tracking signal strength
Bab 15. Pekerjaan dengan Data GPS
QGIS User Guide, Rilis 2.6
Gambar 15.5: GPS tracking polar window
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 .
15.2. Live GPS tracking 167
QGIS User Guide, Rilis 2.6
168
Gambar 15.6: GPS tracking options window
Bab 15. Pekerjaan dengan Data GPS
QGIS User Guide, Rilis 2.6
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
15.2. Live GPS tracking 169
QGIS User Guide, Rilis 2.6
gpsd / dev / rfcomm0
.
or without it, by connecting the QGIS live tracking tool directly to the device (for example /dev/rfcomm0 ).
170 Bab 15. Pekerjaan dengan Data GPS
BAB
16
GRASS GIS Integration
•
•
•
•
•
•
•
•
•
•
The GRASS plugin provides access to GRASS GIS databases and functionalities (see GRASS-PROJECT in
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
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
GRASS LOCATION ) and import some raster and vector data (see section
Importing data into a GRASS LOCA-
TION ) for further analysis with the GRASS Toolbox (see section
171
QGIS User Guide, Rilis 2.6
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
Contoh 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
(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/ .
Tip: 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
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
Literatur dan Referensi Web ). 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
172 Bab 16. GRASS GIS Integration
QGIS User Guide, Rilis 2.6
Gambar 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
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
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
) or to create a new ure_grass_location_2 ).
LOCATION altogether. Select
Create new location
(see
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
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
Literatur dan Referensi Web ).
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.
16.3. GRASS LOCATION and MAPSET 173
QGIS User Guide, Rilis 2.6
16. Notice that some of the tools in the GRASS toolbar that were disabled are now enabled.
Gambar 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
can also use the already-existing vector and raster data in the sample GRASS
LOCATION
‘alaska’, included in the QGIS ‘Alaska’ dataset
Contoh data , and move on to section
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
Literatur dan Referensi Web , and section
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 click [Next] .
altogether. Click on the radio button Select location (see
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
174 Bab 16. GRASS GIS Integration
QGIS User Guide, Rilis 2.6
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 appears.
Open GRASS tools icon. The GRASS Toolbox (see section
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.
16.5. The GRASS vector data model 175
QGIS User Guide, Rilis 2.6
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.
Tip: 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
Tip: 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
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
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.
Tip: 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
you see the GRASS digitizing toolbar icons provided by the
GRASS plugin.
Table
explains the available functionalities.
Gambar 16.3: GRASS Digitizing Toolbar
176 Bab 16. GRASS GIS Integration
QGIS User Guide, Rilis 2.6
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.
Gambar 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.
16.7. Digitizing and editing a GRASS vector layer 177
QGIS User Guide, Rilis 2.6
• Field (layer) - Each geometry element can be connected with several attribute tables using different GRASS geometry layers. The default layer number is 1.
Tip: 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.
Gambar 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).
Gambar 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 ).
Tip: GRASS Edit Permissions
178 Bab 16. GRASS GIS Integration
QGIS User Guide, Rilis 2.6
Gambar 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
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.
16.8. The GRASS region tool 179
QGIS User Guide, Rilis 2.6
Gambar 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
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
.
Tip: 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.
180 Bab 16. GRASS GIS Integration
QGIS User Guide, Rilis 2.6
Gambar 16.9: GRASS Toolbox Module Options
16.9. The GRASS Toolbox
Gambar 16.10: GRASS Toolbox Module Output
181
QGIS User Guide, Rilis 2.6
Gambar 16.11: GRASS Toolbox Module Manual
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
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
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
182 Bab 16. GRASS GIS Integration
QGIS User Guide, Rilis 2.6
their 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 small-scale map, so the detail is unnecessary.
Tip: 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.
Gambar 16.12: GRASS module v.generalize to smooth a vector map
Tip: Other uses for r.contour
16.9. The GRASS Toolbox 183
QGIS User Guide, Rilis 2.6
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).
184 Bab 16. GRASS GIS Integration
QGIS User Guide, Rilis 2.6
Gambar 16.13: The GRASS shell, r.shaded.relief module
Gambar 16.14: Displaying shaded relief created with the GRASS module r.shaded.relief
16.9. The GRASS Toolbox 185
QGIS User Guide, Rilis 2.6
• 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
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
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).
Gambar 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
186 Bab 16. GRASS GIS Integration
QGIS User Guide, Rilis 2.6
•
•
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 .
16.9. The GRASS Toolbox 187
QGIS User Guide, Rilis 2.6
188 Bab 16. GRASS GIS Integration
BAB
17
QGIS kerangka pengolahan
.
17.1 Pengantar
Bab ini memperkenalkan kerangka pengolahan QGIS, lingkungan geoprocessing yang dapat digunakan untuk memanggil algoritma asli dan pihak ketiga dari QGIS, membuat tugas analisis spasial Anda lebih produktif dan mudah untuk melakukannya.
Pada bagian berikut kita akan meninjau bagaimana menggunakan unsur-unsur grafis dari kerangka kerja ini dan mengambil yang terbaik masing-masing dari mereka.
Ada empat elemen dasar dalam kerangka GUI, yang digunakan untuk menjalankan algoritma untuk tujuan yang berbeda. Memilih salah satu alat atau lain akan tergantung pada jenis analisis yang akan dilakukan dan karakteristik tertentu dari masing-masing pengguna dan proyek. Semuanya (kecuali untuk antarmuka batch processing, yang disebut dari toolbox, seperti akan kita lihat) bisa diakses dari menu Pengolahan (Anda akan melihat lebih dari empat entri. Yang tersisa tidak digunakan untuk mengeksekusi algoritma dan akan dijelaskan nanti dalam bab ini).
• Toolbox. Unsur utama dari GUI, digunakan untuk menjalankan algoritma tunggal atau menjalankan proses batch berdasarkan algoritma tersebut.
Gambar 17.1: Toolbox Pengolahan
189
QGIS User Guide, Rilis 2.6
• Modeler grafis. Beberapa algoritma dapat dikombinasikan secara grafis dengan menggunakan modeler untuk mendefinisikan alur kerja, menciptakan satu proses yang melibatkan beberapa sub-proses
Gambar 17.2: Modeler Pengolahan
.
• Sejarah pengelola. Semua tindakan dilakukan dengan menggunakan salah satu elemen tersebut disimpan dalam berkas sejarah dan dapat kemudian dengan mudah direproduksi menggunakan manajer sejarah
• Antarmuka pengolahan batch. Antarmuka ini memungkinkan Anda untuk menjalankan proses batch dan mengotomatisasi eksekusi algoritma tunggal pada beberapa dataset.
Dalam bagian berikut ini, kita akan meninjau masing-masing elemen ini secara rinci.
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:
190 Bab 17. QGIS kerangka pengolahan
QGIS User Guide, Rilis 2.6
Gambar 17.3: Pengolahan Sejarah
17.2. The toolbox
Gambar 17.4: Antarmuka proses batch
191
QGIS User Guide, Rilis 2.6
Gambar 17.5: Processing Toolbox
192
Gambar 17.6: Processing Toolbox (advanced mode)
Bab 17. QGIS kerangka pengolahan
QGIS User Guide, Rilis 2.6
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).
Gambar 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-
17.2. The toolbox 193
QGIS User Guide, Rilis 2.6
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.
Gambar 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.
194
Gambar 17.9: Number Selector
• A range, with min and max values to be introduced in two text boxes.
Bab 17. QGIS kerangka pengolahan
QGIS User Guide, Rilis 2.6
• 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.
Gambar 17.10: Extent selector
If you select the first option, you will see a window like the next one.
Gambar 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.
Gambar 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.
17.2. The toolbox 195
QGIS User Guide, Rilis 2.6
Gambar 17.13: Multiple Selection
196
Gambar 17.14: Fixed Table
Bab 17. QGIS kerangka pengolahan
QGIS User Guide, Rilis 2.6
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.
17.2. The toolbox 197
QGIS User Guide, Rilis 2.6
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.
198 Bab 17. QGIS kerangka pengolahan
QGIS User Guide, Rilis 2.6
Gambar 17.15: Rendering Styles
.
•
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
17.3. The graphical modeler 199
QGIS User Guide, Rilis 2.6
Gambar 17.16: Modeler
• 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.
200 Bab 17. QGIS kerangka pengolahan
Gambar 17.17: Model Parameters
Gambar 17.18: Model Parameters
QGIS User Guide, Rilis 2.6
17.3. The graphical modeler
Gambar 17.19: Model Parameters
201
QGIS User Guide, Rilis 2.6
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.
Gambar 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
202 Bab 17. QGIS kerangka pengolahan
QGIS User Guide, Rilis 2.6
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:
17.3. The graphical modeler
Gambar 17.21: Modeler Right Click
203
QGIS User Guide, Rilis 2.6
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:
Gambar 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.
Gambar 17.23: Help Edition
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.
204 Bab 17. QGIS kerangka pengolahan
QGIS User Guide, Rilis 2.6
17.3.6 About available algorithms
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 Antarmuka memproses batch
17.4.1 Pengantar
Semua algoritma (termasuk model) dapat dijalankan sebagai proses batch. Artinya, mereka dapat dijalankan menggunakan tidak hanya satu set masukan, namun beberapa dari mereka, melaksanakan algoritma sebanyak yang diperlukan. Hal ini berguna saat memproses data dalam jumlah besar, karena tidak perlu meluncurkan algoritma berkali-kali dari toolbox.
Untuk menjalankan algoritma sebagai proses batch, klik kanan pada namanya dalam kotak alat dan pilih opsi
Eksekusi sebagai proses batch di menu pop-up yang akan muncul.
Gambar 17.24: Klik Kanan Memproses Batch
17.4.2 Tabel parameter
Pelaksana proses batch mirip dengan melakukan eksekusi tunggal dari suatu algoritma. Nilai parameter harus didefinisikan, tetapi dalam kasus ini kita tidak perlu hanya nilai tunggal untuk masing-masing parameter, tapi satu set mereka sebagai gantinya, satu untuk setiap kali algoritma harus dieksekusi. Nilai akan diperkenalkan menggunakan tabel seperti yang ditunjukkan berikutnya.
Setiap baris dari tabel ini merupakan eksekusi tunggal algoritma, dan setiap sel berisi nilai salah satu parameter.
Hal ini mirip dengan dialog parameter yang Anda lihat ketika menjalankan sebuah algoritma dari toolbox, tapi dengan pengaturan yang berbeda.
Secara default, tabel berisi hanya dua baris. Anda dapat menambahkan atau menghapus baris menggunakan tombol pada bagian bawah jendela.
Setelah ukuran tabel telah ditetapkan, harus diisi dengan nilai-nilai yang diinginkan.
17.4.3 Mengarsipkan tabel parameter
Bagi kebanyakan parameter, menetapkan nilai sepele. Cukup ketik nilai atau pilih dari daftar pilihan yang tersedia, tergantung pada jenis parameter.
17.4. Antarmuka memproses batch 205
QGIS User Guide, Rilis 2.6
Gambar 17.25: Memproses Batch
Perbedaan utama yang ditemukan untuk parameter yang mewakili lapis atau tabel, dan untuk path berkas keluaran.
Mengenai masukan lapis dan tabel, ketika sebuah algoritma dijalankan sebagai bagian dari proses batch, obyek masukan data yang diambil langsung dari berkas, dan bukan dari aturan mereka yang sudah dibuka di QGIS.
Untuk alasan ini, algoritma dapat dijalankan sebagai proses batch, bahkan jika tidak ada obyek data sama sekali yang dibuka dan algoritma tidak dapat dijalankan dari toolbox.
Nama berkas untuk obyek masukan data diperkenalkan langsung dengan mengetik atau, lebih nyaman, mengklik tombol di sebelah kanan dari sel, yang menunjukkan dialog pemilih berkas. Beberapa berkas dapat dipilih sekaligus. Jika parameter masukan mewakili obyek data tunggal dan beberapa berkas yang dipilih, masing-masing dari mereka akan dimasukkan ke dalam baris yang terpisah, menambahkan yang baru jika diperlukan. Jika parameter mewakili banyak masukan, semua berkas yang dipilih akan ditambahkan ke satu sel, dipisahkan oleh titik koma ( ; ).
Obyek data keluaran akan selalu disimpan ke berkas dan, tidak seperti ketika menjalankan algoritma dari toolbox, menyimpan ke berkas sementara tidak diizinkan. Anda dapat mengetik nama secara langsung atau menggunakan dialog pemilih berkas yang muncul saat mengklik tombol yang menyertainya.
Setelah Anda memilih berkas, dialog baru ditampilkan untuk memungkinkan autocompletion dari sel-sel lain dalam kolom yang sama (parameter yang sama).
Gambar 17.26: Simpan Memproses Batch
Jika nilai default (‘Jangan AutoComplete’) yang dipilih, itu hanya akan menempatkan nama berkas yang dipilih dalam sel yang dipilih dari tabel parameter. Jika salah satu opsi lain yang dipilih, semua sel di bawah satu yang
206 Bab 17. QGIS kerangka pengolahan
QGIS User Guide, Rilis 2.6
dipilih otomatis akan diisi berdasarkan kriteria yang ditetapkan. Dengan cara ini, jauh lebih mudah untuk mengisi tabel, dan proses batch dapat didefinisikan dengan sedikit usaha.
Mengisi otomatis dapat dilakukan dengan hanya menambahkan angka korelatif untuk path berkas yang dipilih, atau dengan menambahkan nilai dari bidang lain pada baris yang sama. Hal ini sangat berguna untuk penamaan obyek data keluaran sesuai dengan yang masukan.
Gambar 17.27: Path Berkas Memproses Batch
17.4.4 Mengeksekusi proses batch
.
Untuk melaksanakan proses batch setelah Anda memperkenalkan semua nilai yang diperlukan, klik [OK] . Kemajuan tugas bets global akan ditampilkan dalam bar kemajuan di bagian bawah 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.
17.5. Using processing algorithms from the console 207
QGIS User Guide, Rilis 2.6
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
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)
208 Bab 17. QGIS kerangka pengolahan
QGIS User Guide, Rilis 2.6
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:
• 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
17.5. Using processing algorithms from the console 209
QGIS User Guide, Rilis 2.6
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.
• 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
.
210 Bab 17. QGIS kerangka pengolahan
QGIS User Guide, Rilis 2.6
• 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 .
• 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
17.5. Using processing algorithms from the console 211
QGIS User Guide, Rilis 2.6
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.
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 Manajer riwayat
17.6.1 Pemrosesan riwayat
Setiap kali Anda mengeksekusi sebuah algoritma, informasi tentang proses disimpan dalam manajer riwayat.
Seiring dengan parameter yang digunakan, tanggal dan waktu eksekusi juga disimpan.
Dengan cara ini, mudah untuk melacak dan mengendalikan semua pekerjaan yang telah dikembangkan dengan menggunakan kerangka pengolahan, dan mudah mereproduksi itu.
Manajer riwayat adalah satu set entri registri dikelompokkan berdasarkan tanggal eksekusi mereka, sehingga lebih mudah untuk menemukan informasi tentang algoritma yang dijalankan pada saat tertentu.
Informasi proses disimpan sebagai ekspresi baris-perintah, bahkan jika algoritma diluncurkan dari kotakalat. Hal ini juga berguna bagi mereka belajar bagaimana menggunakan antarmuka baris perintah, karena mereka dapat memanggil algoritma menggunakan kotak alat dan kemudian memeriksa manajer riwayat melihat bagaimana algoritma yang sama bisa dipanggil dari baris perintah.
Selain menjelajah entri dalam registri, Anda juga dapat jalankan kembali proses dengan hanya mengklik dua kali pada entri yang sesuai.
Seiring dengan rekaman algoritma eksekusi, kerangka pengolahan berkomunikasi dengan pengguna melalui kelompok lain dari registri, yaitu Eror , Peringatan dan Informasi . Dalam hal sesuatu yang tidak bekerja dengan baik, akan melihat Eror dapat membantu Anda untuk melihat apa yang terjadi. Jika Anda mendapatkan kontak
212 Bab 17. QGIS kerangka pengolahan
QGIS User Guide, Rilis 2.6
Gambar 17.28: Riwayat dengan pengembang melaporkan bug atau kesalahan, informasi dalam kelompok akan sangat berguna baginya atau untuk mencari tahu apa yang salah.
Algoritma pihak ketiga biasanya dilakukan dengan memanggil antarmuka baris perintah mereka, yang berkomunikasi dengan pengguna melalui konsol. Meskipun konsol yang tidak ditampilkan, dump penuh disimpan dalam grup Informasi setiap kali Anda menjalankan salah satu algoritma. Jika, misalnya, Anda mengalami masalah mengeksekusi algoritma SAGA, mencari entri bernama ‘keluaran konsol eksekusi SAGA’ untuk memeriksa semua pesan yang dihasilkan oleh SAGA dan coba mencari tahu di mana masalahnya.
Beberapa algoritma, bahkan jika mereka dapat menghasilkan hasil dengan masukan data yang diberikan, bisa menambahkan komentar atau informasi tambahan ke blok Peringatan jika mereka mendeteksi potensi masalah dengan data, dalam rangka untuk memperingatkan Anda. Pastikan Anda memeriksa pesan tersebut jika Anda mengalami hasil yang tidak diharapkan.
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)
17.7. Writing new Processing algorithms as python scripts 213
QGIS User Guide, Rilis 2.6
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, 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
214 Bab 17. QGIS kerangka pengolahan
QGIS User Guide, Rilis 2.6
• output html
• output file
• output number
• output string
• 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...)
17.8. Handing data produced by the algorithm 215
QGIS User Guide, Rilis 2.6
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 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.
216 Bab 17. QGIS kerangka pengolahan
QGIS User Guide, Rilis 2.6
.
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.
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.
17.14. Configuring external applications 217
QGIS User Guide, Rilis 2.6
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 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.
218 Bab 17. QGIS kerangka pengolahan
QGIS User Guide, Rilis 2.6
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
- 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.
17.14. Configuring external applications 219
QGIS User Guide, Rilis 2.6
##polyg=vector
##numpoints=number 10
##output=output vector
##sp=group pts=spsample(polyg,numpoints,type="random") output=SpatialPointsDataFrame(pts, as.data.frame(pts))
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:
220 Bab 17. QGIS kerangka pengolahan
QGIS User Guide, Rilis 2.6
##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).
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.
Catatan: 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.
17.14. Configuring external applications 221
QGIS User Guide, Rilis 2.6
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.
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
222 Bab 17. QGIS kerangka pengolahan
QGIS User Guide, Rilis 2.6
mkdir build cd build
Configure your build with the command
CXX=mpicxx cmake -DCMAKE_INSTALL_PREFIX=/usr/local ..
and then compile 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.
Gambar 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.
algorithm>
.
These are shown as
Processing algorithm: <name of the
• 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> .
17.15. The QGIS Commander 223
QGIS User Guide, Rilis 2.6
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.
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.
224 Bab 17. QGIS kerangka pengolahan
BAB
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
225
QGIS User Guide, Rilis 2.6
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>
226 Bab 18. Processing providers and algorithms
QGIS User Guide, Rilis 2.6
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
18.1. GDAL algorithm provider 227
QGIS User Guide, Rilis 2.6
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
228 Bab 18. Processing providers and algorithms
QGIS User Guide, Rilis 2.6
• 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)
18.1. GDAL algorithm provider 229
QGIS User Guide, Rilis 2.6
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
230 Bab 18. Processing providers and algorithms
QGIS User Guide, Rilis 2.6
• 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
18.1. GDAL algorithm provider 231
QGIS User Guide, Rilis 2.6
• 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>
232 Bab 18. Processing providers and algorithms
QGIS User Guide, Rilis 2.6
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
18.1. GDAL algorithm provider 233
QGIS User Guide, Rilis 2.6
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
234 Bab 18. Processing providers and algorithms
QGIS User Guide, Rilis 2.6
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>
18.1. GDAL algorithm provider 235
QGIS User Guide, Rilis 2.6
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>
236 Bab 18. Processing providers and algorithms
QGIS User Guide, Rilis 2.6
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
18.1. GDAL algorithm provider 237
QGIS User Guide, Rilis 2.6
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
238 Bab 18. Processing providers and algorithms
• 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>
QGIS User Guide, Rilis 2.6
18.1. GDAL algorithm provider 239
QGIS User Guide, Rilis 2.6
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)
240 Bab 18. Processing providers and algorithms
QGIS User Guide, Rilis 2.6
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
18.1. GDAL algorithm provider 241
QGIS User Guide, Rilis 2.6
• 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
242 Bab 18. Processing providers and algorithms
QGIS User Guide, Rilis 2.6
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
18.1. GDAL algorithm provider 243
QGIS User Guide, Rilis 2.6
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)
244 Bab 18. Processing providers and algorithms
QGIS User Guide, Rilis 2.6
.
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>
18.1. GDAL algorithm provider 245
QGIS User Guide, Rilis 2.6
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
246 Bab 18. Processing providers and algorithms
QGIS User Guide, Rilis 2.6
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
18.1. GDAL algorithm provider 247
QGIS User Guide, Rilis 2.6
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
248 Bab 18. Processing providers and algorithms
QGIS User Guide, Rilis 2.6
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
18.1. GDAL algorithm provider 249
QGIS User Guide, Rilis 2.6
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)
250 Bab 18. Processing providers and algorithms
QGIS User Guide, Rilis 2.6
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>
18.1. GDAL algorithm provider 251
QGIS User Guide, Rilis 2.6
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)
252 Bab 18. Processing providers and algorithms
QGIS User Guide, Rilis 2.6
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
18.1. GDAL algorithm provider 253
QGIS User Guide, Rilis 2.6
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
254 Bab 18. Processing providers and algorithms
QGIS User Guide, Rilis 2.6
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
18.1. GDAL algorithm provider 255
QGIS User Guide, Rilis 2.6
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)
256 Bab 18. Processing providers and algorithms
QGIS User Guide, Rilis 2.6
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>
18.1. GDAL algorithm provider 257
QGIS User Guide, Rilis 2.6
Console usage
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
258 Bab 18. Processing providers and algorithms
QGIS User Guide, Rilis 2.6
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
18.2. LAStools 259
QGIS User Guide, Rilis 2.6
• 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
260 Bab 18. Processing providers and algorithms
QGIS User Guide, Rilis 2.6
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)
18.2. LAStools 261
QGIS User Guide, Rilis 2.6
• 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)
262 Bab 18. Processing providers and algorithms
• 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)
18.2. LAStools
QGIS User Guide, Rilis 2.6
263
QGIS User Guide, Rilis 2.6
• 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:
264 Bab 18. Processing providers and algorithms
• 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
18.2. LAStools
QGIS User Guide, Rilis 2.6
265
QGIS User Guide, Rilis 2.6
• 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
266 Bab 18. Processing providers and algorithms
• 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
18.2. LAStools
QGIS User Guide, Rilis 2.6
267
QGIS User Guide, Rilis 2.6
• 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)
268 Bab 18. Processing providers and algorithms
• 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)
18.2. LAStools
QGIS User Guide, Rilis 2.6
269
QGIS User Guide, Rilis 2.6
• 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)
270 Bab 18. Processing providers and algorithms
• 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
18.2. LAStools
QGIS User Guide, Rilis 2.6
271
QGIS User Guide, Rilis 2.6
• 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
272 Bab 18. Processing providers and algorithms
• 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
18.2. LAStools
QGIS User Guide, Rilis 2.6
273
QGIS User Guide, Rilis 2.6
• 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
274 Bab 18. Processing providers and algorithms
QGIS User Guide, Rilis 2.6
• 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 — —
18.2. LAStools 275
QGIS User Guide, Rilis 2.6
• 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 description here>
Options:
• 0 — — parameter
• 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
276 Bab 18. Processing providers and algorithms
QGIS User Guide, Rilis 2.6
• 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>
18.2. LAStools 277
QGIS User Guide, Rilis 2.6
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
278 Bab 18. Processing providers and algorithms
QGIS User Guide, Rilis 2.6
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>
18.2. LAStools 279
QGIS User Guide, Rilis 2.6
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)
280 Bab 18. Processing providers and algorithms
QGIS User Guide, Rilis 2.6
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)
18.2. LAStools 281
QGIS User Guide, Rilis 2.6
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
282 Bab 18. Processing providers and algorithms
QGIS User Guide, Rilis 2.6
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
18.3. Modeler Tools 283
QGIS User Guide, Rilis 2.6
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>
284 Bab 18. Processing providers and algorithms
QGIS User Guide, Rilis 2.6
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.
Catatan: 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
18.4. OrfeoToolbox algorithm provider 285
QGIS User Guide, Rilis 2.6
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
286 Bab 18. Processing providers and algorithms
QGIS User Guide, Rilis 2.6
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>
18.4. OrfeoToolbox algorithm provider 287
QGIS User Guide, Rilis 2.6
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>
288 Bab 18. Processing providers and algorithms
QGIS User Guide, Rilis 2.6
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:
18.4. OrfeoToolbox algorithm provider 289
QGIS User Guide, Rilis 2.6
• 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>
290 Bab 18. Processing providers and algorithms
QGIS User Guide, Rilis 2.6
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
18.4. OrfeoToolbox algorithm provider 291
QGIS User Guide, Rilis 2.6
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>
292 Bab 18. Processing providers and algorithms
QGIS User Guide, Rilis 2.6
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>
18.4. OrfeoToolbox algorithm provider 293
QGIS User Guide, Rilis 2.6
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
294 Bab 18. Processing providers and algorithms
QGIS User Guide, Rilis 2.6
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
18.4. OrfeoToolbox algorithm provider 295
QGIS User Guide, Rilis 2.6
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>
296 Bab 18. Processing providers and algorithms
18.4. OrfeoToolbox algorithm provider
QGIS User Guide, Rilis 2.6
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
297
QGIS User Guide, Rilis 2.6
• 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
298 Bab 18. Processing providers and algorithms
QGIS User Guide, Rilis 2.6
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
18.4. OrfeoToolbox algorithm provider 299
QGIS User Guide, Rilis 2.6
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
300 Bab 18. Processing providers and algorithms
QGIS User Guide, Rilis 2.6
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:
18.4. OrfeoToolbox algorithm provider 301
QGIS User Guide, Rilis 2.6
• 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
302 Bab 18. Processing providers and algorithms
QGIS User Guide, Rilis 2.6
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
18.4. OrfeoToolbox algorithm provider 303
QGIS User Guide, Rilis 2.6
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)
304 Bab 18. Processing providers and algorithms
QGIS User Guide, Rilis 2.6
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
18.4. OrfeoToolbox algorithm provider 305
QGIS User Guide, Rilis 2.6
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
306 Bab 18. Processing providers and algorithms
QGIS User Guide, Rilis 2.6
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
18.4. OrfeoToolbox algorithm provider 307
QGIS User Guide, Rilis 2.6
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
308 Bab 18. Processing providers and algorithms
QGIS User Guide, Rilis 2.6
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>
18.4. OrfeoToolbox algorithm provider 309
QGIS User Guide, Rilis 2.6
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>
310 Bab 18. Processing providers and algorithms
QGIS User Guide, Rilis 2.6
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
18.4. OrfeoToolbox algorithm provider 311
QGIS User Guide, Rilis 2.6
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>
312 Bab 18. Processing providers and algorithms
QGIS User Guide, Rilis 2.6
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>
18.4. OrfeoToolbox algorithm provider 313
QGIS User Guide, Rilis 2.6
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>
314 Bab 18. Processing providers and algorithms
QGIS User Guide, Rilis 2.6
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
18.4. OrfeoToolbox algorithm provider 315
QGIS User Guide, Rilis 2.6
• 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>
316 Bab 18. Processing providers and algorithms
QGIS User Guide, Rilis 2.6
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>
18.4. OrfeoToolbox algorithm provider 317
QGIS User Guide, Rilis 2.6
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>
318 Bab 18. Processing providers and algorithms
QGIS User Guide, Rilis 2.6
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
18.4. OrfeoToolbox algorithm provider 319
QGIS User Guide, Rilis 2.6
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>
320 Bab 18. Processing providers and algorithms
QGIS User Guide, Rilis 2.6
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)
18.4. OrfeoToolbox algorithm provider 321
QGIS User Guide, Rilis 2.6
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>
322 Bab 18. Processing providers and algorithms
QGIS User Guide, Rilis 2.6
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>
18.4. OrfeoToolbox algorithm provider 323
QGIS User Guide, Rilis 2.6
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
324 Bab 18. Processing providers and algorithms
QGIS User Guide, Rilis 2.6
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:
18.4. OrfeoToolbox algorithm provider 325
QGIS User Guide, Rilis 2.6
• 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
326 Bab 18. Processing providers and algorithms
QGIS User Guide, Rilis 2.6
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>
18.4. OrfeoToolbox algorithm provider 327
QGIS User Guide, Rilis 2.6
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)
328 Bab 18. Processing providers and algorithms
QGIS User Guide, Rilis 2.6
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
18.4. OrfeoToolbox algorithm provider 329
QGIS User Guide, Rilis 2.6
• 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)
330 Bab 18. Processing providers and algorithms
QGIS User Guide, Rilis 2.6
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)
18.4. OrfeoToolbox algorithm provider 331
QGIS User Guide, Rilis 2.6
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
332 Bab 18. Processing providers and algorithms
QGIS User Guide, Rilis 2.6
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
18.4. OrfeoToolbox algorithm provider 333
QGIS User Guide, Rilis 2.6
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>
334 Bab 18. Processing providers and algorithms
QGIS User Guide, Rilis 2.6
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)
18.4. OrfeoToolbox algorithm provider 335
QGIS User Guide, Rilis 2.6
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>
336 Bab 18. Processing providers and algorithms
QGIS User Guide, Rilis 2.6
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
18.4. OrfeoToolbox algorithm provider 337
QGIS User Guide, Rilis 2.6
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
338 Bab 18. Processing providers and algorithms
QGIS User Guide, Rilis 2.6
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>
18.4. OrfeoToolbox algorithm provider 339
QGIS User Guide, Rilis 2.6
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
340 Bab 18. Processing providers and algorithms
QGIS User Guide, Rilis 2.6
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
18.4. OrfeoToolbox algorithm provider 341
QGIS User Guide, Rilis 2.6
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>
342 Bab 18. Processing providers and algorithms
QGIS User Guide, Rilis 2.6
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>
18.4. OrfeoToolbox algorithm provider 343
QGIS User Guide, Rilis 2.6
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>
344 Bab 18. Processing providers and algorithms
QGIS User Guide, Rilis 2.6
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
18.4. OrfeoToolbox algorithm provider 345
QGIS User Guide, Rilis 2.6
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
346 Bab 18. Processing providers and algorithms
QGIS User Guide, Rilis 2.6
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>
18.4. OrfeoToolbox algorithm provider 347
QGIS User Guide, Rilis 2.6
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
348 Bab 18. Processing providers and algorithms
QGIS User Guide, Rilis 2.6
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
18.4. OrfeoToolbox algorithm provider 349
QGIS User Guide, Rilis 2.6
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
350 Bab 18. Processing providers and algorithms
QGIS User Guide, Rilis 2.6
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
18.4. OrfeoToolbox algorithm provider 351
QGIS User Guide, Rilis 2.6
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
352 Bab 18. Processing providers and algorithms
QGIS User Guide, Rilis 2.6
• 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>
18.4. OrfeoToolbox algorithm provider 353
QGIS User Guide, Rilis 2.6
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
354 Bab 18. Processing providers and algorithms
QGIS User Guide, Rilis 2.6
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:
18.4. OrfeoToolbox algorithm provider 355
QGIS User Guide, Rilis 2.6
• 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
356 Bab 18. Processing providers and algorithms
QGIS User Guide, Rilis 2.6
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
18.4. OrfeoToolbox algorithm provider 357
QGIS User Guide, Rilis 2.6
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
358 Bab 18. Processing providers and algorithms
QGIS User Guide, Rilis 2.6
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>
18.4. OrfeoToolbox algorithm provider 359
QGIS User Guide, Rilis 2.6
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
360 Bab 18. Processing providers and algorithms
QGIS User Guide, Rilis 2.6
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
18.5. QGIS algorithm provider 361
QGIS User Guide, Rilis 2.6
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
362 Bab 18. Processing providers and algorithms
QGIS User Guide, Rilis 2.6
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
18.5. QGIS algorithm provider 363
QGIS User Guide, Rilis 2.6
• 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>
364 Bab 18. Processing providers and algorithms
QGIS User Guide, Rilis 2.6
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)
18.5. QGIS algorithm provider 365
QGIS User Guide, Rilis 2.6
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.
366 Bab 18. Processing providers and algorithms
QGIS User Guide, Rilis 2.6
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>
18.5. QGIS algorithm provider 367
QGIS User Guide, Rilis 2.6
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>
368 Bab 18. Processing providers and algorithms
QGIS User Guide, Rilis 2.6
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.
18.5. QGIS algorithm provider 369
QGIS User Guide, Rilis 2.6
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>
370 Bab 18. Processing providers and algorithms
QGIS User Guide, Rilis 2.6
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.
18.5. QGIS algorithm provider 371
QGIS User Guide, Rilis 2.6
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.
372 Bab 18. Processing providers and algorithms
QGIS User Guide, Rilis 2.6
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)
18.5. QGIS algorithm provider 373
QGIS User Guide, Rilis 2.6
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>
374 Bab 18. Processing providers and algorithms
QGIS User Guide, Rilis 2.6
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
18.5. QGIS algorithm provider 375
QGIS User Guide, Rilis 2.6
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)
376 Bab 18. Processing providers and algorithms
QGIS User Guide, Rilis 2.6
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
18.5. QGIS algorithm provider 377
QGIS User Guide, Rilis 2.6
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>
378 Bab 18. Processing providers and algorithms
QGIS User Guide, Rilis 2.6
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>
18.5. QGIS algorithm provider 379
QGIS User Guide, Rilis 2.6
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)
380 Bab 18. Processing providers and algorithms
QGIS User Guide, Rilis 2.6
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)
18.5. QGIS algorithm provider 381
QGIS User Guide, Rilis 2.6
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)
382 Bab 18. Processing providers and algorithms
QGIS User Guide, Rilis 2.6
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
18.5. QGIS algorithm provider 383
QGIS User Guide, Rilis 2.6
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>
384 Bab 18. Processing providers and algorithms
QGIS User Guide, Rilis 2.6
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>
18.5. QGIS algorithm provider 385
QGIS User Guide, Rilis 2.6
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)
386 Bab 18. Processing providers and algorithms
QGIS User Guide, Rilis 2.6
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)
18.5. QGIS algorithm provider 387
QGIS User Guide, Rilis 2.6
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>
388 Bab 18. Processing providers and algorithms
QGIS User Guide, Rilis 2.6
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)
18.5. QGIS algorithm provider 389
QGIS User Guide, Rilis 2.6
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>
390 Bab 18. Processing providers and algorithms
QGIS User Guide, Rilis 2.6
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)
18.5. QGIS algorithm provider 391
QGIS User Guide, Rilis 2.6
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)
392 Bab 18. Processing providers and algorithms
QGIS User Guide, Rilis 2.6
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)
18.5. QGIS algorithm provider 393
QGIS User Guide, Rilis 2.6
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)
394 Bab 18. Processing providers and algorithms
QGIS User Guide, Rilis 2.6
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)
18.5. QGIS algorithm provider 395
QGIS User Guide, Rilis 2.6
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)
396 Bab 18. Processing providers and algorithms
See also
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)
QGIS User Guide, Rilis 2.6
18.5. QGIS algorithm provider 397
QGIS User Guide, Rilis 2.6
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)
398 Bab 18. Processing providers and algorithms
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
18.5. QGIS algorithm provider
QGIS User Guide, Rilis 2.6
399
QGIS User Guide, Rilis 2.6
• 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)
400 Bab 18. Processing providers and algorithms
QGIS User Guide, Rilis 2.6
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
18.5. QGIS algorithm provider 401
QGIS User Guide, Rilis 2.6
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>
402 Bab 18. Processing providers and algorithms
QGIS User Guide, Rilis 2.6
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
18.5. QGIS algorithm provider 403
QGIS User Guide, Rilis 2.6
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)
404 Bab 18. Processing providers and algorithms
QGIS User Guide, Rilis 2.6
See also
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
18.5. QGIS algorithm provider 405
QGIS User Guide, Rilis 2.6
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
406 Bab 18. Processing providers and algorithms
QGIS User Guide, Rilis 2.6
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>
18.5. QGIS algorithm provider 407
QGIS User Guide, Rilis 2.6
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>
408 Bab 18. Processing providers and algorithms
QGIS User Guide, Rilis 2.6
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)
18.5. QGIS algorithm provider 409
QGIS User Guide, Rilis 2.6
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
410 Bab 18. Processing providers and algorithms
QGIS User Guide, Rilis 2.6
processing .
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)
18.5. QGIS algorithm provider 411
QGIS User Guide, Rilis 2.6
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)
412 Bab 18. Processing providers and algorithms
QGIS User Guide, Rilis 2.6
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
18.5. QGIS algorithm provider 413
QGIS User Guide, Rilis 2.6
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
Catatan: 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>
414 Bab 18. Processing providers and algorithms
QGIS User Guide, Rilis 2.6
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>
18.6. R algorithm provider 415
QGIS User Guide, Rilis 2.6
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>
416 Bab 18. Processing providers and algorithms
QGIS User Guide, Rilis 2.6
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>
18.6. R algorithm provider 417
QGIS User Guide, Rilis 2.6
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>
418 Bab 18. Processing providers and algorithms
QGIS User Guide, Rilis 2.6
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>
18.6. R algorithm provider 419
QGIS User Guide, Rilis 2.6
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>
420 Bab 18. Processing providers and algorithms
QGIS User Guide, Rilis 2.6
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
18.6. R algorithm provider 421
QGIS User Guide, Rilis 2.6
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
422 Bab 18. Processing providers and algorithms
QGIS User Guide, Rilis 2.6
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>
18.6. R algorithm provider 423
QGIS User Guide, Rilis 2.6
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.
Catatan: 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
424 Bab 18. Processing providers and algorithms
QGIS User Guide, Rilis 2.6
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
18.7. SAGA algorithm provider 425
QGIS User Guide, Rilis 2.6
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)
426 Bab 18. Processing providers and algorithms
QGIS User Guide, Rilis 2.6
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:
18.7. SAGA algorithm provider 427
QGIS User Guide, Rilis 2.6
• 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>
428 Bab 18. Processing providers and algorithms
QGIS User Guide, Rilis 2.6
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:
18.7. SAGA algorithm provider 429
QGIS User Guide, Rilis 2.6
• 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:
430 Bab 18. Processing providers and algorithms
QGIS User Guide, Rilis 2.6
• 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>
18.7. SAGA algorithm provider 431
QGIS User Guide, Rilis 2.6
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
432 Bab 18. Processing providers and algorithms
QGIS User Guide, Rilis 2.6
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:
18.7. SAGA algorithm provider 433
QGIS User Guide, Rilis 2.6
• 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>
434 Bab 18. Processing providers and algorithms
QGIS User Guide, Rilis 2.6
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:
18.7. SAGA algorithm provider 435
QGIS User Guide, Rilis 2.6
• 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>
436 Bab 18. Processing providers and algorithms
QGIS User Guide, Rilis 2.6
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)
18.7. SAGA algorithm provider 437
QGIS User Guide, Rilis 2.6
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>
438 Bab 18. Processing providers and algorithms
QGIS User Guide, Rilis 2.6
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>
18.7. SAGA algorithm provider 439
QGIS User Guide, Rilis 2.6
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>
440 Bab 18. Processing providers and algorithms
QGIS User Guide, Rilis 2.6
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
18.7. SAGA algorithm provider 441
QGIS User Guide, Rilis 2.6
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>
442 Bab 18. Processing providers and algorithms
QGIS User Guide, Rilis 2.6
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)
18.7. SAGA algorithm provider 443
QGIS User Guide, Rilis 2.6
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>
444 Bab 18. Processing providers and algorithms
QGIS User Guide, Rilis 2.6
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)
18.7. SAGA algorithm provider 445
QGIS User Guide, Rilis 2.6
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)
446 Bab 18. Processing providers and algorithms
QGIS User Guide, Rilis 2.6
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)
18.7. SAGA algorithm provider 447
QGIS User Guide, Rilis 2.6
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>
448 Bab 18. Processing providers and algorithms
QGIS User Guide, Rilis 2.6
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>
18.7. SAGA algorithm provider 449
QGIS User Guide, Rilis 2.6
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)
450 Bab 18. Processing providers and algorithms
QGIS User Guide, Rilis 2.6
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>
18.7. SAGA algorithm provider 451
QGIS User Guide, Rilis 2.6
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
452 Bab 18. Processing providers and algorithms
QGIS User Guide, Rilis 2.6
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
18.7. SAGA algorithm provider 453
QGIS User Guide, Rilis 2.6
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
454 Bab 18. Processing providers and algorithms
QGIS User Guide, Rilis 2.6
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>
18.7. SAGA algorithm provider 455
QGIS User Guide, Rilis 2.6
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
456 Bab 18. Processing providers and algorithms
QGIS User Guide, Rilis 2.6
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
18.7. SAGA algorithm provider 457
QGIS User Guide, Rilis 2.6
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
458 Bab 18. Processing providers and algorithms
QGIS User Guide, Rilis 2.6
• 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.
18.7. SAGA algorithm provider 459
QGIS User Guide, Rilis 2.6
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>
460 Bab 18. Processing providers and algorithms
QGIS User Guide, Rilis 2.6
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)
18.7. SAGA algorithm provider 461
QGIS User Guide, Rilis 2.6
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
462 Bab 18. Processing providers and algorithms
QGIS User Guide, Rilis 2.6
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)
18.7. SAGA algorithm provider 463
QGIS User Guide, Rilis 2.6
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)
464 Bab 18. Processing providers and algorithms
QGIS User Guide, Rilis 2.6
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>
18.7. SAGA algorithm provider 465
QGIS User Guide, Rilis 2.6
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>
466 Bab 18. Processing providers and algorithms
QGIS User Guide, Rilis 2.6
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
18.7. SAGA algorithm provider 467
QGIS User Guide, Rilis 2.6
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)
468 Bab 18. Processing providers and algorithms
QGIS User Guide, Rilis 2.6
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
18.7. SAGA algorithm provider 469
QGIS User Guide, Rilis 2.6
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
470 Bab 18. Processing providers and algorithms
QGIS User Guide, Rilis 2.6
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>
18.7. SAGA algorithm provider 471
QGIS User Guide, Rilis 2.6
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>
472 Bab 18. Processing providers and algorithms
QGIS User Guide, Rilis 2.6
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
18.7. SAGA algorithm provider 473
QGIS User Guide, Rilis 2.6
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
474 Bab 18. Processing providers and algorithms
QGIS User Guide, Rilis 2.6
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
18.7. SAGA algorithm provider 475
QGIS User Guide, Rilis 2.6
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>
476 Bab 18. Processing providers and algorithms
QGIS User Guide, Rilis 2.6
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>
18.7. SAGA algorithm provider 477
QGIS User Guide, Rilis 2.6
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)
478 Bab 18. Processing providers and algorithms
QGIS User Guide, Rilis 2.6
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>
18.7. SAGA algorithm provider 479
QGIS User Guide, Rilis 2.6
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
480 Bab 18. Processing providers and algorithms
QGIS User Guide, Rilis 2.6
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:
18.7. SAGA algorithm provider 481
QGIS User Guide, Rilis 2.6
• 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
482 Bab 18. Processing providers and algorithms
QGIS User Guide, Rilis 2.6
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)
18.7. SAGA algorithm provider 483
QGIS User Guide, Rilis 2.6
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>
484 Bab 18. Processing providers and algorithms
QGIS User Guide, Rilis 2.6
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)
18.7. SAGA algorithm provider 485
QGIS User Guide, Rilis 2.6
.
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
486 Bab 18. Processing providers and algorithms
QGIS User Guide, Rilis 2.6
• 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>
18.7. SAGA algorithm provider 487
QGIS User Guide, Rilis 2.6
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>
488 Bab 18. Processing providers and algorithms
QGIS User Guide, Rilis 2.6
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)
18.7. SAGA algorithm provider 489
QGIS User Guide, Rilis 2.6
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
490 Bab 18. Processing providers and algorithms
QGIS User Guide, Rilis 2.6
processing .
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>
18.7. SAGA algorithm provider 491
QGIS User Guide, Rilis 2.6
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
492 Bab 18. Processing providers and algorithms
QGIS User Guide, Rilis 2.6
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)
18.7. SAGA algorithm provider 493
QGIS User Guide, Rilis 2.6
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>
494 Bab 18. Processing providers and algorithms
QGIS User Guide, Rilis 2.6
Console usage
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>
18.7. SAGA algorithm provider 495
QGIS User Guide, Rilis 2.6
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
496 Bab 18. Processing providers and algorithms
QGIS User Guide, Rilis 2.6
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>
18.7. SAGA algorithm provider 497
QGIS User Guide, Rilis 2.6
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>
498 Bab 18. Processing providers and algorithms
QGIS User Guide, Rilis 2.6
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>
18.7. SAGA algorithm provider 499
QGIS User Guide, Rilis 2.6
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>
500 Bab 18. Processing providers and algorithms
18.7. SAGA algorithm provider
QGIS User Guide, Rilis 2.6
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
501
QGIS User Guide, Rilis 2.6
• 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
502 Bab 18. Processing providers and algorithms
QGIS User Guide, Rilis 2.6
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:
18.7. SAGA algorithm provider 503
QGIS User Guide, Rilis 2.6
• 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>
504 Bab 18. Processing providers and algorithms
QGIS User Guide, Rilis 2.6
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
18.7. SAGA algorithm provider 505
QGIS User Guide, Rilis 2.6
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
506 Bab 18. Processing providers and algorithms
QGIS User Guide, Rilis 2.6
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>
18.7. SAGA algorithm provider 507
QGIS User Guide, Rilis 2.6
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>
508 Bab 18. Processing providers and algorithms
QGIS User Guide, Rilis 2.6
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>
18.7. SAGA algorithm provider 509
QGIS User Guide, Rilis 2.6
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
510 Bab 18. Processing providers and algorithms
QGIS User Guide, Rilis 2.6
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>
18.7. SAGA algorithm provider 511
QGIS User Guide, Rilis 2.6
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
512 Bab 18. Processing providers and algorithms
QGIS User Guide, Rilis 2.6
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)
18.7. SAGA algorithm provider 513
QGIS User Guide, Rilis 2.6
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
514 Bab 18. Processing providers and algorithms
QGIS User Guide, Rilis 2.6
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
18.7. SAGA algorithm provider 515
QGIS User Guide, Rilis 2.6
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
516 Bab 18. Processing providers and algorithms
QGIS User Guide, Rilis 2.6
• 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
18.7. SAGA algorithm provider 517
QGIS User Guide, Rilis 2.6
• 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
518 Bab 18. Processing providers and algorithms
QGIS User Guide, Rilis 2.6
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
18.7. SAGA algorithm provider 519
QGIS User Guide, Rilis 2.6
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>
520 Bab 18. Processing providers and algorithms
QGIS User Guide, Rilis 2.6
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>
18.7. SAGA algorithm provider 521
QGIS User Guide, Rilis 2.6
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>
522 Bab 18. Processing providers and algorithms
QGIS User Guide, Rilis 2.6
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
18.7. SAGA algorithm provider 523
QGIS User Guide, Rilis 2.6
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
524 Bab 18. Processing providers and algorithms
QGIS User Guide, Rilis 2.6
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>
18.7. SAGA algorithm provider 525
QGIS User Guide, Rilis 2.6
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)
526 Bab 18. Processing providers and algorithms
QGIS User Guide, Rilis 2.6
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.
18.7. SAGA algorithm provider 527
QGIS User Guide, Rilis 2.6
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>
528 Bab 18. Processing providers and algorithms
QGIS User Guide, Rilis 2.6
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)
18.7. SAGA algorithm provider 529
QGIS User Guide, Rilis 2.6
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.
530 Bab 18. Processing providers and algorithms
QGIS User Guide, Rilis 2.6
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.
18.7. SAGA algorithm provider 531
QGIS User Guide, Rilis 2.6
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