Python bindings for QGIS.

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How to open, modify and save a QGIS project with PYQGIS

I need to create a stand-alone script for opening a QGIS template project, modify a layer data source, export the Composition and finally save the modified .qgs project into a new file. So far I have ...
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1answer
141 views

How to programmatically export a composition as image?

QGIS Print Composer has tool "Save As Image" and I found appropriate function in QGIS source code exportCompositionAsImage. Is it possible to get access to existing Print Composer from Python console ...
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42 views

Couldn't load PyQGIS in QGIS 2.2 on Ubuntu 14.04 [duplicate]

This issue appears to be occurring with some frequency to folks in some shape or form. I upgraded from ubuntu 12.04 to 14.04, with loss of python functionality. My QGIS version is 2.2 from the ...
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1answer
40 views

QGIS API documentation in French?

I am looking for a document which explains what the API of QGIS is, with examples of this API but in French.
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49 views

Is it possible to customize openFeatureForm of pyqgis?

I am a beginner in PyQgis. I am trying create a plugin, which will be used to AddFeatue,Delete Feature, and Edit the Feature. It is more customized than which is provided by Qgis (2.2). I am capturing ...
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2answers
139 views

How to get features based on their attributes using Python - special characters?

I want to get features based on their attributes and it works fine when I use this Python script: canvas = iface.mapCanvas() curLayer = canvas.currentLayer() it = ...
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1answer
342 views

How to find the id of the last added feature using pyQGIS?

Is it possible to programmatically (in python) access the attribute info of the last added feature in QGIS 2.0 before edits are saved? I'm failing to find a way to get the ID and subsequently other ...
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2answers
584 views

How to change the value of an attribute using QgsFeature in PyQGIS?

I would like to update one attribute of a feature. However, I don't know to update it using the feature object. I have to use data provider to update it. layers = ...
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1answer
59 views

PyQgis api returns wrong layer CRS

I have shape vector layer in ESPG:3859 CRS. I try to get layer crs layer.crs.geographicCRSAuthId() but method always returns EPSG:4326 no matters which CRS I chose in layer properties. .qpj file ...
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50 views

What is the QGIS 2.2 print layout map extent CRS?

I have project in ESPG:4326 with 2 layers (both in 4326), and map print layout. I've chosen current extent for layout map. Map is centered and prints as I expect. Next, I access this object via ...
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175 views

Using qgis modules in standalone application with PySide?

I want to make small standalone application using PySide and QGIS python modules to display satellite images and do standard GIS operations, like creating new shape file and placing polygons or points ...
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1answer
176 views

How to add an interpolation raster from the python console in QGIS?

I'm trying to add an interpolation layer based on an existing vector layer by using the Python Console (initially in the menu Raster/Interpolation), but can't find anything related in the ...
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245 views

How to make a routable graph from a Point and a Line shapefile, using Networkx?

I have one shapefile which consists of all the streets in the study area, and another shapefile which has points representing origins and destinations. I would like to know if it's possible to find ...
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1answer
366 views

How to make a Python script that does a task in QGIS?

When I run this code in QGIS Python console it works fine, but I want want to run it from an external Python script. What I want the script to do is: 1- Open QGIS 2- Run this code 3- Close QGIS from ...
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164 views

PyQGIS: Programmatically Adding Point Features via QgsMapToolEmitPoint

I've created a map tool for QGIS 2.0 Python plugin that emits a point with the click of the mouse. I'm trying to create an edit tool, adding a point feature at the emitted point while selecting ...
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85 views

How to integrate pascal code into a QGIS model or plugin?

I have a console program that is written in pascal (lazarus) that reads in some raster files and parameter values as input. The code use dynamic 2D arrays to represent the rasters. I would like to ...
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45 views

How to select a specific area (in a polygon form) determined by some value range in a raster band?

For example, I want create a vector layer with polygons that represents all areas where the elevation is between 500 and 600. Someone has any idea to help me? I'm using PyQgis 2.2.
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90 views

PyQGIS: How to send signal to call unsetMapTool()

I've created a map tool to add some functionality to adding point features in QGIS 2.0. I'd like to unset this map tool if editing has manually been terminated by user. I've attempted as shown below, ...
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196 views

QGIS GUI Python Editor Code Running Exception

import sys from PyQt4 import QtGui class MessageBox(QtGui.QWidget): def __init__(self, parent=None): QtGui.QWidget.__init__(self, parent) self.setGeometry(300, 300, 250, 150) ...
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439 views

Iterating over selected features in QGIS Processing

I used to be able to iterate over selected features using the following script in v2.0. import processing features = processing.getfeatures(layer) for feature in features: #Do whatever you need ...
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1answer
141 views

Programmatically set layer properties Python Init function

Is it possible to set the layer properties Python Init function field programmatically? I've been looking through the qgis 2.2 api but can't seem to find anything on it. Hint, suggestions and ...
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1answer
126 views

Developing QGIS plugin on Mac - GDAL

I'm developing a plugin for QGIS called DEMtools. It runs fine on my linux machine, but is causing me headaches when run on Mac OS X Mavericks (surprise, surprise). I keep getting segmentation faults ...
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1answer
199 views

Import error when utilizing QGIS's Python Init function

Based on the answer to Referencing Qt UIs external to plugin with python. I'm trying to utilize the "Layer Properties / Fields / Python Init function" to execute a file (test_file.py) that is located ...
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1answer
103 views

Referencing Qt UIs external to plugin with python

I'm developing a plugin that sets up a working environment for a user: loading layers (from db), applying styles and several custom designed (Qt) UI files etc. Primary user interaction is in the ...
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1answer
65 views

Errors uploading plugin to QGIS python plugin repository

I'm trying to upload my first plugin to: http://plugins.qgis.org/plugins/add/ I keep getting the following error: There were errors reading plugin package (please check also your plugin's ...
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51 views

Running algorithm from Processing takes much much longer time than doing it from Qgis GUI

I have a road layer with 32000 features, and I want to find all the intersections. when I use processing->SAGA -> convert polygon/line vertices to points, it is all done in less than 5 seconds. ...
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269 views

How to get the map canvas CRS in EPSG code?

This is probably a simple request but I cannot find a way around it: how can I read from python the map canvas CRS? I know how to set it up: canvas = self.iface.mapCanvas() ...
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1answer
103 views

How to open most recent directory using PyQGIS?

For example, when I add a vector layer, next time that I want to add another layer it opens up where I chose my last layer from. How would one implement this in Python and/or PyQgis? I'm writing a ...
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94 views

Determine Transect line to cover area

I'm near certain this is a solved problem, but I haven't been able to find a solution from searches so here's my situation (probably I'm searching the wrong thing)... I need to compute the ...
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36 views

Using QgsSpatialIndex for spatial join

I've written a bit of code to do a simple spatial join in QGIS 2 and 2.2 (points that lie within a buffer to take attribute of the buffer). However, I'd like to employ a QgsSpatialIndex in order to ...
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466 views

QVariant is not defined when using addAttributes [closed]

When I try to add a field programmatically with the following code: import os.path from PyQt4 import QtGui, QtCore legend = qgis.utils.iface.legendInterface() allLayers = legend.layers() for i in ...
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23 views

Is it possible to override default QGIS error messages?

From my QGIS plugin I would like to override/replace one of the the default QGIS error message ("The layer layer_url is not a valid layer and can not be added to the map") with my own message. I have ...
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1answer
200 views

Accessing CRS info with pyqgis in a standalone application

I'm currently having trouble accessing and defining CRS information in a standalone application. I've read the API documentation and have tried it in the python console in QGIS 2.2.0. The python ...
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1answer
870 views

“Couldn't load PyQGIS” Error running QGIS on Ubuntu 14.04

I have installed QGis on Ubuntu 14.04 from the QGis stable repository; it went fine with no errors reported. But when I launch QGis I get this huge window with the following message: Couldn't load ...
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0answers
75 views

QGIS python plugin: PyQGIS for spatial join

For a QGIS 2.0 and 2.2 Python plugin, I am trying to update one layer's field attribute with another layer's field attribute based on geometry function QgsGeometry.within(). My first layer is a point ...
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1answer
408 views

Converting models from QGIS to Python scripts?

I want to automate some tools for QGIS 2.0.2 using Python. Previously I have used ArcMap for automating tools and now i want to use QGIS. In ArcMap I used the ModelBuilder, and more specifically the ...
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129 views

PyQGIS: How to color raster layer with existing colorBrewerMap

With pyqgis I have added multiple new raster layers to the legendinterface(). Because i like the ColorBrewer style i want to color some of them with the "Spectral" gradient. How can I do this in ...
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2answers
219 views

PyQGIS: How to send signal if layer is currently in edit mode

I'm looking for a way to send a signal if a layer is in editing mode. I tried editingStarted(), but it wasn't working. I'd like to do something along the lines of the what I have below, but can't find ...
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1answer
77 views

Finding Code in QGIS Select Features Toolset

Can anyone tell me in what directory the pre-installed Python scripts for the QGIS selection tools (i.e., Select by Point, Select by Polygon) are found? I am using on a Windows 7 installation of QGIS ...
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1answer
159 views

How to implement 1:n joins with string attribute concatenation?

I have a question concerning pyQGIS. I'm a QGIS long-time (self-learned) user, but just a pyQGIS newbie. I want to implement 1:n spatial join with attribute concatenation in the table. I have a vector ...
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1answer
158 views

order layer in QGIS with pyqgis

I´m new in pyqgis. I´m looking for a code to move one layer in TOC to a specific position. Is it possible? Thanks a lot!
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1answer
321 views

How to use Threads in PyQgis, mainly to keep UI active?

I'm trying to develop a plugin, which does heavy computations and as a result, user interface becomes inactive. I know that I should use threads to keep the UI alive (specifically, I have a progress ...
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1answer
314 views

How can i use python QGis network analysis library to calculate short path based on speed and distance?

I want to calculate and show short path from starting point to an end point in a qgis python plugin. in my research i stopped by an article about QGis network analysis library; ...
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1answer
104 views

How to batch interpolate many shp´s to DEM

Here´s the problem: I have about 40 shapefiles of contourlines (type line) and I need to interpolate them to create DEM's (tiff, or better some grid format). To do so, some batch scripting would be ...
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0answers
63 views

How to include external libraries with my QGIS plugin?

I'm developing a plugin which makes use of "networkx" library extensively. However, networkx is not part of Python libraries pre-installed in QGIS. Is there a way to include this library with my ...
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118 views

Programmatically selecting features by polygon

Expanding upon this post how could you use QGis to programmatically draw a selection polygon and select features within the polygon? I have been using QgsMapToolEmitPoint(self.canvas), to find and ...
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2answers
506 views

How to calculate distance in meter between QgsPoint objects in PyQgis?

I tried to calculate distance between QgsPoint objects in qgis, i used QgsPoint StartPoint.sqrDist(EndPoint). but i don't find an expected result, i also tried import math ...
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1answer
324 views

How to populate a combobox with layers in TOC?

I am developing a plugin, and I want user to select one of the loaded layers from a combobox. I've already coded this much: self.dlg.show() layerlist = [] self.dlg.ui.layerCombo.clear() # ...
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1answer
96 views

How can I use pyqgis to automate a series of field calculations?

I've got a shapefile with about 30 fields that I'll need to update from time to time by importing a CSV with new data, joining it to the shapefile, and using the field calculator to carry the new ...
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107 views

How can I get the set of points (cloud) that are a given distance in SpatiaLite?

I have a set of points and need to get the groups of points that are within a distance x. Ie, determining the point clouds that are up to the distance x from each other. Any help would be ...