Python bindings for QGIS.

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881 views

Load and display a layer from SQL Server using PyQGIS

I'm having a go at using pyqgis from within the QGIS python console to load a layer from SQL Server and display it. I feel like I'm part way there but I'm having a real issue getting the layer to ...
5
votes
1answer
756 views

Using the Processing Framework in QGIS 2.0

I am writing a plugin for QGIS 2.0, and I want to use the processing framework to call some functions. When I open the pyhton console inside QGIS, I am able to call it like this: >> import ...
5
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1answer
611 views

QGis Zonal Statistics Plugin NoData included in Calculations

I have been trying to use the QGIS zonal statistics plugin. My raster has a nodata value of -99999 and all other values are positive. After computing the mean zonal statistics there are a number of ...
5
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1answer
1k views

How to get pixel size/cell size of raster layer?

After much searching, I've still not been able to figure out how to perform what seems like a simple function: I'd like to get the pixel size/cell size of a raster layer using PyQgis. Is there any ...
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0answers
273 views

Performing buffering and intersection with script in PyQGIS

I wrote a script that performs the intersection of two layers: The first Layer -> layer1, represents the rivers The second Layer -> layer2, represents a set of circular dots distributed in a ...
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0answers
785 views

PyQGIS CRS on the fly reprojetion [closed]

As a first step of a pyqgis plugin I'm trying to import several shape files at once. To get them aligned, using the GUI, I'd enable on the fly reprojections and set the project crs to WGS84. I'd then ...
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2answers
1k views

Get a pixel value

How can i do this operation: I want to get a pixel value fro the satellite image (Landat, GeoTIFF, 7 bands) using qgis-python. What operators should i use? (for example in qgis's Python Console) ...
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5answers
212 views

Is there any simple integration for counting points in polygon using python qgis?

Is there any simple integration for calculating count of points in polygon using QGIS-Python integration? In other words, are there any pre-defined functions for points in polygon of QGIS using ...
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2answers
588 views

Using Python and open source modules, how can I perform Raster Calculator functions?

I would like to perform mathematical functions similar to those you would use Raster Calculator for in ArcMap, however I'd like to do it in Python without using the Arcpy module. I have the osgeo ...
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2answers
2k views

Programmatically load composer from template and generate atlas using pyQgis

I Am trying to build a plugin to load a print composer from file, generate an atlas and export to image. So far I have been successful in loading the template and exporting it to image. I have been ...
4
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2answers
4k views

How to perform SQL queries and get results from QGIS python console?

I'm writing a python script using QGIS API. I have to get results from postgres database table. The table has geometry field and other non-geometry fields. I want to perform SQL queries on ...
4
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1answer
3k views

pyqgis: How to get features of selected geometries

I wonder if anybody could provide an example how to get the attributes of selected Features? I tried the folowing Code in the python Console - but I'm stuck at the point where I'd like to get the ...
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3answers
104 views

Change QGIS background colour using python

I would like to change the background colour of a QGIS project using python. I can change the colour using the GUI via the Project Properties dialog: However, I cannot find the equivalent setting ...
4
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1answer
203 views

Calculate line lengths with Python in QGIS

I found this article which describes the "QGIS GUI way" for calculating the line lengths. http://www.qgistutorials.com/en/docs/calculating_line_lengths.html How can I calculate the length of one line ...
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2answers
2k views

Problem loading vector layer (pyQGIS)

I've installed the qgis on ubuntu 12.04 following the instructions on http://hub.qgis.org/projects/quantum-gis/wiki/Download. I am trying to test the Python API and try to do the follwoing from ...
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2answers
468 views

Adding a vector layer at QGIS start

I have added a shape file in QGIS using Python plugin. I want to add this shape file when QGIS is loading so i have to add code in the initgui() method. I have used following code in the initgui() ...
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1answer
486 views

How to begin with tool development for GRASS gis or QGIS GRASS

I wanted to begin with customized tool development in Grass GIS or QGIS grass. How should i begin in to develop the tool. I search a lot in google search engine for begin with tool development in ...
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1answer
1k views

Get extents of vector shape features in python

i am just wondering if it is possible to iterate through vector features and return the extent per feature without clipping the vector shape? The code looks like this and comes from the ...
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2answers
31 views

Retrieve available PostGIS connections in PyQGIS

Can I retrieve the available connections to PostGIS databases in PyQGIS? I would like to provide a list of available db-connections, and subsequently a list of tables within the ui of my plugin. I ...
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2answers
135 views

How to build QgsExpressions in python?

How can I build a feature request expression using variable inside expression? For example values = [1, 2, 3] for j in range( y ): it = vl.getFeatures( QgsFeatureRequest().setFilterExpression ( ...
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2answers
120 views

How to activate a layer by its name in PyQGIS?

I'm writing a script that requires the attributes of different layers to work, and I would like to know how to call a layer that is not the currently active one and get its features. For example, I ...
4
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1answer
99 views

Select a column like Primary Key in a View from PostGIS using PyQGIS in QGIS

Postgresql doesn't support Primary Key in views. When I load a postGIS view in QGIS "manually", I can choose the column that will be the Primary Key, but I would like to know if I can select a column ...
4
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2answers
935 views

How can I access `processing` with Python?

I want to access the explode lines function in Python outside of QGIS from a standalone script. What module do I have to load in order to use it? How can I access processing? from qgis.core import * ...
4
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1answer
633 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 ...
4
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4answers
588 views

How to display a “Save As” dialog for raster files?

I'm writing a QGIS plugin in python. I need to show a "Save as" dialog window in order to allow the user to select the path of the output raster file. Do I need to create a QFileDialog and manually ...
4
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1answer
54 views

Problem Editing a Vector Layer QGIS

I have a vector layer which I need to load and edit (add several attribute columns). I am doing this without opening QGIS, so within a python script. I have the following piece of code for the layer ...
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1answer
59 views

How to get the list of QgsPoint from a polygon Layer in pyqgis

I have a little question about how to manage the points in a layer. from qgis.core import * def run_script(iface): layer = QgsVectorLayer(layerType.Polygon+'?'+crs.psg_4326, ...
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1answer
234 views

How to show Python console at QGIS program start

I wonder if there is a way to open the Python console of QGIS 2.6 directly at program launch. There is a possibility to set a shortcut for the Python console, but I can't find such an option for the ...
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1answer
327 views

getting a plugin path using Python in QGIS

How to get a plugin path using Python? I tried QgsApplication.pluginPath() I got u'/Applications/QGIS.app/Contents/MacOS/../PlugIns/qgis' But I actually store the plugin in ...
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2answers
673 views

Programatically use Openlayers plugin layer in Print Composer

I created some PyQGIS functions to set up a print composer, modify the layout (adding maps, legend, title...) and print the result as an image file. This works fine with one or several vector layers - ...
4
votes
1answer
454 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() ...
4
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1answer
324 views

How to programmatically detect a canvas refresh or pan/zoom in QGIS

For my python plugin I would like to remove a VertexMarker when the user pans/zooms there map. Which is the best way to detect a canvas refresh or pan/zoom carried out by the user? Can you suggest ...
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1answer
783 views

Is it possible to programmatically add calculated fields?

In the Memory provider described in PyQGIS Cookbook or in question How to create a new empty vector layer programmatically? I can see how to create a vector layer programmatically using standard ...
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2answers
1k views

How can I add OpenLayers layer from the python console?

I am new to the python console. How can I add a layer from the OpenLayers plugin from the python console? Thank you
4
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1answer
59 views

Troubles Updating Values of Selected Features with PyQGIS

I'm trying to modify the values of some selected features. I have written this small script, but nothing happens when I run it. Is there something that I've missed? Here is my code. lyr = ...
4
votes
1answer
58 views

Adding a PyQGIS Plugin to the Database Menu

I am developing a plugin which I would like to add to the Database menu instead of the default Plugins menu. According to the PyQGIS Developer Cookbook all I have to do is add category=Database to ...
4
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2answers
2k views

PyQgis overwrite shape file and adding layer to Qgis

I am creating a shapefile in python by: driver = ogr.GetDriverByName('ESRI Shapefile') datasource = driver.CreateDataSource('c:/temp/toke2.shp') layer = ...
4
votes
1answer
39 views

How to toggle group visibility in QGIS using Python?

I've tried this, but it doesn't work out. root = QgsProject.instance().layerTreeRoot() group1 = root.insertGroup(0, "PGB") legend = i.legendInterface() legend.isGroupVisible(group1) ...
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2answers
54 views

performance problem with PyQGIS: manipulating attributes

I have selected a vector layer with attributes slope and area. I want to combine all the features with slope 0 to 5, 5 to 10, ... , 85 to 90. The original features are to be discarded, and new ...
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1answer
33 views

Merging Features

I want to merge features of a vector layer into one single feature using the python console. Somewhere I found the following solution. However it does not seem to work for me. When I execute the ...
4
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1answer
65 views

Rename field QgsField is not valid

In pyQGIS i tried this code (contains also debug prints): def joinLayers(inputlayer, layer, index_field, name = "JOINED", dataProvider = "ESRI Shapefile"): a = [] b = [] outpath = ...
4
votes
3answers
112 views

Quickly make server side spatial filters for WFS layers based on other layer's selected geometries in QGIS

In QGIS 2.12.1, I have a WFS layer which is huge so I don't want my users to load it entirely but only parts of it based on intersections with geometries. Today, I'm using the query builder and ...
4
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1answer
99 views

Converting Python script for QGIS?

I am still a novice in python, but I have the long term goal to create a plugin one day. The first step to this plugin is a test with QGIS python scripts to convert an Access mdb into sqlite db and ...
4
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1answer
159 views

QGIS Export Shapefile

i am trying to export selected feature using pyqgis. till now i have tried these codes. after using this i can select feature but dont know how to export selected feature to new shapefile. canvas= ...
4
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1answer
117 views

How to add an attribute with QGIS 2.8.1 Python console?

i would like to add an attribute with the python console: from PyQt4.QtCore import * from PyQt4.QtGui import * layer = iface.addVectorLayer("C:/donnees_SIG/05.shp","nou","ogr") layer = ...
4
votes
1answer
617 views

Removing a vector layer from QGIS [duplicate]

Considering my program is generating a shapefile that has to be added to the "Layers" tab in QGIS interface. However, once the utility of the layer is completed, I need to remove the layer in the ...
4
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1answer
228 views

Making QGIS buttons and my Plugin button mutually exclusive

I've added a toolbar to the QGIS main window and I've added some checkable buttons to the toolbar. How can I make my checkable buttons untoggle QGIS default toolbars' checkable buttons? That is, ...
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1answer
1k 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 ...
4
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1answer
518 views

Programmatically change layer position in the table of contents (QGIS)

I am trying move/position a layer to the bottom of the TOC by using addTopLevelItem on all other layers. I unsure how to reference the layers as QTreeWidgetItem's. def bg_bottom_level_item(self): ...
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2answers
2k views

Setting the extent for a QGIS map using python

I am writing a stand-alone application in Python/QGIS that simply creates maps. I want to load vector/raster layers, set symbology, set extent At the moment, that is all! Currently I am just using ...