Python bindings for QGIS.

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How to find all intersections and count lines arriving at each intersection?

I'm having a hard time getting off the ground with this, and am trying to move away from ArcGIS / arcpy. I have a shapefile with a network of polylines. I want to find/count all 2-way intersections, ...
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2answers
103 views

Start QGIS with virtualenv Python

is there any means of telling QGIS to use a different Python installation than the default, system-wide one? E.g. use some virtualenv Python /myvirtualenv/bin/python instead of /usr/bin/python? ...
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2k views

How can I Setup Python to recognize QGIS

I want to use QGIS and work with Python out of the console, but I'm having troubles letting the system recognize the paths of some DLLs. Since I couldn't find a good answer on the web, I wonder if I ...
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210 views

How to open QGIS attribute table in form view using Python?

I've got a plugin where I load some layers. After the last layer loaded, I show the attribute table. However, I would like to select the form view and not the table view (see image). How can I do ...
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659 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 ...
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506 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 ...
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997 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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734 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 ...
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626 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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509 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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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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How to automatically reloaded raster layer if source is changed in QGIS?

How to automatically reloaded raster layer if source is changed? (The path is the same but inside source file are changes) I use: qgis.utils.iface.mapCanvas().refresh() but layer not refresh. # ...
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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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How can I specify the CRS of a raster layer in pyqgis?

I manipulating netcdf raster data from the QGIS python console. The metadata of my netcdf file does not provide the Reference system. However I know it is 'EPSG:4326' I am writing a python script to ...
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228 views

Adding new menu item to QGIS Desktop app

I need to add new menu item to the top level menu of QGIS Desktop (2.7.0); I.e. it shall be on same level as "Project", "Edit", "View", "Layer" etc. As far as I know there is pretty nice way how hide ...
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how to for loop a folder to batch clip rasters by polygon using python and QGIS

I am using python and QGIS 2.0. I am trying to clip rasters in a folder by one polygon feature. It's the first time for me using (let's say) "PyQGIS", I was used to arcpy before. Anyway, I don't get ...
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193 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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How to find the polygon inside which a point lies?

I have a layer with polygonal features. Each feature has attributes and values. I also have a list of co-ordinates and I would like to know which feature (or polygon) the co-ordinates lie in. Could ...
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62 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 ...
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412 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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516 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 ...
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1k views

QGIS Zoom from python console

What are the commands to apply all types of zoom (full, on selected layer, etc.) in python console? I'm searching both on pyqgis cookbook and API documentantion, but I'm not finding anything ...
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207 views

Programmatically grouping multiple layers into separate groups using QGIS?

I'm trying to group a large number of layers together based on a common portion of name string. They are a mix of polygons and points. I would like to create individual groups by using part of the ...
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815 views

How to load memory output from QGIS processing?

Many processing algorithms have an option to save output as memory. If ran from toolbox, this works fine, because you can tick the "Open output file after running algorithm" box. Looking at the ...
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284 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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PyQgis question: How to change or set active layer?

Developing a qgis plugin, I found that if no layer is selected in the Layers panel I can iterate over all layers and do anything to them, but "activate" them. Could someone give me a hint please? ...
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803 views

How can I create a new layer from the currrent selection?

Is it possible to create a duplicate layer, only displaying the selection from the layer you are duplicating in QuantumGIS? Simular to ArcGIS -> Create Layer from Selected Features. I looked at "How ...
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578 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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853 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
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1answer
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How to merge shape files with attributes from a python script in QGIS?

I have some shape files. They are all the same kind of shape and all have the same attributes. If I wanted to merge them manually the "Vector/Data management tools/merge shape files to one" works ...
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712 views

How do I set layer transparency in QGIS 2.0 with Python?

I have a raster layer loaded in QGIS and I'd like to be able to set its transparency via the Python console. I'm new to the API and have not been able to find out how to do this. Any help would be ...
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Using in-memory vector layer with QGIS processing / SEXTANTE

I'm trying to run the qgis:clip algorithm from console, but am getting an error when using an in-memory layer as the overlay parameter. Is this to be expected, or am I doing something wrong? Code: ...
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How to zoom to a selected feature with pyQGIS

I want to create a function that selects a feature and zooms to it (similar in QGIS). Therefore there is following function: QgsMapLayerRegistry.instance().addMapLayer(self.vlayer) def zoomTo(self): ...
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77 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= ...
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75 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 = ...
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clip geometries in postgis table if they are inside a polygon

I have polygons defined in KML files just like this one, which I can easily parse. Example: <Polygon><outerBoundaryIs><LinearRing><coordinates> -91.463940,40.372660,0 ...
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871 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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333 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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564 views

How to add a layer group using pyQGIS?

Good morning, I would like to know how I can create a new group in the layer manager using python code, someone could help me?
4
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1answer
163 views

Why can't I copy values from a virtual field to a non-virtual field using PyQGIS?

Using the python console, I am trying to copy values from a virtual field into another non-virtual field. Both fields are integer types but I get NULL in the non-virtual field. I followed the answer ...
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1answer
56 views

Loading same layers every time

I recently started using Qgis python console for Qgis development. My first task is to load the layer and print its attributes.I firstly load a point layer using code mylr = ...
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204 views

What's the most efficient way to load feature attributes into a numpy array?

I am currently working on an add-on that relies on the user choosing fields of tables (that can be from shapefiles, csv or dbf) that are open in QGIS and then making computations with such data. ...
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1answer
139 views

Problem with performance when loading PostGIS layer using pyQGIS

I'm having a question on loading a PostGIS layer into the project from my QGIS plugin. The code is like this: uri1 = qgis.core.QgsDataSourceURI() uri1.setConnection(str(host), str(port), ...
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2answers
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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 ...
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255 views

How to auto-start a pyQGIS thread?

having build some (two) minor plugins, it's now time for me to link a few (perl-) applications to qgis. As there is no perl-interface in qgis I thought the best way to link both worlds together is a ...
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399 views

How change border line to no pen with python console?

From Python console I load a shapefile with qgis.utils.iface.addVectorLayer. How I can remove border lines (change to no pen) in the active layer?
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410 views

How to iterate over selected layers?

In QGis by pressing shift or ctrl keys a user can select multiple layers in toc. How can a python script iterate over selected layers? I'd expect a iface.selectedLayers() but I can find only ...
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746 views

How to Create a raster layer from a numpy array using pyqgis?

I am working on a plugin for Qgis to calculate spatial Kernel density maps. I have all the calculations working, all I am missing is a way to turn a Numpy Array, with density values into a multiband ...
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QGIS: How to load feature (.qml) styles from python? [duplicate]

Possible Duplicate: How to style a layer from console? I'm trying to set the styles for a vector layer by loading the .qml file in the python console. The qml-style file contains all ...
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1answer
681 views

How to load a postgres view using pyQgis?

Under Qgis 1.8 on Windows 7 I have this problem with my pyArchInit plugin: I need to load on the map canvas my geometries from a postgis layer. Till the 1.7.4 version I use the method explained on the ...