Python bindings for QGIS.

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226 views

Unable to load .gpx file from Python Console

I'm trying to create a plugin which will extract the gpx files and load them onto the active layer window in QGIS. While I'm able to load it using the QGIS GUI from Layer>New Vector Layer, I'm not ...
7
votes
1answer
88 views

How to index large VRT files in QGIS?

I have a large number of small tiles merged into a single VRT. The rasters are only viewed at large scale, so only a few of them are visible at the same time. The map refresh in qgis is slowing down ...
7
votes
1answer
313 views

Is it possible to use memory layers in QGIS processing algorithms?

I am building a QGIS plugin that connects to a MySQL database in the local network, and then adds a subset of one of the tables to an in-memory layer; the subset is based on data currency (only taking ...
7
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0answers
336 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 ...
6
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3answers
3k views

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 ...
6
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1answer
2k views

QGIS python - identify and highlight features programatically

In QGIS there is an option to select features of a selected layer using a "identify feature" tool. Then the feature get highlighted in a different color and attribute dialog is poping up. like that i ...
6
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2answers
2k views

How to change the color of a vector layer in pyQGIS?

Is it possible to change the color while adding a vector layer? I have a vector layer with water areas and want to load it with a blue color style. The layer is added with: ...
6
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1answer
2k views

How to evaluate raster calculator expressions from the console?

How can I execute from the console an expression that should be used with the raster calculator? I'm searching for something like this: qgis.someRasterCalcClass.evaluate("boh@1 + boh@2", ...
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4answers
3k views

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 ...
6
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2answers
3k views

How can i obtain the data of one selected feature in QGIS using python?

I have a problem / question regarding python and QGIS. Is it, and yes how, possible to get the data of one selected feature in QGIS using python? In my example I have a layer which shows some parcels ...
6
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2answers
248 views

Skeletonize vectors in QGIS/Python

I am trying to find a tool to create a skeleton of a large vector dataset using QGIS and its bundle. It should be directly programmatically callable through Python or commandline (QGIS, GRASS, OGR ...
6
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2answers
3k views

How to get field names in pyqgis 2.0

I am trying to change an plugin from QGIS 1.8 to 2.0. In the 1.8 version I create a table of the field names like this: layer = vlayer provider = layer.dataProvider() feat = QGSFeatrue() allAttrs = ...
6
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1answer
2k 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 ...
6
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2answers
2k 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 * ...
6
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2answers
1k 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 ...
6
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1answer
2k views

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): ...
6
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1answer
3k views

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: ...
6
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3answers
812 views

How do I specify the position, style and units of the ScaleBar in pyqgis?

I would like to add a scale bar to my composition using the python console and then export it to a raster image. I am following the MapRendering tutorial with the "output using map composer " approach ...
6
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3answers
124 views

Counting number of vertices of object on vector layer PyQGIS

First of all, I want to say that I know that similar issue was raised before, but it didn't provide satisfying solution. I need to get the number of vertices of every object on vector line layer. ...
6
votes
2answers
199 views

Adding all Binary Rasters in a Directory Using Raster Calculator in a Standalone Python Script

I have a directory with binary raster files (1 band only) which I need to add in a standalone python script. The problem is the rasters have different number of rows and columns and different ...
6
votes
1answer
109 views

Calling PyQGIS functions from external editors (Linux)

Is it possible to integrate external Python editors (such as KDevelop) with QGIS, so that it would be possible to run functions in qgis.core, qgis.utils etc. outside of the QGIS Python Console? ...
6
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3answers
1k 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 ...
6
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2answers
222 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? ...
6
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1answer
389 views

Efficiently generate Voronoi layers in qgis via Python

The following python commands both appear to function when called in qgis 2.6 to generate Voronoi diagrams: processing.runalg("qgis:voronoipolygons", pointLayer, 1, None) ...
6
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1answer
367 views

How to get the file name of current style using PyQGIS?

I get the name of the current style file using layer.styleURI(). Then, I change the style file using layer.loadNamedStyle(different_filename). However, when I call layer.styleURI() again, it ...
6
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1answer
4k views

Problem with import qgis.core when writing a stand-alone PyQGIS script

I am trying to write a stand alone python script in windows 7 that uses qgis.core and various other qgis libraries. I have found an old question on this subject here: How to write standalone Python ...
6
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1answer
59 views

QGIS crashes when doing a rollback after modifying values of an user-added feature with pyQGIS

I'm developing an addon for QGIS that needs to assign a UUID to any feature as soon as it is added to the layer. I'm using the featureAdded signal to write the UUID in the corresponding field of the ...
6
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1answer
351 views

Getting QGIS python modules to work from PyScripter in Windows 10?

Been trying lots of "solutions" from net research but nothing seems to work. I have the current versions of QGIS from OSGEO and PyScripter 2.5 Based on one of the solutions I tried... import sys ...
6
votes
1answer
1k views

How to write vector layer to csv file with geometry by PYTHON?

I use Python try to write vector layer file to csv file with this code QgsVectorFileWriter.writeAsVectorFormat(mylayer, r'c:\temp\xyz.csv', "utf-8", None, "CSV") It can export to xyz.csv but only ...
6
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0answers
98 views

Can a memory layer be used as an input and/or output with runalg?

Can a memory layer be used as an input and/or output with runalg? With runandload I get this to work: processing.runandload("qgis:mergevectorlayers","memory:bufferOne", "memory:bufferTwo", ...
5
votes
1answer
1k views

How to programmatically associate a layer with a custom UI?

I know it is possible to associate a layer with a custom UI for editing feature attributes using the QGIS interface. But is this possible with Python? This link shows how to achieve the result ...
5
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2answers
2k views

How to automatically reload raster layers 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. # ...
5
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3answers
4k views

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 ...
5
votes
2answers
181 views

Field Editor with Python: select by attribute & open table (QGIS)

I want to search on number values (>, = etc.) within a column and open table for the selected ones. It's an easy task within field calculator, but I want to see how it's build up with the python ...
5
votes
1answer
2k views

How to delete selected features in Qgis using Python

I have a shape file with only one field DN. I would like to delete all features which does not have specific value of the field. Let say the DN can be 1,2 or 3. So far I was able to find out how to ...
5
votes
2answers
2k views

How to show a message box in QGIS?

I am starting to develop a plugin for Qgis using python, which i am very new at, and would like to view some results of variables by displaying a message in QGIS. How can I do this?
5
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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 ...
5
votes
2answers
684 views

How to add a legend to a canvas in a standalone PyQGIS application?

I am trying to develop a standalone PyQGIS application. The map display does not pose any problems, but I do not know how to add a legend to the canvas.
5
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3answers
2k views

How can I define the layer CRS for a memory layer in pyqgis?

How can I define the CRS for a memory layer from the QGIS project settings? vpoi = QgsVectorLayer("Point", "vectpoi", "memory") feature = QgsFeature() ...
5
votes
1answer
239 views

Do I have to publish own QGIS plugins?

If I develop QGIS plugins for my company do I have to make them available to others? I use QT-Designer and think that it also depends on the question how you develop your plugins, right? For example: ...
5
votes
2answers
634 views

How to identify polygon/point shapefiles in python?

I have a script which performs various functions on shapefiles, most of which are polygon-based. However, some shapefiles are point-based and I have to specify where these files are by editing the ...
5
votes
1answer
5k views

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? ...
5
votes
2answers
161 views

How to find disconnected islands in a road network layer, using QGIS

I have a road network layer that can't route from one side of the layer to the other. Topologically, there is no connectivity between the start and end nodes, probably due to missing links. This ...
5
votes
1answer
113 views

Understanding background to Single Hash (#) Vs. Double (##) in QGIS Python Scripting?

First of all I understand the double hash (##) is used to define the Inputs / Outputs in a script's GUI. If there's more to it than that please let me know. In all other Python coding I've done ...
5
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1answer
444 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 ...
5
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2answers
1k 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?
5
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1answer
2k 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 ...
5
votes
1answer
800 views

How do I allow users to select features with the mouse?

I am using PyQGis API to create a custom application. How do I allow users to select features with the mouse? Is there a mapTool for this? Surely with a product as powerful as QGis there must be. ...
5
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1answer
66 views

Keep UI Settings for a QGIS plugin

I'm writing a plugin that interacts with external software (hydrological models). One of the dialogs has a lot of entries (parameters to pass to the hydrological software). Once the user has set up ...
5
votes
2answers
110 views

QGIS python processing.runalg Clip returns None

I'm writing a script in pyQGIS, which would emulate measurement of a line by "walking" along it with a compass with constant length. I have a problem with the Clip algorythm from processing module, ...