Python bindings for QGIS.

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1k 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 ...
18
votes
1answer
2k views

How to draw perpendicular lines in QGIS?

I have a situation like this: What I need to do is to connect each point to every line that is at most, let's say 200 m, away from the point. In other words, I need to draw a perpendicular line ...
6
votes
2answers
587 views

Cannot run standalone QGIS script

I've been trying, along with this post, to run a script in OSGeo4w Shell, outside of QGIS. But I get the following error: ImportError: No module named qgis.core I have also read the following ...
4
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2answers
1k views

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. # ...
2
votes
2answers
315 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 * ...
2
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1answer
1k 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", ...
10
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1answer
1k views

Is there a way to access QGIS plugins in Python?

Is there a way to access QGIS plugins in Python? I'd like to write a script to do some geoprocessing, and I'd like to use the clip, regular points and convex hull tools in fTools, as well as the Road ...
4
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1answer
1k 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: ...
4
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1answer
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) ...
3
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1answer
969 views

Joining table to shapefile with pyQGIS

Joining shapefiles is a relatively straightforward proess in QGIS using 'add vector join' in the layer properties menu. I can add a csv file as a vector layer, as well as a shapefile, and join the two ...
3
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3answers
2k views

QGIS 2 Python error on Mac OSX

Have just installed newly released QGIS 2.0. I installed the gdal package available at the official kyngchaos site. It seems to run ok, but when the program loads up I get a lengthy error message ...
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2answers
5k views

How to create a new empty vector layer programmatically?

I am new to python and QGIS. I have looked at a few tutorials of python scripts for QGIS. All of them create new vector and raster layers with some existing data source. eg. shapefile or geotiff or ...
8
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1answer
636 views

How to address the new “Task-Completed” QgsMessageBar in Python?

I am really amazed what huge steps the QGIS development has taken in the last months. The new iconset, the improved Print composer and many more changes to be seen in QGIS 2.0 are really awesome! ...
4
votes
1answer
538 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 ...
3
votes
3answers
953 views

How to add QGIS Python API Intellisense support in Aptana Studio3/Pydev

I'm developing QGIS plugins using PyDev in Aptana Studio 3 and I would like to know if it's possible to make it aware of the QGIS API and add some "intellisense" functionnalities when programming. For ...
3
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1answer
456 views

How to update data from external table in real time?

I have been trying for a long time to connect a external table data[csv] through Excel (for exmaple) with QGis with the objective to each time i change any data in table(for example data location - ...
2
votes
1answer
239 views

WMS layer in a QGIS 2.4 stand alone Python script

What is the best way to add a WMS layer on a map, in a stand-alone python script with QGIS 2.4? The methodology explained at the bottom of the official QGIS documentation page seems to be outdated and ...
0
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1answer
388 views

How to obtain rotation field name defined in the Labels “Data Defined” section in pyqgis?

I'm trying to find how to get with the QGIS Python API the layer field name that contain the rotation angle used by a layer to rotate its labels? I know that I can obtain the field name containing ...
8
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2answers
2k views

Split a feature when intersecting with a feature of another layer using PyQGIS/Python?

I have a buffer layer (green polygon) which I want to split to two polygons whenever it crosses a barrier (blue line). I have been trying to use "splitGeometry" method, but I just can't get it to ...
9
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4answers
3k views

How to get features based on their attributes using Python?

How to Get features by their attributes (similar to Iqueryfilter in arcobjects) in Qgis using python? Instead of getting all features and filter it manually, is there any option to use whereclause to ...
6
votes
2answers
2k views

How to use map composer in a stand-alone script?

I'm trying to follow the map rendering section from the pyqgis cookbook, but I'd like to test this as a standalone application. I can do the first part, using simple rendering, but I'm a bit stuck ...
4
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3answers
2k 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 ...
3
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2answers
208 views

How to delete column/field in PyQGIS?

How to remove or delete column fields in a shape file using python?
3
votes
2answers
1k 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 ...
3
votes
1answer
1k views

How to find the nearest line to a point in QGIS? [duplicate]

My question is that given a point and few lines, how should I go about finding the nearest line to the point? I am aware of How to I find the nearest line to a point?, but that isin ArcGIS and ...
3
votes
1answer
724 views

Getting dataProvider from vector layer outside QGIS

I'm using PyScripter to explore PyQGIS API because of it's very handy auto-completion function. I've managed to get a handle on a PostGis vector layer by: >>> from qgis.core import * ...
2
votes
2answers
330 views

QGIS install on Ubuntu 14.04 fails

Following the QGIS installation guide I have tried both UbuntuGIS and QGIS stable, but both fail with the error message: The following packages have unmet dependencies: python-qgis : Depends: ...
2
votes
2answers
1k views

How to read the attribute values using PyQGIS?

What is the way to get the information contained in the attribute table, say in column 2, row 2 using pyQgis?
7
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1answer
2k views

Why can't I import my script from the python console?

i am working with the qgis python console. I usually store all my python scripts into ~/Scripts/python I do have set the PYTHONPATH to ~/Scripts/python in my .bashrc However, I can not manage to ...
6
votes
2answers
906 views

Rendering and Labeling Shapefile with PyQGIS

I've been running into a few problems working with the QGIS API for python. I've gotten more comfortable working in the python console in QGIS but I run into problems when I try to run the code ...
4
votes
2answers
753 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 ...
4
votes
2answers
2k 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 ...
3
votes
2answers
213 views

Join table field with shapefile programatically (via PyQgis)?

The following is currently unsuccessful at fulfilling a table field join to a point shapefile in Qgis. All instances of the join object will print the proper values, and no error is flagged when ...
3
votes
1answer
780 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 ...
3
votes
2answers
500 views

Access Sextante (processing) in standalone QGIS app?

Sextante is addressable via python using the QGIS python console (unfortunately not from outside QGIS). I´m writing a standalone app and want to include Sextante geoprocessing functionality. In QGIS ...
3
votes
2answers
915 views

How to debug 'Layer is not valid error' from Python plugin?

I'm trying to understand what goes wrong with a QGIS python plugin. Basically I'm trying to render a series of POINT. The query works fine, at least giving it by hand from inside PostGIS DB: "SELECT ...
2
votes
1answer
869 views

How to import sextante(processing) for QGIS 1.9 (2.0)

In the current QGIS development snapshot the SEXTANTE toolbox has been merged into QGIS and is now known as "processing". This is a good step, but the previous import command doesn't work anymore. ...
2
votes
3answers
3k views

How can I fix “ImportError: No module named qgis.core”?

First of all, I'm using Python 2.7.3, QGIS 1.8 (Lisboa) on Windows 7 pro 64 bits. Now let's go to the actual question: I have written some code (Python) that works well within the QGIS built in ...
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vote
2answers
177 views

How to install 3rd party python libraries for QGIS on Windows?

How can I use 3rd party libraries on QGIS plugins on Windows? I've developed a plugin that uses rasterio and numpy for a customer, but he's having problems installing rasterio and numpy. Actually ...
1
vote
1answer
71 views

Getting values from Qt widgets and using them for a buffer

I am writing a simple plugin that finds buffer. My gui has 2 combo box and 1 Line edit. The first combo box will have a drop down of values from column 'States' and 2nd combo will have a drop down of ...
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1answer
382 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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vote
1answer
112 views

Run ftools multiparts to singleparts from PYQGIS

Is it possible to run the multiparts to singleparts function from the console with the processing_runalg function? Or is there another way?
9
votes
1answer
2k views

When iterating over a vector layer with pyqgis, how do I check whether a feature is selected?

While iterating over a vector layer using the following code (summerized from the example in the pyqgis cookbook), is there a way to check whether a feature is selected? provider = ...
6
votes
2answers
2k views

Standalone applications using QGIS and environment variables

I've tried going through IRC to see if people can help me out with this, but the medium seems a little clumsy for making any answers clear, so I'm going to try this instead. I would like to program a ...
4
votes
1answer
190 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 ...
4
votes
1answer
819 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 ...
3
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1answer
314 views

How to change the color of a selected feature with pyQGIS?

is it possible to change the color of a selected feature in qgis 1.8? To highlight a feature I use: vlayer.setSelectedFeatures(selectedList) box = vlayer.boundingBoxOfSelected() ...
3
votes
1answer
853 views

qgis.core import error

I would want to use the Qgis api for custom desktop application. When I imported the qgis.core module, I get the following error >>> import qgis.core Traceback (most recent call last): ...
2
votes
1answer
619 views

How to create a QGIS action which copies features between layers?

i tried (i never tried before...) to write a simple python code like action in QGIS on my "XXX" vector layer that: open a layer "YYY" copy the selected feature on my "XXX"layer paste the selected ...
2
votes
1answer
259 views

How can i include program form (created in Designer ) to my QGIS plugin?

How can I include a form created in Designer in my QGIS plugin? And how to get controls values (textbox,label,etc)?