Python bindings for QGIS.

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1answer
71 views

How to get into the Python API of QGIS?

After a few hours I am about to give up on finding a kind of documentation for the QGIS Python API that actually works/gives the correct information. It is obvious that there is no actual code ...
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0answers
57 views

QGIS processing framework SAGA NaturalNeighbor in external Python Script - No Output

I want to build a little script, which generates a NaturalNeighbor grid based on a point Shapefile. The script runs within my PyDev environment without any error messages, but no outputfile is ...
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0answers
33 views

Create “grid” of polygons with the same 3D area based on an underlying raster variable (e.g. DTM height)

This could apply to point or raster values but imagine a raster of a continuous variable such as height (DTM). Is there a way to create a complete coverage of polygons that will have an equal area, ...
3
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0answers
60 views

Find Polygon in “Layer A” containing Polygon in “Layer B”

I haven't found yet someone with the same problem, so I'm posting a new question. The topic seems quite standard, so I'm sure there's a way to do it in QGIS. I have two layers: Region Layer Postcode ...
2
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2answers
57 views

Problem with accessing the layer legend using pyqgis in QGIS 2.4

I'm trying to clear the layer selection using pyqgis. It appears to me that: lgd = iface.mainWindow().findChild(QtGui.QTreeWidget, "theMapLegend") Doesn't work in QGIS 2.4 to access the layer ...
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0answers
29 views

Pyqgis, Plugin development issues

I am new in the pyqgis world... I am trying to adapt the Geocoding Plugin developed by Alessandro Pasotti to a new plugin. I have been dealing with the following issues and I think you have the ...
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0answers
39 views

ERROR 6: EPSG PCS/GCS code error when running QgsGeometryAnalyzer().buffer

I am trying to buffer points from a FileGDB in a PyQGIS script. I setup my environment with the following batch file and run the python script below. The problem is that I get ERROR 6: EPSG ...
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0answers
24 views

Problem with Performance when accessing selected Features from PostGIS layers in QGIS using Python

I have 2 PostGIS layer in my QGIS project. They have about the same amount of data and a similar structure except that layerX has its PK on a single column and layerY has its PK on 4 columns. When I ...
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0answers
90 views

How to correctly render a raster Layer to GTiFF with QGIS python console?

I am trying to render a map from a raster layer. As recommended in pyqgis cookbook and here(osgeo.org) I use QgsMapRenderer(). I am able to produce a picture but it has not appropriate extent and ...
1
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1answer
90 views

How to properly import QImage from PyQt4.QtGui?

I am starting with QGIS python console. Naturally, I came across the PyQGIS Developer Cookbook. While trying to cut my way through it, I encountered a lot of problems with "undefined attributes and ...
1
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1answer
56 views

Rotating geometry to specific angle using pyqgis?

I do not know how to rotate a geometry using pyqgis. Is there any sample/example code available to show me how?
3
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0answers
68 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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0answers
295 views

Ubuntu 14.04 Another ImportError: No module named qgis.core

Issue I feel like this is covered territory here, but the issue is has appeared on two separate occasions for me--first when upgrading from Ubuntu 12.04 to 14.04 in May. I got it fixed then, but I ...
0
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0answers
93 views

How to save a WMS layer at multiple resolutions as .tif using pyqgis

How can I export a wms-map-extent as a .tif from QGIS? Is it possible to call the "Save as.." function of a WMS-raster-layer from pyqgis? (E.g. by simulating right-clicking the layer, choosing "Save ...
2
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1answer
81 views

Cannot load postgis layer from sql string in pyqgis

I'm trying to load a layer using the following code in qgis python console: sql = "(select the_geom, ID from mytable)" uri = QgsDataSourceURI() ...
2
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1answer
33 views

How to store a password during one QGIS work session?

I'd like to get into qgis-plugin development, but am rather new to both python and QGIS development. I intend to write a plugin which connects data from a mysql database to shapefiles. As the data is ...
1
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1answer
152 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 ...
0
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1answer
62 views

QGIS Python console - save image from bounding box

I want to save an image from QGIS but the save image functionality feels limited. My question is if it's possible to use the python command line to save an image at a specific zoomed in scale and to ...
1
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1answer
38 views

pyQGIS - Data Source is Invalid

Why I am getting Data Source is Invalid in python console of QGIS when running: vlayer = QgsVectorLayer("home/sanjayr/Desktop/india-latest.shp/buildings.shp","sanjay","ogr") I am using QGIS 2.4 on ...
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0answers
41 views

Clipping between features within a single vector?

Is it possible (via the Qgis API and friends), to clip polygonal features within a single vector layer? The hope is to accomplish this without having to duplicate the feature into a new layer. ...
3
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0answers
91 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
63 views

Using two different Python versions for QGIS scripting?

I´m intending to learn scripting with python in QGIS, but I have a couple of questions. I'm using Python 3.4 for learning which is installed in my laptop, but QGIS is using Python2.7 How could I ...
1
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1answer
127 views

Why is feature.geometry() None in my user-defined expression function?

I'm trying the user-defined expression functions for QGIS, as listed on Nathans blog: http://nathanw.net/2012/11/10/user-defined-expression-functions-for-qgis/ I always get the feature.geometry() as ...
2
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1answer
34 views

QGIS Processing - Additional Creation Parameter for GdalWarp

I am having a hard time getting the "Additional Creation Parameters" to work when using GdalWarp through the processing toolbox. I am trying to set the nodata value to 0 for the output raster. ...
2
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1answer
114 views

PyQGIS - Start/Stop Editing with data Provider - Commiting changes

I want to edit a specific field for a QgsVectorLayer, within a QGIS application. I am facing inconsistent results from my code, ie: changes are not alway commited. Please could someone point me to ...
2
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0answers
21 views

Refreshing “layer render order” widget

i made changes in the render order of my map canvas using a : qgis.utils.iface.mapCanvas().setLayerSet(a) "a" being a list of QgsMapCanvasLayer My code is working as expected (i see result on map ...
5
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1answer
150 views

QGIS Processing Progress

I have been developing a python plugin that uses Processing algorithm for raster calculations. I want to support the gui with progress bar. How can i connect Processing job to progress bar? I found ...
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1answer
70 views

Programmatically export a Qgis project

I have a QGis project that I programmatically modify using the Python xml.etree library. Now, I would like to know if it is possible to add few lines to my script in order to export the modified ...
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0answers
69 views

Retrieve a point coordinates from map canvas using QGIS API

I'm trying to build a plugin that firstly captures the map coordinates. I have tried to adapt the map tool explained in this post: How to programatically check for a mouse click in QGIS The code I ...
2
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0answers
38 views

Memory layer or QgsVectorFileWriter Error?

Currently this excerpt of code will not save to file (as it is supposed to). The memory layer is visable and editable. Yet even when manually saving the layer, any priorly added features ...
1
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1answer
116 views

QGIS 2.4 plugin PyQT qWebview javascript interface problem

I have a QGIS plugin which contains a qtwebview and Javascript communication between the page and the plugin. It is working perfectly with QGIS 2.2 but not with 2.4 (both QGIS versions share the ...
3
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1answer
63 views

QgsMapCanvas.reresh() does not reload new wfs layer features, but panning does

I have a wfs layer loaded in a standalone QGIS app, which I am updating by running a database query on the view it is based on. The feature is added with no problems and I reload the layer with: # ...
3
votes
1answer
46 views

Changing attribute values in a memory layer

I'm trying to change attribute values in a memory layer. My memory layer is defined in this way: pro.addAttributes([QgsField("nom", QVariant.String), QgsField("valeur", QVariant.Int)]) I made ...
1
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1answer
131 views

Import shapefile is not working in pyshp?

I am just trying to use "pyshp" package to open shapefile in Python and use the Attribute data for further development. Firstly I have downloaded pyshp package for python 2.7 and installed it in my ...
1
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1answer
42 views

How to set QGIS options in standalone pyqgis application

I have a standalone application which uses the QGS api to view and query map layers. One layer is a WMS-C layer which automatically caches tiles which is great. I want to also activate a setting which ...
2
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0answers
35 views

access point layer representation in qgis with pyqgis

I am exporting the style of a categorized point layer with qgis: unfortunately my code only extract the size of the symbol in the definition of the properties of the layer but not the ...
3
votes
1answer
58 views

PyQGIS esri ascii grid to .bil conversion

Esri ASCII GRID can be converted to esri .bil format by following way in a desktop From QGIS desktop menu-->Raster-->conversion-->Translate(convert format) How can I write a python code because I have ...
3
votes
1answer
36 views

Why is the SelectionChanged signal triggered every time i click on the layer?

i'm making some experiments with the SelectionChanged signal of a QgsVectorLayer. i try this piece of code : curLayer.selectionChanged.connect(self.test) and "test" print a warning message. The ...
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0answers
26 views

PyQGIS standalone gdal_ECW_JP2ECW.dll error

This is my code in a batch file My error messages are gdal_ECW_JP2ECW.dll error unable to open EPSG support file gcs.csv Thanks in advance REM Change OSGEO4W_ROOT to point to the base install folder ...
1
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1answer
85 views

How to delete column/field in PyQGIS?

How to remove or delete column fields in a shape file using python?
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0answers
16 views

Pyqgis 2.2 : get signal on feature added : error message

For my pyqgis plugin 2.2, I try to: def logFeatureAdded(self,layerId,addfeatures): message = str(layerId) + " has features added: " for feature in addedFeatures: message += str( ...
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2answers
132 views

Pyqgis 2.2 : zoom to layer extent?

Regarding my plugin pyqgis 2.2, i can load a vector layer succesfully. But when i try to zoom to the layer extent it does not work. How to do in order to zoom to the layer extent? Thank you very ...
2
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0answers
52 views

How to add a TIF raster layer programmatically?

This is my code whenever i try to load .tif image it shows layer is not valid,QgsRasterLayer always return invalid layer (I am using linux 12.04). QString myFileName = ...
0
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0answers
56 views

Get signal on edited feature?

Regarding my pyqgis plugin 2.2 , I've implemented signal on a vector layer event successfully. For instance, whenever i create a new feature, i can read a new basic message appeared via QGIS logging ...
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0answers
47 views

Is there a way to take control of the mouse pointer using python in QGIS?

i would like to take control of the mouse pointer in QGIS (for example constraining it to a given extent...) Is there any way to do that using PyQGIS ? Thanks !
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0answers
33 views

Pyqgis :2.2 : link between a signal and an event

I'm writing a pyqgis 2.2 plugin with qgis 2.2 I succeeded in accessing and displaying vector data (geometries & attributes). I succeed also to create a 'beforecomitechanges' signal ( emitted, ...
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1answer
82 views

Pyqgis 2.2 : How to allow editing on layer and features

I'm writing a pyqgis plugin with qgis 2.2 I succeeded in accessing and displaying vector data (geometries & attributes). Now I would like to allow editing for all my layers and all features ...
2
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0answers
49 views

Modifying properties of Attributes Table in QGIS?

In my QGIS project I'm using vector layers that require a lot of data inputting/editing. The problem is that some of the data I'm inputting varies greatly in matter of length and structure (various ...
1
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1answer
55 views

How to move a layer in QGIS Toc above an existing group?

If in QGIS TOC a group already exists and I add a new layer via QgsVectorLayer* lyr= mQGisIface->addVectorLayer(uri->uri(),Title, myProviderName); the new layer will be inserted within the ...
2
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1answer
69 views

How to add labeling to a polygon layer?

I'm trying to add labeling to a polygons vector layer called "myVectorLayer". It does not give me an error but the labeling does not appear. palyr = QgsPalLayerSettings() ...