All Questions
7,900 questions
9
votes
1
answer
5k
views
Evaluating raster calculator expressions from 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", "outputfile....
- 623
3
votes
1
answer
1k
views
How to use QgsOverlayAnalyzer class in pyQGIS?
I am very new to Python scripting in QuantumGIS, so bear with me please.
I am trying to use the QgsOverlayAnalyzer class in QuantumGIS (http://www.qgis.org/api/classQgsOverlayAnalyzer.html#details) ...
- 31
4
votes
4
answers
1k
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 ...
- 623
7
votes
1
answer
3k
views
Deploying QGIS Python Standalone Application with minimum installation size
I am trying to create a Standalone QGIS Application using python. I was able to create the nice looking shapeviewer application by following the steps here.
Now I would like to deploy this in another ...
- 7,290
5
votes
2
answers
5k
views
Setting up QGIS print composer options from Python console [closed]
If I have a print composer called "ABC", I would like to "tell" its composer that I would like to
update "Map 0" to simulate the "set to map canvas extent" ...
- 499
6
votes
1
answer
1k
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 ...
- 610
29
votes
4
answers
59k
views
Reading 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?
- 309
2
votes
2
answers
4k
views
Where exactly are qgis.gui and qgis.core located?
I'm trying to create a standalone QGIS app using PyQGIS. I'll be deploying it by copying the install folder of QGIS and source folder of my app, and so for the testing purposes I copied QGIS install ...
- 5,157
4
votes
1
answer
549
views
Personal shell launcher for PyQGIS
I have changed a shell launcher found at http://inasafe.linfiniti.com/html/id/developer-docs/platform_windows.html as to fit my wish: setting the system environment variables to be able to use PyQGIS ...
- 3,785
3
votes
0
answers
189
views
How to delete a point with known coordinates in python?
I was wondering if there is a piece of code that does the opposite that setGeometry does and removes a point if there is one at x and y coordinates?
- 323
1
vote
1
answer
387
views
How do you Select an existing vector Layer and Edit it, using python?
I'm developing a small plugin that needs to be able to select a vector layer programatically based on what layer the user has selected. However I'm not sure how to do so.
I believe I found the two ...
- 323
12
votes
2
answers
7k
views
Zooming from python console of QGIS
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 ...
- 157
6
votes
3
answers
20k
views
Extract coordinates from vector layer in PyQGIS
In QGIS, I have made a polygon, and from that polygon I have made a vector grid via research tools-> vector grid. The grid covers the entire polygon.
Now I want to extract these grid points in the ...
- 379
4
votes
1
answer
710
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 ...
7
votes
1
answer
3k
views
Handle add new feature event and/or access feature before commit?
Is it possible with PyQGIS to catch "add new feature" event before commiting changes on the layer? or at least to access new features before commit.
- 319
5
votes
1
answer
1k
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?
- 51
1
vote
1
answer
223
views
Get feature while editing
I have created my custom form for features editing, using layer.setEditForm("form.ui") and layer.setEditFormInit("init") properties. init method receives dialog, layerId and featId as arguments. ...
- 319
3
votes
2
answers
2k
views
Merging polygons at county level to state level?
I have a shapefile that represents counties (admin 2) only, but I need to create a state level (admin 1) polygon file (I'm using QGIS). I will need to sum up (or average) the relevant data at each ...
- 31
5
votes
1
answer
583
views
How to get a list of all projections that are currently available in QGIS via the PyQGIS-API
i'm building a QGIS-Plugin and i want the user to choose a CRS out of a combobox in which the coordinates he would enter into some textfields are represented, so these can be converted into another ...
- 105
1
vote
1
answer
1k
views
How to save an existing LYR file to use a relative path *and* have the LYR be v9.3 compatible?
Not sure if this is possible - I am writing a python script to convert LYR files to use relative paths and save the LYR as a 9.3 LYR file. I can do each one individually, but not together.
...
# ...
- 331
8
votes
2
answers
3k
views
How do I use QGIS python console to iterate through simple layer queries and png outputs?
I'm really new to QGIS coding and I'm having a hard time finding (especially) the api classes/functions to carry out actions of the Query Builder window.
I'm basically trying to do this:
Iterate ...
- 171
1
vote
1
answer
3k
views
How do I copy all feature attributes to a feature in a new layer?
I'm trying to create a new layer in QGIS based on an existing layer. The new features should have all the attributes of the corresponding features in the original layer. I've been trying to use ...
- 6,934
8
votes
1
answer
7k
views
Applying graduated renderer in PyQGIS? [closed]
Just trying to run the following code already given in the pyqgis cookbook to create graduated colors symbology (as in example with 2 classes)
I define the source info for the shapefile but when I ...
- 654
1
vote
1
answer
1k
views
Why do I get 'KeyError: 0' when using Line Intersection tool?
I'm using Quantum GIS version 1.8.0-Lisboa and trying to create intersection point using Intersection tool. (Vector -> Analysis tools -> Line Intersections )
But when I do that for my shapefile, It ...
- 1,097
1
vote
1
answer
769
views
Persisting ArcGIS Network Analysis Route Layer?
I'm using ArcGIS 10.0.
I'd like to be able to specify the location (path) where to create the route layer, for network analysis, when I click on Network Analysis -> New Route. Is that possible?
...
- 1,137
1
vote
0
answers
413
views
DLL problem with PyQGIS
I am having problems with Python Shell importing the module "qgis.core".
When I type "import qgis.core" the Shell ("idle.pyw") gives me this error:
Traceback (most recent call last):
File "<...
- 3,785
4
votes
1
answer
3k
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 *
>&...
- 153
12
votes
1
answer
23k
views
How do I maintain a resposive GUI using QThread with PyQGIS
I have been developing some batch processing tools as python plugins for QGIS 1.8.
I have found that while my tools are running the GUI becomes non-responsive.
The general wisdom is that the work ...
- 1,494
5
votes
1
answer
5k
views
Setting up 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 ...
- 3,785
3
votes
1
answer
512
views
Join GPS points obtained from .GPX file in Python Console
Having loaded the .gpx file into a new layer from python console, I'm unable to access the gps points in the attributes table. Essentially, i'm unable to join these points to form a polygon (buildings)...
- 105
7
votes
1
answer
402
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 ...
- 105
10
votes
3
answers
10k
views
Using QGIS Zonal Stats Plugin from Python Console?
I am using the Zonal Stats plugin in QGIS to extract raster statistics from overlaying polygons (I have shapefiles of species distribution and I want to extract environmental data from within each ...
- 567
25
votes
3
answers
17k
views
Programatically check for mouse click in PyQGIS
I want to know how to check for a mouse click in QGIS. I am trying to write a Python plugin and want to provide functionality similar to the "Select Single Feature" tool that already exists ...
- 375
9
votes
1
answer
6k
views
How to transform a selected multipart feature into singlepart features while editing in QGIS?
There are several questions and respective answers for how to make a multipart features Layer into a singlepart features one using QGIS:
How to break a single polygon into multiple polys?
How to ...
- 14.4k
5
votes
0
answers
187
views
Is there a way to run the spatial query plugin from QGIS python console? [duplicate]
I want to get all contiguous polygons for every county. In QGIS I can do this manually with a Spatial Query, but for a large data set this result impractical.
Is there a way to run the spatial query ...
- 51
5
votes
1
answer
356
views
QGIS projects - collaboration on different platform
On my computer, I have both - Ubuntu and Windows - operating systems.
Since I work on both of them and QGIS save path to particular layers using absolute path, it's very inconvenient to store ...
- 681
4
votes
1
answer
411
views
Button to add a new line in a non-spatial table without opening the table itself using QGIS?
While using QGIS and having loaded a non spatial table (from PostGIS), is it possible to add a new row to its table attributes without having to open the attribute table first as in here Is it ...
7
votes
1
answer
1k
views
Adding entries to layerlist context menu using PyQGIS
I am implementing a Python based plugin for use with QGIS 1.8.
Most of it's user interface is contained within a QDockWidget but there are some layer specific controls I would like to append to the ...
- 1,494
2
votes
1
answer
183
views
QGIS 1.8 compiled against PyQt 4.8+? [closed]
I'm currently running QGIS on Win7 64bit. My installation says it was compiled against and running against PyQt 4.7.1, although according to the Osgeo4W installer and PyQt4.QtCore.PYQT_VERSION_STR, I ...
- 103
15
votes
2
answers
4k
views
Hiding/showing QgsVectorLayer using PyQGIS
Once created a layer, how can I hide/show it? I can enable/disable the rendering of a specific layer by selecting the checkbox through QGIS, but I need to do it programmatically with PyQGIS.
How can I ...
- 903
2
votes
2
answers
3k
views
How to fix QGIS PyQGIS package?
I have a broken package that is preventing QGIS from loading python plugins, updating itself, or even un-installing.
The main symptom of this problem is the following message that appears when QGIS ...
- 4,274
3
votes
3
answers
4k
views
Changing cursor shape in PyQGIS
I noticed that PyQGIS has QgsMapToolPan() and QgsMapToolZoom() functions, and the cursor shape on the canvas will change to a hand (for pan), magnifying-glass(+/-) (for zoomIn / zoomOut).
I have a ...
- 161
3
votes
1
answer
820
views
Why shapefile loaded in canvas always appear in random color?
I created the simple frame .UI file, compiled with pyuic4, and tried the ShapeViewer.py to load the shapefile "world_borders.shp". However, the map is always loaded in different random colors every ...
- 161
9
votes
2
answers
883
views
How do you obtain the execution times of processes in qgis?
I am working on QGIS. I need to determine how much time QGIS needed to finish a specific task. I have been unable to get execution times for the processes. What is the proper way to get processing ...
- 99
14
votes
1
answer
11k
views
Removing QgsVectorLayer from QGIS plugin
I managed to add QgsVectorLayer in QGIS through a Python plugin, for example:
vl = self.iface.addVectorLayer(uri.uri(), layerName, self.dbConn.getProviderName())
But how can I remove it?
- 903
5
votes
1
answer
833
views
Can I use QGIS plugins in PyQGIS as a stand alone script without iface?
Can I use a qgis plugin especially (openlayers plugin) in stand alone pyqgis script?
I don't find examples, just code using iface but that cannot used in stand alone script.
- 101
4
votes
2
answers
4k
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 ...
- 903
2
votes
1
answer
5k
views
TIN Interpolation using vector layer [closed]
I'm writing a plugin in QGIS and I'd like to generate a TIN surface using a vector layer with x,y and z (interpolation attribute).
The idea is to visualize the same result like in the Interpolation ...
- 21
14
votes
1
answer
6k
views
How to create text labels with background boxes?
I'm trying to create some custom labels for point features in a QGIS point vector layer, and I want to write a python plugin to do it. We need our labels to be presented with color tinted rectangles ...
- 524
2
votes
1
answer
763
views
How to move the QGIS Layerpanel/Dockwidget programmatically
i'm working on a QGIS-plugin and want to move the default LayerPanel/Dockwidget to somewhere else programmatically. More specific: i want to move it into a tab of my tabwidget.
Is this possible? How ...
- 105