Tagged Questions

Python bindings for QGIS.

learn more… | top users | synonyms

0
votes
1answer
58 views

How to integrate pascal code into a QGIS model or plugin?

I have a console program that is written in pascal (lazarus) that reads in some raster files and parameter values as input. The code use dynamic 2D arrays to represent the rasters. I would like to ...
0
votes
1answer
39 views

How to select a specific area (in a polygon form) determined by some value range in a raster band?

For example, I want create a vector layer with polygons that represents all areas where the elevation is between 500 and 600. Someone has any idea to help me? I'm using PyQgis 2.2.
0
votes
1answer
53 views

PyQGIS: How to send signal to call unsetMapTool()

I've created a map tool to add some functionality to adding point features in QGIS 2.0. I'd like to unset this map tool if editing has manually been terminated by user. I've attempted as shown below, ...
0
votes
0answers
54 views

PyQGIS: QgsMapTool to add point feature

I am having issues programmatically adding point features using QGIS 2.0. I am trying to add a point feature, select another layer's nearby feature, and open the feature form to enter attribute data ...
1
vote
1answer
92 views

QGIS GUI Python Editor Code Running Exception

import sys from PyQt4 import QtGui class MessageBox(QtGui.QWidget): def __init__(self, parent=None): QtGui.QWidget.__init__(self, parent) self.setGeometry(300, 300, 250, 150) ...
1
vote
1answer
130 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 ...
0
votes
1answer
75 views

Programmatically set layer properties Python Init function

Is it possible to set the layer properties Python Init function field programmatically? I've been looking through the qgis 2.2 api but can't seem to find anything on it. Hint, suggestions and ...
0
votes
1answer
75 views

Developing QGIS plugin on Mac - GDAL

I'm developing a plugin for QGIS called DEMtools. It runs fine on my linux machine, but is causing me headaches when run on Mac OS X Mavericks (surprise, surprise). I keep getting segmentation faults ...
0
votes
0answers
46 views

QGIS Python API: SAGA difference algorithm does not split parts

I am using the QGIS Python API in an external script (platform: ubuntu). Everything works as expected. But when I am using the SAGA difference algorithm within the script, there is an issue. The ...
1
vote
1answer
80 views

Import error when utilizing QGIS's Python Init function

Based on the answer to Referencing Qt UIs external to plugin with python. I'm trying to utilize the "Layer Properties / Fields / Python Init function" to execute a file (test_file.py) that is located ...
0
votes
0answers
21 views

'QgsGraph' object does not support indexing

Traceback (most recent call last): File "/home/kasun/.qgis2/python/plugins/floogin/floogin.py", line 246, in findRoutes path=self.astar.astarSearch(graph, start, end) File ...
2
votes
1answer
70 views

Referencing Qt UIs external to plugin with python

I'm developing a plugin that sets up a working environment for a user: loading layers (from db), applying styles and several custom designed (Qt) UI files etc. Primary user interaction is in the ...
0
votes
1answer
43 views

Errors uploading plugin to QGIS python plugin repository

I'm trying to upload my first plugin to: http://plugins.qgis.org/plugins/add/ I keep getting the following error: There were errors reading plugin package (please check also your plugin's ...
0
votes
0answers
40 views

Running algorithm from Processing takes much much longer time than doing it from Qgis GUI

I have a road layer with 32000 features, and I want to find all the intersections. when I use processing->SAGA -> convert polygon/line vertices to points, it is all done in less than 5 seconds. ...
1
vote
1answer
110 views

How to get the map canvas CRS in EPSG code?

This is probably a simple request but I cannot find a way around it: how can I read from python the map canvas CRS? I know how to set it up: canvas = self.iface.mapCanvas() ...
1
vote
1answer
62 views

How to open most recent directory using PyQGIS?

For example, when I add a vector layer, next time that I want to add another layer it opens up where I chose my last layer from. How would one implement this in Python and/or PyQgis? I'm writing a ...
0
votes
0answers
29 views

How can I use the QGIS api on Jenkins

I have a python script with another script for unit testing. I would like to add it to jenkins to get continuous integration. Since I can't pip install qgis, how am I supposed to get the qgis api ...
0
votes
0answers
50 views

Determine Transect line to cover area

I'm near certain this is a solved problem, but I haven't been able to find a solution from searches so here's my situation (probably I'm searching the wrong thing)... I need to compute the ...
0
votes
0answers
28 views

Using QgsSpatialIndex for spatial join

I've written a bit of code to do a simple spatial join in QGIS 2 and 2.2 (points that lie within a buffer to take attribute of the buffer). However, I'd like to employ a QgsSpatialIndex in order to ...
1
vote
0answers
135 views

QVariant is not defined when using addAttributes

When I try to add a field programmatically with the following code: import os.path from PyQt4 import QtGui, QtCore legend = qgis.utils.iface.legendInterface() allLayers = legend.layers() for i in ...
0
votes
0answers
17 views

Is it possible to override default QGIS error messages?

From my QGIS plugin I would like to override/replace one of the the default QGIS error message ("The layer layer_url is not a valid layer and can not be added to the map") with my own message. I have ...
0
votes
0answers
66 views

Accessing CRS info with pyqgis in a standalone application

I'm currently having trouble accessing and defining CRS information in a standalone application. I've read the API documentation and have tried it in the python console in QGIS 2.2.0. The python ...
0
votes
0answers
71 views

How to pass a layer to a thread in PyQGIS?

In my plugin, a user can select one of the loaded layers from a combobox, and then proceed to do further calculations. These calculations are done in a separate thread, "WorkerThread". My question is ...
0
votes
0answers
28 views

Call post-execution command manually in QGIS Processing

I wrote myself a Processing Script and it works fine. Now i want to style the outcome (a new raster layer) with a QgsColorRampShader(), but the problem is that Processing adds the output after the ...
4
votes
1answer
304 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 ...
1
vote
0answers
43 views

QGIS python plugin: PyQGIS for spatial join

For a QGIS 2.0 and 2.2 Python plugin, I am trying to update one layer's field attribute with another layer's field attribute based on geometry function QgsGeometry.within(). My first layer is a point ...
1
vote
1answer
160 views

models from QGIS 2.0.2 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 ...
2
votes
0answers
94 views

PyQGIS: How to color raster layer with existing colorBrewerMap

With pyqgis I have added multiple new raster layers to the legendinterface(). Because i like the ColorBrewer style i want to color some of them with the "Spectral" gradient. How can I do this in ...
2
votes
1answer
93 views

PyQGIS: How to send signal if layer is currently in edit mode

I'm looking for a way to send a signal if a layer is in editing mode. I tried editingStarted(), but it wasn't working. I'd like to do something along the lines of the what I have below, but can't find ...
2
votes
1answer
63 views

Finding Code in QGIS Select Features Toolset

Can anyone tell me in what directory the pre-installed Python scripts for the QGIS selection tools (i.e., Select by Point, Select by Polygon) are found? I am using on a Windows 7 installation of QGIS ...
2
votes
1answer
91 views

How to implement 1:n joins with string attribute concatenation?

I have a question concerning pyQGIS. I'm a QGIS long-time (self-learned) user, but just a pyQGIS newbie. I want to implement 1:n spatial join with attribute concatenation in the table. I have a vector ...
2
votes
1answer
94 views

order layer in QGIS with pyqgis

I´m new in pyqgis. I´m looking for a code to move one layer in TOC to a specific position. Is it possible? Thanks a lot!
1
vote
1answer
165 views

How to use Threads in PyQgis, mainly to keep UI active?

I'm trying to develop a plugin, which does heavy computations and as a result, user interface becomes inactive. I know that I should use threads to keep the UI alive (specifically, I have a progress ...
1
vote
1answer
167 views

How can i use python QGis network analysis library to calculate short path based on speed and distance?

I want to calculate and show short path from starting point to an end point in a qgis python plugin. in my research i stopped by an article about QGis network analysis library; ...
1
vote
1answer
67 views

How to batch interpolate many shp´s to DEM

Here´s the problem: I have about 40 shapefiles of contourlines (type line) and I need to interpolate them to create DEM's (tiff, or better some grid format). To do so, some batch scripting would be ...
0
votes
0answers
58 views

error when running a script for clipping a group of rasters on QGIS 2.2 OS X 10.9

I'm trying to clip a group of raster files on QGIS 2.2 (KyngChaos) running on OSX 10.9. When I run the script I get an error related with the location of the files. I'm wondering if this is something ...
1
vote
0answers
44 views

How to include external libraries with my QGIS plugin?

I'm developing a plugin which makes use of "networkx" library extensively. However, networkx is not part of Python libraries pre-installed in QGIS. Is there a way to include this library with my ...
2
votes
0answers
69 views

Programmatically selecting features by polygon

Expanding upon this post how could you use QGis to programmatically draw a selection polygon and select features within the polygon? I have been using QgsMapToolEmitPoint(self.canvas), to find and ...
1
vote
2answers
221 views

How to calculate distance in meter between QgsPoint objects in PyQgis?

I tried to calculate distance between QgsPoint objects in qgis, i used QgsPoint StartPoint.sqrDist(EndPoint). but i don't find an expected result, i also tried import math ...
1
vote
1answer
105 views

How to populate a combobox with layers in TOC?

I am developing a plugin, and I want user to select one of the loaded layers from a combobox. I've already coded this much: self.dlg.show() layerlist = [] self.dlg.ui.layerCombo.clear() # ...
1
vote
1answer
68 views

How can I use pyqgis to automate a series of field calculations?

I've got a shapefile with about 30 fields that I'll need to update from time to time by importing a CSV with new data, joining it to the shapefile, and using the field calculator to carry the new ...
0
votes
0answers
83 views

How can I get the set of points (cloud) that are a given distance in SpatiaLite?

I have a set of points and need to get the groups of points that are within a distance x. Ie, determining the point clouds that are up to the distance x from each other. Any help would be ...
1
vote
1answer
81 views

reproject vector layer with pyqgis with new CRS does not worl

In QGIS I am running a script in th python toolbar to export all visible vector layers to a GEOJSON with this snippet: canvas = qgis.utils.iface.mapCanvas() allLayers = canvas.layers() for i in ...
1
vote
0answers
75 views

Programmatically modify layer datasource on project save event (QGIS)

I have a QGIS plugin which allows users to add WFS/WMS layers to the map. I would like to be able to scramble the user ID part (token) of the uri when the project is saved/closed and then use my own ...
2
votes
0answers
111 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): ...
1
vote
0answers
40 views

can not delete file after using runalg function

I my plugin I use the runalg function: processing.runalg("qgis:clip",filepath + "/temp2.shp", Layer, filepath + '/' + layerName) vlayer = QgsVectorLayer(filepath + '/' + layerName + '.shp',layerName, ...
0
votes
1answer
183 views

Save as .csv with coordinates in both QGIS 2.2 and PyqGIS

These questions have been asked before, but since they are not answered I will try to pick up the ends here. 1) First, as stated here: QGIS 2.2 saving layer as CSV with GEOMETRY=AS_WKT not working ...
1
vote
1answer
69 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?
0
votes
2answers
216 views

How to copy attribute values of fields in selected features of one layer to another Qgis programmatically?

I am trying to get the values of attributes of the selected features of a layer field by field and copy to another layer that I created in qgis with pyqgis. Is here a example for this. Every example ...
2
votes
2answers
100 views

pyqgis: AttributeError: 'QgsRasterLayer' object has no attribute 'drawingStyle'

qgis gurus. I have a question about pyqgis and hopefully I can get some advise here. I am following http://www.qgis.org/en/docs/pyqgis_developer_cookbook/intro.html. In python console after a raster ...