Questions tagged [pyqgis]
Python bindings for QGIS.
7,591
questions
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Unable to create empty memory layer for Line layer using PyQGIS?
# Get the currently selected layer
inLayer = iface.activeLayer()
# Get its list of fields
inFields = inLayer.dataProvider().fields()
# Convert its geometry type enum to a string we can pass to
# ...
- 367
1
vote
1
answer
830
views
pyqgis correct activate signal for combo box list
I am a pyqgis user and I am trying to create a QGIS plugin where that plugin have two tabs widgets and two combo box where first combo box have a list from layers and second combo box have list of ...
- 717
2
votes
2
answers
1k
views
Extract corner coordinates of polygon extent in PyQGIS / GDAL
My goal is to extract corner coordinates (i.e. UpperLeft, UpperRight, LowerRight, LowerLeft) from polygon extent using PyQGIS or GDAL.
In ArcPy there is a handy property of an extent class (i.e. ...
- 3,543
2
votes
1
answer
1k
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QGIS python Console Error - list index out of range
I have a text file which has the details of many .tif files which have to be converted to a single merged .vrt file in QGIS Python Console.
text = "W:/04 Tools/07 MapMaker/workingfiles/text.txt"
...
- 729
4
votes
1
answer
569
views
Add Column and Populate using the Python Console
I am trying to add a new column to the attribute table and populate the column with a string, using the python console in QGIS. I have done the same but populating the column with an integer (...
- 105
3
votes
1
answer
994
views
Compute area in square meters rather than degrees using PyQGIS?
If you use the field calculator in Qgis considers the area in square meters, and when using the script gives the area in degrees.
My layer is in the coordinate system WGS 84
vlayer=r"K:/temp/gpp_utm....
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0
answers
205
views
Error in reading project with delimited text layer using PyQGIS?
I have multiple QGIS maps with a KML vector layer and a delimited text layer on top (csv file). I want to save these maps as images using a script as follows in the python console to do this.
for ...
- 121
1
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1
answer
451
views
PyQGIS plugin doesn't work layer list combo box
I want to create a simple QGIS plugin with a simple combo box with list from my layers
in _ _init_ _ :
legendInterface = self.iface.legendInterface()
listLayerName = [i.name() for i in ...
- 1,061
1
vote
1
answer
337
views
Problem executing algorithm
When I run the script below, I got this error:
rps=10000 #RasterPixelSize
layer = iface.activeLayer()
extent = layer.extent()
xmin = extent.xMinimum()
xmax = extent.xMaximum()
ymin = extent.yMinimum(...
- 1,581
1
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1
answer
504
views
PyQgis - Multiple Maps in one page with different layers in each map
I'm trying to make a plugin for printing automatically PDF showing 3 different views from a set of layers in the same page. For this I have created a QgsComposition and I have added 3 QgsComposerMap ...
- 21
1
vote
2
answers
503
views
How to pan/zoom while QInputDialog
I'm iterating over a layer with a python-script in QGIS 2.18. I am going to pan to every feature and ask the user a question regarding this feature an do something depending on his answer.
How is it ...
- 380
2
votes
0
answers
462
views
QGIS Python - Error: Algorithm not found
Trying using the processing toolbox in a standalone python script the needed Algorithm could not be found:
Error: Algorithm not found
Error in sys.excepthook:
Traceback (most recent call last):
...
- 93
0
votes
1
answer
2k
views
QGIS Python - 'NoneType' object has no attribute 'addFeatures'
Trying to convert a python console script to a standalone version of it. By following the general guidelines from QGIS-documentary https://docs.qgis.org/2.14/en/docs/pyqgis_developer_cookbook/intro....
- 93
0
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1
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416
views
Setting current group as active group in PyQGIS? [closed]
While iterating on groups, I would like to set the current group as “an active group” in order that generated layers will be children of this active group.
Is there any pyqgis expression to do this (...
- 863
2
votes
0
answers
62
views
Why isn't my layer loading via pyqgis despite the file name and path being correct? [closed]
I am writing up a python script on PyQGIS to load a point shapefile.
# -*- coding: utf-8 -*-
src = "C:/Users/Aaron/Documents/pygis/Points.shp"
layer = QgsVectorLayer(src,"Localities", "ogr")
if ...
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3
votes
1
answer
5k
views
Autosize custom form window to its content
I've created several custom forms using Qt Designer. My problem is that when I open a form, its window size remains the same as the size of the window of the last form I opened. For example, let's say ...
- 586
2
votes
1
answer
70
views
Strange behavior of QgsScaleComboBox
I am using a QgsScaleComboBox and it's behavior is really strange. I also have 2 buttons in my gui for adding/deleting items. Those are the methods I use for adding/deleting:
Adding:
def ...
- 703
3
votes
0
answers
210
views
PyQGIS expression with many inputs
I try to create some advanced expression using a QGIS plugin for education rules.
I have a simple Gui :
My Gui has 7 line edits for text inputs.
I try to using this Expression:
layer = ...
- 1,119
1
vote
1
answer
192
views
How to measure the response time of a layer WMS/WFS in QGIS
Is there a way in QGIS (or pyqgis) to measure and test the response time of a WMS/WFS layer?
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0
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1
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561
views
Rename Attribute field in pyqgis [closed]
layer.renameAttribute(0,'xxx')
Traceback (most recent call last):
File "", line 1, in
AttributeError: 'QgsVectorLayer' object has no attribute 'renameAttribute'
Can you get me solution for this ...
- 79
4
votes
1
answer
1k
views
Make donut polygons with python in QGIS
I am having trouble in translating the geometry of donut polygons to layer. I am drawing polygons using the list of points as follows;
feature.setGeometry(QgsGeometry.fromPolygon([pLine]))
Here ...
- 707
2
votes
1
answer
482
views
How to show label according to attribute name?
I try to show label name according to predefined in QGIS 3.0 by using pyqgis. I used that code in QGIS 3.0 but last update broke it down. Here is my code:
settings = QgsPalLayerSettings()
...
- 1,581
1
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0
answers
80
views
Using Time Manager and PyQGIS? [closed]
I've just started to use the Time Manage plugin and I was wondering if how compatible it is with PyQGIS. Specifically I was wondering if it was possible to use PyQGis to set up the following features ...
- 401
1
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1
answer
281
views
Installing QGIS on Mac OS X 10.13.2 with Python 3.4
My first time installing QGIS. ReadMe says QGIS uses Python 2.7. So, before I start Do I need to remove Python 3.4 or can I install 2.7 as well?
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3
votes
2
answers
327
views
Removing a joined layer using PyQGIS?
I have two layers that I want to remove using PyQGis as part of a larger script. The first layer I can removed using:
QgsMapLayerRegistry.instance().removeMapLayer( shp.id() )
However, it seems that ...
- 401
1
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0
answers
34
views
.deleteShapeFile isn't delete cpg files [duplicate]
Following this answer.
I notice that the cpg (decoding declaration) file isn't delete using .deleteShapeFile pyQgis function.
Any suggestion on how to delete these files using automatic method?
- 11
0
votes
1
answer
281
views
Connecting from QGIS to PostGIS database using OGR toolbox?
I am trying to write a script to import/append mutiple layers into an existing PostGIS database. I am trying to use the GDAL/OGR toolbox algo "Import Vector into PostGIS database (new connection)".
...
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1
vote
1
answer
441
views
Pyqgis: How to take output from Qgs.ZonalStatistics and join by ID with point layer
What I'm trying to do:
Extract median by a single polygon from multiple GeoTIFF rasters stored in a folder (Solved)
Add each median value to a point shapefile (Match/join by: id column for each point ...
- 637
4
votes
2
answers
2k
views
Export Layout as PDF in QGIS3
I am trying to export a specific layout with python in QGIS3. But I am struggling with the QgsLayoutExport class. How do you use it? How can specify which layout should be exported? This is the code I ...
- 703
2
votes
0
answers
163
views
Passing variables between QGIS plugin and a combobox in layers custom form?
I am developing a plugin that asks the user to enter in "lineEdit" boxes, names of population types, depending on the number of types that they have previously defined.
Once these names are ...
- 21
1
vote
1
answer
257
views
Wrong Minimum Pixel value using GetStatistics function
I want to print the minimum and maximum pixel values of a raster.
When I load the raster Pioneertown.row1.asc in Layers Panel in QGIS, it is showing minimum value = 'nan' and maximum value = '1' .
...
- 729
1
vote
0
answers
93
views
Pyqgis script to join delimited text layer on KML and create graduated symbols
I need to create multiple maps from QGIS which have the same procedure and so wanted to write a script. I found little help in terms of how to join delimited text layer to a KML vector layer(of ...
- 121
4
votes
1
answer
4k
views
AttributeError: 'QgsVectorLayer' object has no attribute 'pendingFields'
I have been using the following Python code on QGIS 3 (2.99) to look up fields, for several months
id = feature.attributes()[layer.pendingFields().lookupField('ID')]
And it gives me an error today:
...
- 11.1k
1
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1
answer
250
views
Getting first group name in PyQGIS?
With the following code, I did not succeed to get the first group name of the tree.
from qgis.core import *
from qgis.gui import *
from PyQt4.QtGui import *
from PyQt4.QtCore import *
import os
#...
- 863
1
vote
1
answer
315
views
Access qgis.explodelines in Python (outside QGIS)
I want to access the explodelines function in Python outside of QGIS from a standalone script.
import sip
for api in ["QDate", "QDateTime", "QString", "QTextStream", "QTime", "QUrl", "QVariant"]:
...
4
votes
2
answers
1k
views
How to re-order line layer in QGIS?
I have a line layer that seemingly consists of a single feature. I then ran QGIS's Multipart to Singleparts algorithm (same result as Extract Nodes), so then the result consists of 27 line features:
...
- 2,440
2
votes
3
answers
3k
views
Get current zoom level from QGIS map canvas
Is there any particular way of getting the current zoom level from the map canvas through python code in QGIS environment?
I want to convert coordinates of the cursor and the current zoom level into ...
- 707
2
votes
2
answers
853
views
Python: Extract median by polygon from multiple raster files
What I'm trying to do:
Extract median (or 50th quantile) by a single polygon from 558 GeoTIFF rasters stored in a folder
What I got so far:
Using Python from within Qgis and Qgs.ZonalStatistics I've ...
- 637
1
vote
1
answer
1k
views
Deactivate custom tool when changing layers
I have build a custom toolbar and a tool for a qgis plugin (QGIS 2.18.13) updating a working one in QGIS 1.8. I have several layers loaded, two of them being vector layers for nodes (points) and edges ...
- 81
1
vote
0
answers
40
views
pyqgis plugin error list has not attributes
hello I create a QGIS plugin using pyqgis and I have two buttons in my plugin window button 1(run perform_search(self) function) and button 2(run select_feature(self) function).
to work button 2 ...
- 1,061
1
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0
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560
views
QGIS for Mac: Python dependencies
I am developing a QGIS plugin in QGIS 2.18.15 on macOS 10.13.2 and I am having some troubles with Python libraries dependencies. More specifically, my plugin will require to use an external Python ...
- 111
6
votes
2
answers
2k
views
How do I get the scale of the map item in my Layout(composer) in Qgis3?
I want to get the scale of my Layout that I created. For this I thought of using the QgsLayoutItemMap class. The problem is that the scale method in QgsLayoutItemMap always returns 0.0. I know I am ...
- 703
2
votes
1
answer
385
views
PyQGIS zoom using PyQt list widget
I have created a layer filter Expression to get specific results query
from my layer and I add these results in a list widget using PyQt.
My Expression and my add to list widget work fine (I print ...
- 393
3
votes
1
answer
242
views
Apply transparency on pixels in an image with PyQGIS
I'm trying to grab the pixels that intersect with my polygon shapefile and apply transparency to them (that is, I'm trying to create a hole in my raster)
For that, I get all the pixels that are in ...
7
votes
2
answers
6k
views
Environment variables for QGIS 3 plugin development on Windows
I want to start learning QGIS plugin development, and I'm trying to get set up for Python 3, PyQt5 and QGIS 3.
I've installed QGIS 2.99, qt5-devel and setuptools via OSGeo4W. Now I get stuck on the ...
- 763
3
votes
1
answer
2k
views
Getting a list of all Layouts in QGIS3
I have created 3 print layouts in QGIS3. Now I am trying to get a list of all layouts in the LayoutManager with python. This is how I am trying to do it(this code is executed in the python console of ...
- 703
4
votes
1
answer
819
views
Determine layer visibility with PyQGIS
From some other posts I found that i can determine a layers visiblity by something like
#assume lyr_name the layers name to determine visibity for
l = QgsMapLayerRegistry.instance().mapLayersByName(...
- 541
8
votes
4
answers
3k
views
Getting user's QGIS version using PyQGIS
I am trying to write a QGIS plugin, which should work on QGIS 2 and QGIS 3. How can I find out which QGIS version the user is using, so the right imports are made?
- 703
2
votes
1
answer
1k
views
Writing a Batch File (.bat) Script to run a QGIS Python Script without opening QGIS [closed]
I have saved a python script (named as 'Task3.py'). Currently, I will open QGIS and then run this Task3.py . This python script is saved in C:\Users\Sreeraj.qgis2\processing\scripts\Task3.py .
But, I ...
- 729
2
votes
0
answers
421
views
QGIS fails to open from Python script
I'm trying to get python script to open QGIS and display a project file from a windows batch file, but it QGIS never opens. What am I doing wrong?
batch file contains (I've used this with another ...
- 47