Questions tagged [qgis-processing]
Spatial data processing framework that brings advanced analysis capabilities to QGIS.
1,625
questions
0
votes
0
answers
16
views
CrossTabManagerError appears in creating changes map while using MOLUSCE Plugin in QGIS
I'm using QGIS 2.16.0 Wein and the Plugin MOLUSCE(ver. 3. 0. 13). Now I'm trying to create a change map, but get the following error.
Traceback (most recent call last):
File "C:/...
- 31.4k
2
votes
1
answer
75
views
Generating offset line from MultiLineString in QGIS
I have a MULTILINESTRING in my CSV file, and I want to generate a copy of it offset to the right by a few meters. I've run Single Sided Buffer, and Offset Lines, and neither of them seem to generate ...
- 31.4k
3
votes
0
answers
104
views
+50
Specifying compression for native raster Processing algorithms
I use QGIS' native native:fillnodata Processing tool to fill NODATA cells in a raster with a specific value. This works well but the resulting file is huge.
How can I specify raster compression for ...
- 107
0
votes
0
answers
14
views
Creating QTiles in QGIS
I am trying to follow the directions to create a base map with QTiles in QGIS. Here is the link with instructions for reference:
<https://astuntechnology.github.io/qgis-tutorials/html/en/docs/...
- 65k
0
votes
0
answers
25
views
Problem Polygon Line Intersection - SAGA QGIS
I have a ShapeFile with a series of polygons (ex: the yellow line is the common boundary between 2 polygons). I have another ShapeFile that contains a line (Pink) which crosses the limit line of these ...
- 25
4
votes
1
answer
42
views
Problem to interface a script with python in QGIS
I have a problem with some python code that I'm trying to interface into qgis. This script works via python console but not when I try to implement it as a tool.
The goal of the code is to get data of ...
- 76.1k
1
vote
0
answers
33
views
RuntimeError: wrapped C/C++ object of type AlgorithmDialog has been deleted - Custom Processing Script
This is my first real project for QGIS so I'm completely in the dark for the best practices. I'm working on a custom processing script within QGIS. Simply put the script uses the 'extract by location' ...
- 19.9k
0
votes
0
answers
37
views
QgsProcessingAlgorithm.initAlgorithm() is abstract and must be overridden
If I create a processing script from the template provided, I get this error (that is spammed every time I open QGIS)
I couldn't figure out a way to get rid of it
(despite the error, the scripts I've ...
- 2,668
3
votes
1
answer
207
views
Where is the source code for the Processing Plugin "Buffer"?
Context: In the Graphical Modeler, I want to use an attribute of my source layer to set the buffer distance parameter. Using the "Pre-calculated Value" option, and entering the attribute ...
- 65k
2
votes
0
answers
919
views
QgsVectorLayer.IsValid() always returns False?
I'm writing a standalone Python script which involves some geoprocessing using qgis libs. Unfortunately, I couldn't manage to properly instantiate a vector layer - every time i run .isValid() on ...
- 76.1k
4
votes
0
answers
545
views
Looking for definitive way to enable ALL QGIS module access in VS Code (Windows 10)
I'm having trouble importing and getting code inspection/autocompletion working for all the PyQGIS modules I need to do scripting in VS Code. After looking at these questions:
Understanding qgis....
4
votes
1
answer
319
views
Using memory layer as input with processing runalg in PyQGIS
My first processing runalg creates a memory layer as output.
I need to use this layer as the input for the second runalg.
#first
processing.run("qgis:fieldcalculator", {
'INPUT': '...
CommunityBot
- 1
1
vote
5
answers
1k
views
Set display name of vector layer in processing script
I have a processing script (QGIS 3.12) that extracts values from an input table using the native:extractbyattribute algorithm. This produces a temporary output table with the display name 'Extracted (...
- 137
7
votes
2
answers
682
views
Changing output layer's name in QGIS processing plugin
I am writing a plugin to convert degree to DMS format. I want to name the output layer containing name of source layer. For example source layer name 'Polygons_WGS84', output layer '...
- 137
3
votes
1
answer
54
views
Run processing tools in Python console
I have created two scripts for my QGIS project. I need to do a manual step after the first script for the second script to work. The second step involves a QGIS tool called "join by nearest"....
- 652
1
vote
0
answers
48
views
Setting output layer names in processing algorithm with stepwise parameter increment in QGIS
I run a processing algorithm in QGIS in an iteration with a stepwise parameter increment from numeric model input A (minimum) to numeric model input B (maximum) by a fixed step size.
Here's what the ...
- 1,235
2
votes
3
answers
244
views
PyQGIS, custom processing algorithm: How to use selected features only?
I want to create a custom processing algorithm with PyQGIS, which is able to take a vector layer as input (in this case of type point) and then do something with it's features. It's working well as ...
- 1,235
0
votes
0
answers
22
views
Extract specific lines from multiple layers
In QGIS I have 16 layers (polygons) which represent the extents of shoreline erosion/recession at different time scales and scenarios into the future. Each layer contains 10 polygons. What I want to ...
- 65k
-1
votes
1
answer
587
views
Semi-Automatic Classification Plugin Error on install required python library remotior_sensus
I have been trying to install the semi - automatic classification plugin but it results with the following error:
semi automatic classification plugin : Error, please install the
Python required ...
- 65k
6
votes
2
answers
721
views
Added raster layers with PyQGIS do not show up
I have a list ("datList") with names of raster layers which I want to add. When I add raster layers in the Python Console everything works fine:
for da in datListe:
layerDir = "C:/[...
CommunityBot
- 1
5
votes
1
answer
123
views
Installing a custom Processing algorithm for all users
QGIS is installed for all users on a Windows machine.
A custom Processing algorithm stored in a file named alg.py should be made available to all those users by storing it in that QGIS installation. ...
- 3,342
2
votes
1
answer
177
views
Data matching between 2 layers which do not overlap
I would like to know how a vector layer can takes attributes of a field, of another vector layer which is not overlapping.
For example, there are 2 vector layers, test_1 (2 records A,B) and test_2 (3 ...
CommunityBot
- 1
3
votes
1
answer
64
views
What is the equivalent of native:aggregate() in QGIS Field Calculator?
I have two layers which I want to connect using the aggregate() function with the Field Calculator. I can do this using the processing tool:
processing.run("native:aggregate", {
'INPUT' :...
- 31.4k
0
votes
1
answer
169
views
Using r.reclass.area.lesser in QGIS?
I want to reclass small areas in QGIS 2.18, but it seems to fail calling the algorithm in GRASS GIS. The interesting lines from the Log of the tool:
...
C:\PROGRA~1\QGIS2~1.18\bin>g.region n=...
CommunityBot
- 1
5
votes
1
answer
243
views
Using Python code from QGIS 3.x Graphical Modeler in console?
I want to use "Join Attribute by Location (summary)" processing algorithm in Python console of QGIS 3.10. After design my algorithm process (join sum of field name "abc" form layer 2 (point layer) to ...
- 13.9k
0
votes
0
answers
24
views
Fill sink problem in deliniation
Why doesn't the Fill Sink algorithm appear in the toolbar? How can I make it appear? my qgis is 3.34 version
1
vote
1
answer
3k
views
ModuleNotFoundError: No module named '_gdal' ... but I have GDAL
I'm really at my wit's end with this. I'm on a Macbook running Sierra 10.12, so I used the KyngChaos installation of QGIS 3.8. I followed the instructions in the ReadMe (added the PATH variable), and ...
CommunityBot
- 1
0
votes
1
answer
22
views
QGIS Whitebox processing provider in standalone
When developing an application (e.g., custom algorithms) that rely on a custom processing provider (e.g., WhiteBox tools), it can be useful to run/develop as a standalone app (i.e., not within QGIS). ...
- 174
2
votes
2
answers
151
views
Creating vector grid in QGIS for two different polygons without overlapping
In QGIS I have the data for all the continents except Antarctica. Now I want to create a grid of size 1km * 1km for each country however the problem I am running into is that if I take two ...
- 29.3k
1
vote
0
answers
34
views
QGIS processing plugin doesn't show layers in dropdown menu (QgsProcessingParameterFeatureSource)
I'm trying to work up a minimal processing plugin. I'm using the basic plugin program generated by Plugin Builder. The only change I've made is to configure the input of the feature source to be a ...
- 11
0
votes
0
answers
29
views
Process to Open Multiple Vector Tools at one time
I don't even really know how to ask this question correctly, but I have a process that I am doing which requires quite a few steps of opening a vector tool, running it, taking those results and ...
- 65
0
votes
0
answers
16
views
Parameter not respected in formula (in PyQGIS script exported from QGIS Processing model)
To demonstrate my issue with @parameters in formulas: I created a simple QGIS Processing model where an input_layer is buffered with buffer_distance. In addition the buffer_distance should be written ...
- 323
0
votes
1
answer
817
views
Converting TotalStation native field data to coordinates
I'm trying to convert field data from an older Sokkia TotalStation machine, to coordinates. I've looked at Copan but as far as I can tell it doesn't support the file format.
There are some outdated ...
CommunityBot
- 1
1
vote
1
answer
291
views
Not able to create memory layer while running processing algorithms
I am trying to run processing algorithms in Python code editor inside QGIS. Here is my code:
zones = QgsVectorLayer('C:/Users/pamidiashoka/Downloads/OP_Pen/boundaries.shp', 'zone boundaries', 'ogr')
...
CommunityBot
- 1
3
votes
1
answer
319
views
Which output data type to choose in QGIS SAGA Raster Calculator in Batch Mode?
I have 5 years of MODIS13Q1 NDVI .tiff images for time series analysis. I want to multiply all the images with the scale factor of 0.0001 before using them. In order to process all at once I try to ...
CommunityBot
- 1
3
votes
1
answer
731
views
QGIS 3 Graphical Modeler pre calculated values using Advanced Field Calculator
I have a new model that tries to create a new column using the Advanced Field Calculator and pre-calculated values. I just seem not able to get the syntax right on how to populate the attribute using ...
CommunityBot
- 1
5
votes
6
answers
11k
views
Plugins repository is unavailable
I'm using QGIS 2.18.20. On MacOS High Sierra 10.13.5
Only recently I haven't been able to find uninstalled plugins. The settings show the repository is "unavailable".
I'm not using a proxy. I've ...
- 1
0
votes
3
answers
97
views
Random polygon color with rule based styling
I am using a rule based styling only to show certain polygon which match with below filter:
"NAME_2" = 'Probolinggo' OR "NAME_2" = 'Kota Probolinggo'
The layer has thousands of ...
57
votes
10
answers
89k
views
Missing Processing Tools in Vector Menu of QGIS
I'm missing all the usual processing tools in the Vector menu in QGIS 2.16 (e.g. Vector Overlay, Analysis, etc). They do appear in the processing toolbox but there's no sign of them in the Vector menu....
- 2,668
3
votes
1
answer
43
views
PyQGIS: Remove a legend item NOT the whole layer from the project
I have a number of vector layers and, occasionally, an image basemap.
I am creating a layout programatically based on this data.
I have a legend but I have zero want or need for the basemap raster ...
- 76.1k
0
votes
1
answer
78
views
Correct way to specify Inputs and Outputs for QGIS processing scripts that use custom widgets?
Processing scripts do not allow parameter inputs to be changed by other parameter inputs. This can be overcome by defining a custom widget which does have the desired interactions, then using a '...
- 20.6k
1
vote
1
answer
358
views
Checking SAGA version from a python plugin in QGIS 3.4.0
I use QGIS 3.4.0 on Windows and I want to verify SAGA version with processing.algs.saga.SagaUtils.getSagaInstalledVersion(). But I get an error:
module 'processing' has no attribute 'algs'
This was ...
CommunityBot
- 1
0
votes
0
answers
25
views
QGIS - Processing framework - QgsProcessingParameterFeatureSource type
I use QGIS to build a script with processing framework. In processing toolbox menu I wan't to "filter" data with data types. I can filter point/line/polygon vector layer but how can I filter ...
- 1,576
0
votes
1
answer
34
views
Create one-sided-ellipsoid from 'geometry by expression'
I am looking for a way in which, I can create a buffer around a point.
The buffer is meant to be a semi-ellipsoid.
In theory it should be a mixture of 'single_sided_buffer' and 'make_ellipse' ...
- 3,795
1
vote
1
answer
2k
views
Enable single feature selection in QGIS using Python
I want to enable single feature selection using Python. I want to make a script in Python that will first enable single feature selection, and then it will return the id of selected feature. I have ...
- 1
6
votes
3
answers
13k
views
How to delineate watersheds in QGIS?
I am using qgis 2.14.17 with ubuntu16. Having as input data a DEM of the region and a river network.
In the manual of qgis they suggest to use a toll of qgis: Catchment area (Parallel); I dont have ...
- 96
1
vote
1
answer
270
views
Using the "Selected Features Only" checkbox with QgsProcessingParameterFeatureSource in PyQGIS script
I'm working on a custom QGIS Processing algorithm, and I'd like to include an option for the user to process only the selected features in the input layer by using the checkbox "Selected Features ...
CommunityBot
- 1
0
votes
0
answers
36
views
The map color display in GEE and QGIS is different
I'm new to in Google Earth Engine and QGIS. Lately I try to export map from Google Earth Engine and then i opened the map in qgis. Sadly, the map color in Google Earth Engine is not the same in QGIS. ...
- 19.9k
3
votes
1
answer
711
views
How to close open files after processing.runalg() command (Qgis: Error No 24)
I'm creating a pyqgis script. In this script I use the processing.runalg command several times. The problem is that these processes are within a for loop. After several iterations, the error number 24 ...
CommunityBot
- 1
1
vote
1
answer
76
views
Choosing the correct predicate for calculating mean patch area per grid cell in QGIS
In QGIS, I have two vector layers - one vector layer is basically a grid, where each grid cell is of size 100x100m, while the other vector layer is Building Footprints data (a collection of polygons ...
- 2,668