Questions tagged [qgis-processing]
Spatial data processing framework that brings advanced analysis capabilities to QGIS.
1,583
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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 '...
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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 ...
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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. ...
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58
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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 ...
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QGIS - QgsProcessingParameterFeatureSource - Filter input layer
In QGIS, I try to write a script for a custom toolbox. I'm using the processing framework logic and following official documentation. I add an input vector layer, but I can't handle it has a ...
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Labelling for multiple layer [closed]
There is any option to label for multi layer attributes?
We can set multiple labels in single layer by using ||'\n'|| this, but I trying to label for multiple layer is that possible?
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QGIS processing script crashes while trying to set layer styles
So i recently tried to improve my script for automatically setting the style of vector layers from a folder filled with ".qml" files. It usually crashes around the 4th or 5th layer, and if i ...
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28
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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' ...
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21
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processing.run wont work with filter on layer
I have a pyqgis script in my plugin. There I like to execute a process:
new = processing.run("native:splitwithlines", {'INPUT':QgsProcessingFeatureSourceDefinition('table-path-to-the-db', ...
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27
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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 ...
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59
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How to chose a Vector layer, chose a field, then chose values using parameterAsEnums
I'm coding an archaeological site prediction model. Researchers are able to load multipolygons (i.e. soil type, landform), choose the field to 'weight' or 'rank'. My data has both soil and landform ...
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Buffer coming out to be a circle
I have been trying to make a buffer for the roads but the buffer is coming out to be a huge circle. Both the project coordinates and Shapefile coordinates are the same. Any pointers on how to solve ...
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2
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116
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Accessing layers from QgsContext transferred by completed QgsTask using PyQGIS
We have a headless QGIS standalone script that needs to run some I/O intensive layer retrieval tasks, each as parallel background threads before doing further GIS processing.
We are invoking our ...
- 275
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73
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'Could not load source layer for INPUT: invalid value' error in PyQGIS
I'm trying to implement a processing plugins in QGIS 3.28.9, but when I hit Run, it gives me a message that my polygon layer is not a polygon layer, but, it is a polygon, in fact. Can someone help to ...
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40
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IDW processing not running as expected in standalone script
I'm trying to automate idw interpolations from my database using PyQGIS in a standalone script. I copied the python command from the GUI which is how I got the fields I am using for the algorithm.
...
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52
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NameError: name '__file__' is not defined when getting the path of the current script using PyQGIS
I am trying to run a script in the QGIS Processing Script Editor, but I get the following error:
If I run the script from the PyQGIS console it works thanks to this changes in the console_editor.py (...
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88
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Turning table with lat and long columns into point layer in QGIS
I have a table as a layer in QGIS. It includes two columns: "Lat" and "Long".
I would like to use these as geometry columns.
How would I do this without saving and reloading a ...
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1
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41
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QGIS boundary select smaller polygons that are contained within larger polygon
I have two layers which are perfectly nested. There are dozens of SA1 polygons (thin grey outline - see image attached) within the LGA polygon (thick green outline - see image attached). I would like ...
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PyQGIS 3.22 custom processing script, problem inputting raster and processing zonalstatistics
I'm writing a custom processing script, based on the template, using QGIS 3.22 running on Windows 11. The script runs well as console script, but I want to make it into a custom processing script. ...
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46
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QGIS Plugin - How to automatically add point cloud layers to QGIS at the end of a processing tool?
I'm adding some tools in a plugin that handles point cloud layers.
At the end of a tool, I'd like that the project adds automatically the output point cloud layer created. I tried using ...
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62
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QGIS Python scripting: CRS changes not working as expected
In QGIS 3.28 I have layers with a user defined projection. It is simply Transverse Mercator with a custom central meridian. It shows up as EPSG:10000.
Predictably, $area calculations return NaN.
If I ...
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47
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Using "selectbyexpression" command in standalone PyQGIS script
Is it possible to run "selectbyexpression" in a standalone PyQGIS script? Inside QGIS, I was using iface to add the map to the interface and now I don't know how to run it without using ...
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49
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Creating automatically shortest way network between given point objects via OSM roads (without overlaying line objects) in QGIS
I am trying to automatically generate a grid between point objects (buildings). The grid should be automatically laid over public roads. So far I use the QGIS Processing Tool "Shortest way (...
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30
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QtPy Running a process looping through features
I'm writing an iterator to run a processing on an individual feature of a layer.
In this example: gray region included green bordered cells and black points. I want to run a processing 'count points ...
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23
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Use matrix input for a custom QGIS processing plugin
I'm trying to create a custom processing tool inside my QGIS plugin. The goal is to have:
An input for multiple layers (this is working)
A matrix with a dimension of (nb_layer, nb_layer) that let me ...
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17
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How do I use 'grass7:v.net.spanningtree' from the QGIS python console?
Assume there are map layers named filtered_edges and points. I have written the following in the QGIS python console:
import processing
fe = QgsProject.instance().mapLayersByName('filtered_edges')[0]
...
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28
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Set FID field name in a GPKG processing algorithm ouput
I have a standalone pyqgis script that uses processing algorithms. The final output is a GPKG layer, and I want to define the name of the FID field (that by default is fid).
The relevant code is ...
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QGIS Processing plugin: "NameError: name 'standard_library' is not defined"
I've created a processing plugin using the "plugin builder" in QGIS 3.32. Unfortunately the plugin does not load in processing as it throws an error:
" NameError: name 'standard_library'...
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QGIS Reclassify by Table With Expression
With QGIS Reclassify by Table I am trying to reclassify a raster within a model with a formula that uses statistics from the raster layer I want to reclassify. The formulae I am trying to recreate are:...
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49
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QGIS Processing Toolbox removed Scripts
I was working with adding a new script to toolbox in QGIS but the script wouldn't show up there. Then when I tried again the Scripts tool has disappeared altogether. I have checked in settings and it ...
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40
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Fail during georeferencing an old map
I want to georeferencine an old map, but unfortunately, it failed.
I use QGIS 3.28 LTR to conduct this task. The process which I have conducted as follows:
This is the projection which is written in ...
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Setting numeric values in new field based on length and branches in QGIS
I'd like to know how to set incremental numeric values in a new field of a layer, which has been obtained by "shortest path from point to layer", based on the length and the branches. I need ...
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QGIS shortest path layer to layer
I am trying to find a solution using the shortest path calculation.
My end points are within one layer grouped by an id, for example 10 points have id 1, another 3 points id 2 and so on. My start ...
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45
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Run QGIS tool from standalone Python keeps locks on files
I have a Python application that runs some QGIS processing tools. The tools are called in a loop and I am looking to clean up the tool outputs (shapefiles) in between each iteration. I have found ...
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Accurate Georeferencing of ETRS89-Projected Image and Conversion
I'm seeking assistance with georeferencing the attached image. The image indicates that it is projected in ETRS89, and I have obtained Northing and Easting coordinates by tracing the cross symbols on ...
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Is it possible to write your processing provider in C++ as a plugin?
Added a processing provider to his plugin, the plugin stopped downloading. Maybe c++ cannot be created at all.
plugin.cpp
void MyPlugins::initGui()
{
initProcessing();
}
void MyPlugins::...
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33
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Lizmap geoprocessing missing list of processes to run
I installed QGIS Server and lizmap with lizmap-wps-web-client-module and py-qgis-wps. The button appears in lizmap but the select "choose a process to run" is always empty.
Is there ...
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2
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326
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SAGA option (Fills SInk) option not available in QGIS Toolbox
How do I derive a river network and catchment from a DEM using QGIS?
I'm using the latest version of QGIS 3.30.3 and in it, the SAGA tool (and consequently, the Fill sinks option) isn't available in ...
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129
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QGIS processing parameter using values from layer feature in processing plugin
I want to add an input parameter in a a QGIS processing plugin that let the user choose among all the values in a layer field (or at least provide autocomplete). However, I could not find any ...
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58
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Selection of elements considering features
Still here to propose you a new problem. In the image is shown my situation. In yellow are reperented the streets, in green the buildings and in red is represented the area of the building if they ...
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48
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Clip Tool with PyQGIS give error
I've got the following Code for cutting points by a mask layer:
pointlayer = 'C:/temp/points.shp'
masklayer = 'C:/temp/mask.shp'
outputlayer = 'C:/temp/result.shp'
algo = 'native:clip'
params = {
'...
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How can I change individual sampling point colour based on the RGB values?
I have three sampling points (A, B, and C) with their respective latitude and longitude information. Additionally, I have three columns for each sampling point representing R, G and B values (the sum ...
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I am trying to run OTB segmentation and I am getting output polygons that are too big
I am running segmentation in QGIS Orfeo Toolbox on a MacBook pro. The first few times I ran segmentation, the results were satisfactory (the image was segmented with many small polygons). When I tried ...
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Generate a radius for a point, in order to count how many times a line passes through that radius
I am working on a project where I have to count the number of lines passing near a point. I plan to generate a radius around each point, since the lines do not cross the point, but pass close to it, ...
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40
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Removing relict lines on lidar DEM raster?
I'm relatively new to QGIS. I have a raster DEM with these odd lines for every cell, 5m resolution, is there a way I can smooth the DEM or another method to remove these lines using QGIS.
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Cannot call temporary layer while polygonizing a raster on PyQGIS
I been trying to call the resulting vector from the Raster Poligonization but it ends up telling me:
Unable to execute algorithm. Could not load source layer for INPUT:
*/OUTPUT.tif not found ...
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54
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Choose which outputs to open after batch processing in QGIS graphical modeller
I created a graphical model with many outputs. I need to test-run it many times to check the effect of some parameter choices on a single output. All other outputs would unnecessarily clutter my ...
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Speeding up QGIS Processing - Plugin [closed]
I am trying to calculate the angular integration and angular choice of a nationwide road network (Line SHP).
PST does the job, however it uses ALL (and by that I mean 100%) of my CPU's cores, but does ...
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79
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Join attributes from point layer to overlapping polygon layer in a one-to-one relationship in QGIS
I have a polygon layer and a point layer. I want to get the attributes from the point layer and join them to the polygon layer in a one-to-one relationship. This is normally easily done with the Join ...
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Gaussian in QGIS: SAGA vs Native Tool
I have been using SAGA Gaussian Filter to apply a filter to a raster layer, but for reasons I would like to use native QGIS tools if there is an equivalent.
There is a tool called Fuzzify raster (...
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