Questions tagged [qgis-processing]
Spatial data processing framework that brings advanced analysis capabilities to QGIS.
1,174
questions
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1answer
25 views
Store the filenames of .kml files into the attribute table of a shapefile
I have to be joining .kml files in a single shapefile. The problem is that the kml files comes with a name that when I convert it into a shapefile it is not kept in the attribute table. thus, I lose a ...
1
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0answers
14 views
Output layers order in QGIS Graphic Modeller (algorithm execution order / dependencies)
I created a simple model in QGIS graphic modeller that takes in input parameters like drive time ranges and start location and outputs 3 styled layers including "start_point", "...
0
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0answers
34 views
Use core code of QGIS in my own Python scripts
I would like to know if I can use the code of the default functions that come in QGIS, for example the Intersection function.
When you click on the help button it redirects you to the user guide where ...
3
votes
1answer
33 views
How to Group Parameters in PyQGIS Processing Plugin
The PyQGIS Processing Plugin I'm writing has a lot of parameters, most of which are advanced and won't be necessary for most users. I'm concerned that a user will be confused if they see all these ...
0
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1answer
31 views
Splitting feature into layers which are overlapped in same layer in QGIS
My script needs to select each feature in layer. While selecting features I found some of feature are overlapped. Feature can be selected but cannot highlight in map canvas.
Is there any plugin or ...
1
vote
1answer
20 views
r.terraflow fails after using fill-sinks
I'm using QGIS 3.10.11 with GRASS 7.8.4, and the default SAGA version that's included with the QGIS standalone 3.10.11 installer from QGIS.com.
I'm having an issue where r.terraflow fails after using ...
3
votes
2answers
82 views
Select polygons containing particular attributes from points layer
I have thousands of polygons (buffers) in a single layer and I have a points layer containing tree species. The tree species points shapefile has an attribute called Tree_Type. I need to select only ...
0
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1answer
33 views
Finding spatial difference between two vector layers with multiple features in each layer using QGIS
I am learning on the job with QGIS.
I have two state level vector layers with individual shapes for each county inside the state boundary. I am trying to identify the area differences between each ...
-1
votes
1answer
38 views
Detect yellow spots on an image [closed]
I have a big raster image (12 GB) and I would like to detect yellow stains on it. I did try the Zonal Statistics but it is almost impossible to find the right parameters in order to detect the stain. ...
1
vote
2answers
90 views
QGIS Processing Plugin Generating Features with Attributes
I'm writing a QGIS processing plugin that creates a point feature layer. I'm able to add points to the feature layer just fine but the attributes I add don't show up in the Attribute Table after I run ...
0
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0answers
39 views
QGIS: Running field calculator from Python. Adding new calculated field
I would like to add a new field to a layer, creating a new memorylayer from the existing layer. Where I create a new field using the expressions that are available to the "Field calculator" ...
2
votes
1answer
51 views
Polygonize area surrounded by buffer in QGIS
I have an automated system in QGIS that separates loops from GPX traces and works out their centroid using 'Polygonize' >> 'Keep N biggest parts' >> 'Centroids'.
However, quite often it ...
0
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0answers
14 views
Running QGIS processing tools in the OSGEO4W shell using the qgis_process functionality, syntax errors
I am trying to run QGIS processing tools in the OSGEO4W shell using the qgis_process functionality. I believe this functionality is fairly new as I have been having a hard time finding documentation ...
1
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0answers
27 views
Using various script forms in Linux QGIS 3.12
In the last few weeks, I have noticed that various script forms in QGIS (3.12, Linux Mint 19.3) have strange cursor behaviour. Spaces in scripts are unevenly represented on the screen. This is hard to ...
1
vote
1answer
29 views
Add X/Y coordinate format incompatible with viewshed tool coordinate format in QGIS
I am performing an r.viewshed analysis (id: grass7:r.viewshed) in QGIS 3.10.9 with Grass 7.8.3.
My question pertains to the 'coordinates' parameter. When I use the r.viewshed tool in QGIS and select a ...
3
votes
1answer
43 views
Which buildings have access to nature where more than 50% of the nature area is closer than 3km?
I have 1) a file with all the residential buildings in a small municipality and 2) a file with all the surrounding green areas.
I'm having a hard time solving this because the residential buildings ...
1
vote
1answer
25 views
Is there a simple table structure update procedure for a manipulated PostGIS layer under QGIS
I have an intensive data exploring session using Postgresql/PostGIS as a backend and try to explore the results using QGIS. Within QGIS I have a defined a "complex" style to show the results....
1
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0answers
16 views
QgsProcessingException: There were errors executing the algorithm
I have been trying to run the nearest distance to hub points process (https://docs.qgis.org/testing/en/docs/user_manual/processing_algs/qgis/vectoranalysis.html#qgisdistancetonearesthubpoints) in ...
1
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1answer
33 views
Customize QgsProcessing output layer name
I' writing an own QgsProcessing Algorithm and I want to give the output layer in the registry a custom name instead of the default "Output layer". I want to do that during processAlgorithm(),...
0
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1answer
28 views
PyQGIS algorithm qgis:joinattributesbynearest not found
After re-installing Windows and QGIS 3.14 it seems like some PyQGIS algorithms are not working. For example:
processing.run("qgis:joinattributesbynearest", options)
gives
core....
1
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0answers
26 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 ...
0
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0answers
27 views
PyQGIS chaining consecutive processing algorithms timing Issue
I am trying to run the merge vector layers algorithm for multiple shapefiles. Then run the join attributes by location between a merged polygon shapefile and merged multiline shapefile. All files are ...
1
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0answers
21 views
Exported QGIS model does not work: Invalid input error
This question is linked to this one:
QGIS Graphic modeler: Loading in all the layers
I have a very complex model which converts a specific file (pmkl.json) which is a feature collection of points ...
0
votes
2answers
53 views
Creating Network Flow Diagram using QGIS
I have a Telecom cable network in Geopackage format.
How do I create a Network flow diagram from which to represent the relationship between Fiber distribution hub to Network access point?
0
votes
1answer
43 views
QGIS Graphic modeler: Loading in all the layers
Currently I have special script/model, where I convert a geoJSON feature collection to some seperate shapefiles.
There was small pre step and prerequisite, that I want to eliminate, normally we load ...
1
vote
0answers
15 views
Scatter plot in Process Algorithm
I am trying to plot a scatter plot in the Process Algorithm on a data frame to show the relation between custom data and used under the K-means algorithm. But every time I try to run it. QGIS gets ...
0
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0answers
31 views
Editing processing toolbox algorithm “Vector Layer Histogram” output
I have a vector/shapefile layer with around 1500+ individual symbols. Each symbol has an attribute 'EVIMean' that I need to use for a histogram and it is a numeric value.
I first tried the default ...
0
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0answers
37 views
QGIS - graphical modeler aka. processing toolbox - update only selected fields
I have two layers:
point layer representing some house addresses.
polygon layer representing some kind of territory.
What I'm trying to do is, create a model where I select the points inside the ...
0
votes
0answers
18 views
QGIS Layout/Print Composer: Automatic table refresh upon creation from template
This Question is related to this one:
QGIS print layout: Pulling the name of the map theme from table
Currently I have two specific templates I use for A3 and A0 plans both of them are structured the ...
0
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0answers
31 views
Using QGIS Processing-Toolbox in stand alone Python scipt (Microsoft Visual Studio)
I'm using QGIS 3.14, Python 3.7, Processing-Version 2.12.99 and Microsoft Visual Studio 2019 (IDE).
Everything works fine, the only problem I have is the import of the processing-algorithms. Related ...
2
votes
0answers
21 views
Tools for fixing geometry of shapefiles
does someone have experience in fixing geometry errors in QGIS 3.10 LTR? I'd like to fix geometries first and then use processing algorithm "Snap geometries to layer". So far, the algorithm ...
0
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0answers
27 views
What is the best way to break up a shapefile into discretely sized tiles?
TL;DR version: I need to break up road vectors in QGIS to 4,033km2 tiles to import into an UnrealEngine landscape.
I am evaluating a plugin the imports GIS data into UnrealEngine for a simulation. ...
1
vote
1answer
25 views
Using NNJoin-Plugin through Python console
I want to write a Python script which I can execute from within QGIS 2.18 (from the Python console).
The Python script should calculate the nearest line (out of a set of lines) of a given point (out ...
0
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0answers
27 views
Fill nodata holes in discrete integer raster with majority value of adjacent pixels QGIS
I have a large land cover raster with classified integer values from 2-22. There are some single or double pixel no-data gaps where I merged 2 adjacent tifs together. If this were a continuous raster ...
0
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0answers
30 views
Processing toolbox won't open tools
Since yesterday the processing toolbox of QGIS 3.10.9 AND 3.14.15 won't open any tools. Originally, I wanted to use the select by location tool, but after trying no tool at all will open. It doesn't ...
0
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0answers
17 views
Error code using 'Proximity (raster distance)' tool
I have been trying to use this function following 2 teaching methods and get the same problem.
I am trying to create a Boolean Raster layer from a previous Boolean Raster layer. The first boolean ...
0
votes
2answers
36 views
Access attribute names and add new attributes in processAlgorithm
How can I access the layer attribute names of the selected layer?
I have tried checking on Google but all the methods are mostly for the previous version and I am using py3 version.
att = source....
1
vote
0answers
15 views
Autofill field parameter based on parent layer in Processing Provider
I'm building a custom Processing Provider and would like my field dropbox to be dynamically filled with the first valid field of the associated parent layer. Currently, the dropbox list is updated if ...
0
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0answers
21 views
Integration R in QGis 2.18 in Ubuntu
I work in Qgis 2.18.17. I try to install "Processing R Provide" as it shows in video
https://www.youtube.com/watch?v=nEJJE4DRiPQ&t=193s
but as I understood it is usefull only for windows ...
0
votes
0answers
40 views
Accessing input layer when using “Selected features only” returns 'NoneType' object in QGIS 3 processing script
I am trying to write a processing script in QGIS 3.10.8 which would execute database function based on the selected features (or their id). I defined the input in a way that it accepts a point vector ...
1
vote
1answer
56 views
Save CSV with separator using PyQGIS 3?
I need save selected attributes of layer as CSV with separator. This is my code:
def initAlgorithm(self, config=None):
self.addParameter(QgsProcessingParameterVectorLayer('Input', 'Input', ...
0
votes
0answers
20 views
How to “merge” multiple raster ASTER L1T bands?
I want to generate a Land Surface Temperature map using ASTER products. I used the Semi-Automatic Classification plugin and followed this tutorial. However my study area is too large and required at ...
0
votes
0answers
24 views
How to run an exported QGIS program as a stand-alone application?
I have a research partner who exported their QGIS algorithm to a python script, and my job is to use that Python file to create a web application that provides access to that algorithm.
My eventual ...
3
votes
2answers
92 views
How to insert missing vertex of two geometry overlaps area in QGIS
I need to add the missing vertex of two lines intersection places using QGIS.If any default plugins or tools available for fixing missing vertex in qgis,kindly suggest me.
My Inputs:
In above ...
1
vote
0answers
25 views
Adding multiple vector files in a folder as an input in QGIS processing modeler using iterator tool
I have shapefiles in a folder that I intend to use as an input in QGIS Processing Modeler. I would like to iterate within the folder to add each of the shapefiles as an input. It did it in ArcGIS ...
0
votes
1answer
59 views
Letting user select multiple fields from input layer for field calculator using QGIS Python Script
I am trying to build a script (python 3) where a user can select a number of numeric fields, define a set of numbers, and the script will create a new field after multiplying the field with the ...
1
vote
2answers
334 views
Errno 13 “Permission Denied” when running tools and plugins on QGIS
I am having an issue with multiple tools when using QGIS where I am constantly getting PermissionError: [Errno 13] Permission denied type errors.
A lot of it seems to be associated with tools that use ...
0
votes
0answers
14 views
Interface customization in QGIS — I am unable to switch off the layer styling options of the layers
I tried to switch off the layer styling using interface customization option but it is still visible in the layers tab. How to we restrict the styling as the project file will be used by many users .
0
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0answers
37 views
QGIS 3.10 - Field calculator expression running in Attribute Table and not in Processing Modeler
I use the Field Calculator in the Attributes table and run the operation : "FieldA" - "FieldB", where "FieldA" and "FieldB" are height distances in meter with a ...
2
votes
1answer
57 views
Create Point based on location of minimum elevation inside a polygon in QGIS3
For QGIS3.0:
Using DEMs, I am drawing polygons around depressions. Inside that polygon, I need to generate not only the minimum elevation value but the location that value was extracted from; this ...
