Geographic Information Systems

Questions tagged [qgis-processing]

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Spatial data processing framework that brings advanced analysis capabilities to QGIS.

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37 views

How to enable Python scripts in processing toolbox in QGIS 3.16

I'm not able to enable Python scripts in the processing toolbox. It should turn up in the toolbox (see the third screenshot). The Python logo is also missing from the toolbox. Is there something wrong ...
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2answers
29 views

QGIS v/s MapInfo - Differences in Distance Measurements

Distance calculated in different software (MapInfo and QGIS) has given me differences in distance values. To be more precise, it's mostly happening when the distance is more than 25 miles. I doubt ...
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Passing list as reclassify input table parameter in qgis.reclassifybytable algorithm

Following up on Save and load the classes definition table in the QGIS reclassify by table tool, I decided to run the qgis.reclassifybytable algorithm using PyQGIS to reclassify an aspect raster. Here'...
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32 views

Two Separate QGIS Plugins Under one Provider

I have developed a QGIS processing plugin that has a processing provider of its own. That plugin is working fine. Now I am developing a second plugin and I want to provide it the same provider so that ...
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1answer
45 views

Running QGIS Processing Algorithms in Standalone Python Script in Windows

I want to run this code outside qgis as a standalone python script. import processing, os os.chdir('C:/Users/User/test/25') alg_params = { '-c' : False, '-f' : False, '-i' : False, '-n' : False, '...
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1answer
9 views

Export Data From Merged File to Individual

I Have a merged shape file with 'n' number of cities in it. Exporting them by selecting their names individually is a difficult thing and wasting my time. Is their any query in QGIS to export Data ...
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37 views

Removing number of special characters at same time using QGIS [duplicate]

I have a file with number of special characters in it. I can easily replace that in ArcGIS by building a query. How can I replace them at the same time in QGIS?
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2answers
27 views

Deleting data by location using another shapefile

I have two shapefiles: one is main file and another is a part divided (manually by selecting) from the main file. Now i want to delete the divided part from the main file with the help of divided part....
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25 views

Running QGIS 3.1 Graphical Modeler Script as standalone

I have troubles running a Graphical Modeler Script as standalone via the OSGeo4W Shell console. Everything works fine when I run the script in QGIS. When I open it via shell, nothing happens. I think ...
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49 views

Drawing a line with the same length as the layer extent in QGIS Modeler

How can I use the height of a polygon (layer extent) to construct a line slightly longer than the polygon? I’m in the Modeler and my input is s polygon layer. I will be constructing the line from a ...
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33 views

Constructing point at corner of layer extent using QGIS Modeler

I’m in the Modeler. My input is a polygon layer with a polygon (agricultural field) and a line layer with a line indicating a direction of travel within the field. The field will be filled with ...
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1answer
34 views

How to create polygon automatically with coordinates [duplicate]

I have some bunch of points in an area and I want to draw connecting lines with the help of points to create a closed polygon. But all these needs manual efforts. Can any one explain to me how to ...
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19 views

“Argument list too long” error while converting shapefile to NetCDF

I'm trying to convert a point shapefile to a NetCDF (.nc) file with QGIS using the tool Rasterize (vector to raster), but I keep getting error. Below is the log from one of my trials. QGIS version: 3....
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1answer
52 views

QGIS Processing algorithm output

I am developing a plugin in QGIS using Python language. This plugin uses algorithms from Processing Toolbox and I save some results in the temporary folder assigning QgsProcessing.TEMPORARY_OUTPUT in ...
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2answers
110 views

Count number of features in a geopackage and write to a file

I'm tasked to create a simple catalogue of 2000+ geopackages, and hope there is a way to do that with QGIS. The idea is to batch run over all these geopackages and write the following to a CSV file; ...
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3answers
227 views

Adding scripts to Processing toolbox via PyQGIS

Is there a way for adding new Processing scripts into Processing toolbox using PyQGIS? In the GUI, I can click on "Add script to toolbox", but I want to add scripts using PyQGIS. QGIS ...
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0answers
56 views

Different layer.name() in batchmode in QGIS processing script

Different layer.name() in single layer processing and batchmode in QGIS scripts. QGIS version 3.10.7. My example script: # -*- coding: utf-8 -*- """ ***********************************...
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2answers
124 views

Get folder path to QGIS processing scripts from PyQGIS

Where is stored path to processing scripts folder in PyQGIS? Version of QGIS is 3.16. I want to get this path by Python script. I suppose then, is stored in processing object: from qgis import ...
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41 views

Nearest unique duplicate points

How can I highlight nearest(certain distance) unique duplicates? Actually I tried a process in ArcGIS but only duplicates are pulled out from the entire file without considering distance. How can I do ...
5
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2answers
69 views

Extraction of line segments in front of the street

I have a layer of lines that represents a layer of plots. I want to eliminate all the inner segments to have only the segments that go out into the street. Thus, I want to determine the sum of the ...
4
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1answer
41 views

QGIS Processing modeler not showing toolbar

I've just installed QGIS recently (3.10.10 with GRASS 7.8.3) on a new computer. Previously, I used the same version and there's a toolbar in the Processing Modeler (to save and run model). But now, I ...
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3answers
200 views

Allocating point attributes as default values for line layer

I want to add points "ID" attribute as a default value for a line created between two points, for line layer fields "start_point" and "stop_point".
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3answers
118 views

Eliminating duplicates only if data is the same according to attributes

Having duplications in the data is quite natural and removing them is quite hard if we didn't have the same attributes. In QGIS there are tools to eliminate the duplications but only if the data is ...
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1answer
2k views

'reportError' in subclass of QgsProcessingFeedback never running

I have two layers, layer_a and layer_b. Both have invalid geometries. When I run a processing tool, it throws an error as expected. Based on the answer posted here by @ndawson, if you subclass ...
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1answer
39 views

Returning error text from QgsProcessingFeedback

I have a snippet that intersects two map layers (blockLayer and ogLayer) in QGIS; and prints out when a bad geometry prevents the intersection from occurring. It builds a subclass from ...
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0answers
47 views

Changing the Processing plugin icon - QGIS

I have built a processing plugin which shows up in the QGIS Processing Toolbox. However, I am struggling trying to change the icon. Usually I do: pyrcc5 -o resources.py resources.qrc and it updates ...
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1answer
82 views

Capture coordinates of a rectangle drawn on the canvas

I am writing a process that will take parameters as input, and then process part of a raster layer. One (well, four) of the parameters should specify a rectangle on the canvas. Ideally the user should ...
4
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1answer
43 views

Listing the raster layers on the canvas for selection by user

I am creating a processing script that will take input from the user. The input parameter is to be a raster layer. Using the method described at https://www.qgistutorials.com/en/docs/3/...
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1answer
58 views

Is it possible to get the the layer returned by a GRASS tool without saving it to disk in QGIS?

I use some GRASS tools in QGIS Python Console. All tools I use return a dictionary with a key and a value which contains string path, like this: {"output": "file/path"}. There is ...
2
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1answer
90 views

Convert scripts for processing toolbox

Does anyone know how I can turn this console script into a script that I can integrate into the processing toolbox? I tried a few options, but I don't do very well in python, and I always get stuck. # ...
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0answers
37 views

Output of Processing Algorithm Doesn't Show Up in Layers Panel

I'm writing a PyQGIS Processing plugin that takes a series of inputs and uses them to run other PyQGIS processing plugins that I wrote. The problem I'm having is that the layers my plugin returns don'...
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12 views

QGIS r.water.outlet multiple points processing modeler

I am trying to create a process with the process modeler. I want to run r.water.outlet by importing multiple points (a shapefile of points). I searched through the internet and StackExchange. Could ...
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2answers
72 views

QGIS: Create line vector between line without drawing

I have transected the Transect line(white line) from a densified pink line Now I want to draw the green line between my transected line. Instead of doing it manually, is there another way to do it by ...
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0answers
42 views

Create non trivial join/view via PyQGIS in a QgsProcessingAlgorithm

In the context of QgsProcessingAlgorithm, what is the best way to take information from several layers and output based upon that combination of layers? or: What is wrong with my layer creation? The ...
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0answers
30 views

How to characterize polygons that are created when you join 2 vector layers?

I am using QGIS for the first time. I have a map of an aquifer with 2 different vector layers that split the aquifer differently into several polygons. In the first layer, I used some points(measuring ...
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2answers
40 views

Converting XY Coordinates to Projected Local Coordinate System using QGIS

I am working in QGIS 3.14, and I have created a shapefile with X and Y coordinates that has COVID testing centers in Maryland and the EPSG is 4386. I want to do a buffer algorithm on these sites to ...
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2answers
89 views

Showing dialog box even though QGIS is freezing

I have a long script in PyQGIS that contains three processing tasks after another. I want to display a pop up box (like "QProgressDialog"-Box) for each task when it is finished. Example: ...
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0answers
65 views

Specifying dependable layer names in QGIS Processing Modeller [closed]

I am creating a model in QGIS (3.10.3) Processing Modeller (Win 10[64]). Final Objective To create Voronoi polygons from centroids that are clipped to a higher, polygon, geometry. Hurdle The Voronoi ...
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14 views

Execute the command r.thin

I have an image that I want to thin, after calling the image on the grass and executing the r.thin command, it was not thinned and the output image is as follows: image original: And output image of ...
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3answers
213 views

Find nearest line feature from point in QGIS

I have a line feature set and point feature set. I want to get the nearest line feature from every point. For this, the line features are converted to point using "Extract Nodes" tool. Then ...
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1answer
40 views

QGIS 3.14: Remove intersect points on a line

Is there a way to remove the point that intersect with the red line instead of removing it manually? I tried using geometry checker
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1answer
43 views

Creating an oblique Mercator projection using proj and QGIS

I am trying to create a coordinate system within QGIS that's aligned with a great circle between two points. The points defining the great circle are (-44.0597,168.7192) and (-42.7365,171.4428) and, ...
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1answer
35 views

rscript in QGIS processing toolbox and Rstudio, results mismatch

I am using my own R scripts in QGIS. Before adapting them to work in QGIS, I write them in RStudio to make sure they work properly. I then use different scripts in a batch model. In RStudio I have ...
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1answer
80 views

Routing with several stops using QGIS

I have point layer and a network (segments) stored in a geopackage and using QGIS. The number of points and their ids are always different. What I need is to get a route from first to last points but ...
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1answer
31 views

QGIS: Error code showed up after Landsat 8 TOA and crashed the program (SCP plugin)

Trying to get all bands corrected but it failed every single time in version 3.10 or 3.16. Error codes showed as below:
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1answer
31 views

Batch Cutting a Raster File using a Moving Extent in QGIS

I have a LIDAR file with 20 GB size, and I would like to cut it into smaller areas for gravity terrain correction. It is more like a moving window processing, with LIDAR as the windowed data, then the ...
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0answers
24 views

Return Output of PyQGIS Processing Plugin as Output for Other Plugin (QGIS 3.14)

I'm trying to chain together several PyQGIS Processing plugins I've written into one super-plugin. I'm aware that I can do this with the Visual Modeler but a. our team is trying to make a quick user-...
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0answers
59 views

Set project variable to a field value when iterating over vector features with graphical modeler in QGIS 3

I have a Data layer containing features with some fields (e.g. rows with color and name). In the Graphical Modeler I want to iterate over the features and assign the field values to some project ...
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0answers
36 views

How to link SQL file with relative path in Processing Scripts

I wrote a processing tool, which exports some tables from PostGIS to package, and as part of the export, I am calling an external SQL file to add some triggers, etc. The SQL file is located as my ...
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0answers
27 views

QGIS3.x using processing algorithms outside of python console (when writing a plugin)

For a school assignment I need to write a QGIS plugin. Part of the plugin that i'm writing needs to use the 'select by location' processing tool on a previously created buffer. The codelines that I ...

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