Questions tagged [qgis-processing]

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

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22 views

Save numpy array as raster in a Processing toolbox QGIS3

I am trying to convert an QGIS3 plugin to the Processing Toolbox in QGIS3 but I am getting stuck on how to save my processed numpy array back to a raster file in the end. How can I save the variable "...
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11 views

QGIS - Why are there multiple rows for each line of the line layer on which saga:crossprofiles is run via PyQGIS?

Intended result I have a layer that contains as features individual lines of varying lengths and seek to construct a layer that contains 100 equally-spaced elevation values over the length of the ...
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1answer
49 views

Running the processing algorithm 'selectbylocation' on only over selected rows of “intersect” layer

I can run the below processing algorithm myresult = processing.run("qgis:selectbylocation", { 'INPUT': selection_layer.name() , 'PREDICATE': 0, 'INTERSECT': ...
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25 views

Plotting percentage of classes of LULC map in concentric rings of 4 directions like below in a shapefile [closed]

LULC map showing concentric circles in 4 directional Zones.
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2answers
36 views

Pass temporary output between definitions / functions to use as input to next def

Lets say I have two functions: class AnalyseDTM(): def __init__(self): self.DTM = ('C:/Users/EH/QGis/Kvit_Tiny.tif') self.CreatePolygons() self.test() def ...
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1answer
34 views

Delete subselected features with PyQGIS and processing

In QGIS 3.10, I have layers in which I select features by location (to find duplicates), using : selected_features = processing.run('qgis:selectbylocation', {'INPUT':layer1, 'PREDICATE':0, 'INTERSECT'...
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0answers
28 views

QGIS crashes when deleting memory layer created by a script

I wrote some scripts that create shapes based on different sources (Excel, XML...). These scripts follow the template on Anita Graser's site and are integrated in my processing toolbox. They work ...
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23 views

How do I configure the “Processing R Provider”-Plugin in QGIS 3.10 on Linux Mint

I am using the "Processing R Provider"-Plugin in QGIS 3.10 running on Linux Mint 18. I have R installed, but QGIS is not able to find it: R is installed in "/user/bin": I have already tried to ...
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1answer
37 views

Automatic “Extract by Expression” processing with PyQGIS

Refering to this post and particulary the etrimaille's comment, I want to clean my dataset created from OSM data in QGIS. In each layer, I want to extract the entities having a specific key and value, ...
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34 views

QGIS processing tools - saving/exporting graph

I just tried QGIS processing tools for the first time. When using shortest path search for the first time, the algorithm is building a path graph (of course). However, the graph is never re-used. ...
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22 views

Why I can't process Landscape vector overlay of LecoS in QGIS?

I can't process Landscape vector overlay of LecoS in QGIS and I don't know why. I have the raster layer of a district that I derived from the supervised classification, and I have buffers of every ...
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1answer
30 views

Using GeographicLib's LocalCartesian to translate LiDAR (LAS format) data onto an SBET file in WGS84

I've been working for a while now to combine LAS 1.2 formatted LiDAR data with a matching SBET file to fill in the LASF_X/Y/Z fields in the LAS file. The matching of LiDAR points to SBET trajectory ...
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0answers
33 views

Automatic folder selection for processing algorithms in graphical modeller

Background I have 19 layers which ALWAYS have the same file name, but are located in varying folders. These layers are all inputs to several big models. Now, instead of defining each algorithm input ...
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0answers
21 views

Processing Modeller manual / use-case for Multiple Input and Model Variables

Is there a decent manual/examples available somewhere for the Processing Modeller? Official help is very barebones and doesn't explain the different inputs/model variables. Specifically I am ...
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0answers
17 views

QGIS Processing Modeller reusing output as input for next step

I would like to run the Sample Points algorithm over 20+ rasters, reusing the sampled result as the input for the next iteration of Sample Points. At the moment I am achieving the wanted result by ...
2
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2answers
38 views

Adding multiple fields in join attributes by location in graphical modeler

I want to add multiple fields in "fields to add" using the join attributes by location algorithm in the graphical modeler. It works if I add only one field, like DISTANCE, but when I want to add ...
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2answers
107 views

No processing toolbox in QGIS 3.10

I can't find the processing toolbox anywhere in QGIS3.10. I thought I just had to activate it but I can't find it under all plugins or installed plugins. Does anyone know where I can find it or how I ...
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0answers
24 views

Why vector tools cannot appear in QGIS data processing

Why vector tools cannot appear in QGIS data processing
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1answer
25 views

Image recognition between Improved vs Raw Land for city parcels from Aerial with QGIS? [duplicate]

Are there any tools or methods that allow QGIS analyze whether the lots/parcels have been untouched or developed, and return a "1" or "0" to a table or points layer or anything? I was thinking more ...
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0answers
23 views

QGIS TIN interpolation - error in pixel size of output

When using the "TIN Interpolation" tool in QGIS 3.10, the output raster file doesn't keep the pixel size I specify. For example if I specify a pixel size of 1.0m, the output file actually has a pixel ...
2
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1answer
68 views

Calling a plugin (quickosm) from a python standalone application?

I am trying to call the QGIS-plugin quickosm from a standalone Python application and I´m not quite sure how to or if this is even possible. My QGIS version is 3.10 (using OSGeo4W64) with the ...
4
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1answer
82 views

Transform Excel into vector in the Graphic Modeler

I have a graphic modeler with two inputs, a shapefile and an Excel file. I would like to make a join by attribute between the two. But I am confronted with a concern, the join can only do this between ...
0
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1answer
22 views

In QGIS processing modeller, how to use an input number in an expression?

I'm making a model where I need to use a certain years in a bunch of expressions. For example: ""era_2" > YEAR1" "era_2" > YEAR2 AND "era_2" < YEAR1 "era_2" >= YEAR3 AND "ERA_2" <= ...
3
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1answer
27 views

Generating urban blocks by road centerlines

I work on cartographic generalization project and I need to generate urban blocks by road centerlines.
5
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2answers
146 views

Definitive list of QGIS multiprocessing tools?

This question is not as straightforward as it seems, but can be summed up with the following: Is there a definitive list of geoprocessing tools for QGIS that currently support multithreaded ...
1
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1answer
54 views

QGIS Plugin Running in QGIS 3.10 but not in QGIS 3.4

I am new to QGIS, need your help in fixing one problem. I created a Plugin for QGIS. While creating it, I worked on QGIS 3.10 LTR version for which my plugin is working perfectly. Now when I shared ...
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0answers
32 views

Using qgis.core in anaconda environment

I am trying to use qgis.core in a Conda Environment with qgis, PyQGIS and Python 3.7 installed. I get over an over the next error: File "C:\Users\dg\.conda\envs\env_p3\Library\python\qgis\core\...
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0answers
35 views

Testing for Complete Spatial Randomness in QGIS

Is there a way (plugin/processing tool) to test a point pattern for complete spatial randomness (CSR) in QGIS?
4
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1answer
76 views

Exporting map layout from QGIS modeler

I am trying to write a processing script that takes a template file as input and writes out the current canvas content as a PDF. The processing script works fine. But when I use the script in a model, ...
2
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1answer
176 views

Open QGIS prococessing algorithm dialog with Python

I would like to programmatically show a processing algorithm dialog from Python. I gived a look to processing toolbox and I found that this is possible importing and instantiating the class ...
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0answers
17 views

Vector and Raster Analysis+conversions etc. not working

Pretty much all the analysis I'm trying to do in QGIS (3.4 Mac) is not proceeding. All the commands what I try to do in Processing tool box and GDAL are not working. Seems like I get all the time ...
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0answers
25 views

Repairing geometry using QGIS [duplicate]

I'm looking for a roughly equivalent tool in QGIS to the Repair Geometry Tool in ArcGIS Desktop. When I run some common vector processing tools in QGIS, I occasionally run into invalid geometry errors ...
1
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1answer
61 views

Stacking two vectors using QGIS [duplicate]

Although the coordinate systems in QGIS for 2 different vector layers are the same, there are differences between the boundaries. How can I superimpose this data? With the plugin or another way, I ...
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0answers
23 views

Processing plugin does not exist on Mac

I am having a difficult time figuring this out. I installed the QGIS 3.10 with the all-in-one package, and there was no error during installation. However, when I open QGIS, I don't see the ...
2
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0answers
67 views

Processing Toolbox from QGIS

I'm missing Processing toolbox in my QGis 3.4 (Mac-version). I know the feature can be activated when going to the Plugins and clicking it on. But it's not there. I've tried to solve this thing for ...
1
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0answers
36 views

QGIS API (PyQGIS) doesn't properly read layers

I have a problem with reading qgs file by PyQGIS lib. I'm creating python standalone stript which externally use PyQGIS from installed QGIS desktop application. The problem is that PyQGIS sometimes ...
2
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0answers
30 views

Combining graphic modeller Python output with another Python Script

I created a model that takes my point shapelayer, creates polygons from these points using minimum bounding geometry then adds a field named 'Zonekey' to attribute table; from qgis.core import ...
1
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2answers
41 views

Combine columns passed as parameters in QGIS graphical modeller

I would like to combine two fields in QGIS using graphical modeller. If I were to do it using field calculator, I would do it as follows: "field1" + ", " + "field2" Unfortunately, I cannot do it, as ...
2
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0answers
52 views

Calling processing algorithm in different file than main file for standalone application [closed]

I need to run a processing algorithm that is coded/called in different file than main file. I've read some posts (1, 2, 3, 4, 5) but they give a solution that runs algorithm in main file. When I use ...
2
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2answers
32 views

Densify and smooth out categorical raster with diagonal neighbors

I'm classifying vegetation types in QGIS (3.10). I have a pretty coarse raster that I want to smooth out. The standard approach seems to be to polygonize and then apply various smoothing algorithms (e....
2
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1answer
57 views

QGIS Processing Modeller - Select date by expression

I have a data file that contains current meter data for multiple days. I am trying to use the Processing Modeller to extract a single days worth of data for further manipulation, using the extract ...
2
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1answer
49 views

Incorrect Result Output Layer Name from Python Script

I have exported this code from Graphic Modeler of QGIS as a python script. The Model is outputting the final result as CN_Grid, as it should, but the script of the same model is giving results as ...
0
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1answer
50 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 ...
1
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1answer
53 views

How to compare polygons in different layers in QGIS 3.x?

To formulate my question with a concrete example: I have two multi-polygon layers of the same city. Layer A has polygons of the city divided in parts e.g. north, south, west, east. Layer B has ...
1
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1answer
25 views

QGIS 3.8 Batch Processing file path using Caclulate by Expression has square brackets between strings

I am trying to run a batch process using QGIS 3.8. I want to have the name of the output file use part of the name of the input file. For example the input file is "Landuse_A.tif" and the output is "...
3
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0answers
73 views

Processing script returns no layer

I am trying to run a processing script without a user defined layer output. The example below should create a vector layer with one point. The script runs without any error but the layertree is empty. ...
7
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4answers
395 views

No SAGA available in QGIS Processing

I am running QGIS 3.4.14 on Ubuntu Linux 18.02. I cannot see the SAGA tool in the QGIS Processing window. I can confirm that I have SAGA 7.3 installed and working as a stand-alone GUI application. I ...
2
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1answer
102 views

“Wrong or missing parameter value: Input layers”

I get this error message when I try p. ex. merge layers (native or SAGA algorithm) or package layers (processing) into geopackage. When I set files from a directory I don't have this problem. Am I ...
1
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1answer
57 views

SAGA difference tool in QGIS

I am using QGIS 3.4 Madeira. I want to use difference tool from SAGA from the processing tool box since my data has some invalid geometries and want to fix the issue later after using difference tool ...
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0answers
21 views

How to use OGR layer creation options for QGIS Processing algorithm outputs

When saving outputs from Processing algorithms, is it possible to use OGR's layer creation options à la ogr2ogr? In my case, I'm trying to save .geojson outputs from the Refactor Fields tool with the ...

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