Questions tagged [qgis-processing]

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

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53 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
16 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
21 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
52 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
20 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
46 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 ...
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0answers
30 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 ...
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0answers
33 views

Using Input Layer as part of Global Expression in PyQGIS

In Advanced Python Field Calculator tool, I can get a feature's geometry using $geom or its id using $id in Formula section. Is there a way to get reference of layer selected as Input Layer to use in ...
2
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0answers
21 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 ...
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2answers
35 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 ...
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0answers
46 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
27 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
42 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
41 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
41 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
50 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
21 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 "...
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0answers
63 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. ...
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3answers
211 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
62 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
51 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
16 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 ...
2
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1answer
52 views

Distance matrix returns points in wrong order QGIS 3.4

I'm using QGIS 3.4 on Windows 10 and scripting in pyqgis. I have a layer representing building centroids that is in a projected CRS. I want to find the azimuth between each building and its nearest ...
2
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2answers
53 views

Tool for making sure two vector layers are identical?

I have to constantly compare new project boundaries with old project boundaries (both are polygon shapefiles) to make sure that both the outside boundaries and the inside segments haven’t changed. Is ...
2
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2answers
147 views

Converting selected polygons to lines in QGIS modeler

I have a vector file which I would like to add using "add Vector Layer" (the vector file is a polygon). I would like to convert the polygon file to lines, however only selected polygons. I had an ...
6
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1answer
118 views

Change encoding type for all files or whole project

How can we change encoding mode for the whole project rather than doing to single shapefiles in QGIS 3.4? I wanted to change "UTF-8" to "Shift_JIS" to all project vector files.
2
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0answers
39 views

QGIS 3 Processing tools don't seem to work (can't load output)

I've got a new machine running on Win10 (I was previously on Win7) and I can no longer use... pretty much any algorithm, especially from SAGA. It's probably something to do with environment variables,...
3
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1answer
61 views

How can I process vector difference between 1 group layer and 1 polygon layer?

I have one layer group called 'left_buffer', containing 40 buffered polygon layers (name: 1,2,3,...,39,40). I want to use difference vector tool between 'left_buffer' and 'bldg' layer, but I'm getting ...
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0answers
28 views

Distance nearest hub with conditions

I have 3 shapefile: pipes (line), junctions (point), customers (point). I want to bring customer demand value from customer to junctions with conditions: First condition: Nearest road Second ...
3
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1answer
42 views

Export looped layers at once using PyQGIS?

I am trying to use one-side buffer on road centerline (layer name: small_road) by 1~40m. I've succeeded in creating one buffer (2m) file at a time using 'SEGMENTS':2,'JOIN_STYLE':0,'MITER_LIMIT':2,'...
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0answers
39 views

Unable to Determine Error in QGIS Log Message Panel

A plugin is built for our road data network in qgis which basically splits roads at intersection and use grass v.clean algorithm, this tool runs smoothly until now, but now it's not splitting road, ...
1
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0answers
54 views

PyQGIS grass7:v.distance parameter error “The number of columns and the number of upload parameters should be equal!”

I am currently working on a Python script for QGIS in which I would like to obtain the (minimum) distance from each point (polygon centroid) in the points layer centroid_layer to the line layer ...
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0answers
48 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 ...
2
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0answers
17 views

Outputting layer as table at end of process

I am in the process of migrating some QGIS 2.x processing toolbox script to QGIS 3.x. I have a collection of scripts that helps in the seismic 3D planning and geometry processing. One of the scripts ...
1
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1answer
48 views

Using memory layer as input with processing runalg? (QGIS 3)

My first processing runalg creates a memory layer as output. I need to use this layer as the input for second runalg. #first processing.run("qgis:fieldcalculator", {'INPUT':'...
2
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0answers
12 views

Sharing classes and methods code among processing scripts

I am writing a set of processing scripts for seismic data acquisition (2D and 3D) planning and geometry processing. They are very crude scripts (I'm not a developer) that performs the tasks I meant ...
3
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0answers
56 views

Selecting and deselecting features with PyQGIS

I'm trying to apply the algorithms "Random Points along Lines" at the feature level. I did some PyQGIS code to iterate through the features to select each individual instance and apply the algorithm ...
4
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1answer
130 views

Processing toolbox not working in QGIS 3.4.13

The processing toolbox stopped working in the previous QGIS 3 ltr version I had installed. Now installed 3.4.13 but processing toolbox still not working. I've tried changing the GRASS path without ...
2
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0answers
34 views

Feature selection

I have several data points for which, whenever I activate the select feature button and complete the marking out of the points I need, the mark outs vanish. In other words, the points are not selected ...
4
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1answer
54 views

How to edit a processing tool in QGIS

Is it possible to make a copy of a tool from the Processing Toolbox in QGIS and make edits to it? As an example, I would like to make a copy of the Import geotagged photos tool and then edit the code ...
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0answers
18 views

Processing: Using attribute as input for algorithm

In Processing Modeller, is it possible to pass a field value (attribute of a feature) to a file name? Example: I have raster, MyRaster.tif, and I would like to clip it by different polygons inside ...
2
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0answers
38 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 ...
2
votes
1answer
38 views

QGIS polygonize issue: GDAL DLL load failed

I am using QGIS Desktop 3.10.0 and I have some issues with the polygonize tool. When I run the polygonize tool, a warning shows up saying that there is an “Import Error: DLL load failed” (see Figure 2)...
1
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1answer
79 views

QGIS Unable To Load Processing, Vector Tools and Plugins

I am currently facing an issue with QGIS 3.8.3. In which I am unable to use Vector Tools and other plugins. Below are some of the trackbacks for the Python error. I am unable to show all due to the ...
2
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0answers
101 views

QGIS Python AttributeError: 'NoneType' object has no attribute 'processingRegistry' [closed]

I am executing a QGIS Desktop 3.8.3 Python 3 script. from osgeo import ogr, gdal from gdalconst import * from qgis.core import * import qgis.utils, sys from qgis.gui import * from PyQt5.QtGui ...
1
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1answer
27 views

QGIS - Translation problems

I've enabled Processing plugin and provided compiled i8n file but somehow there is a error which causes GUI to create two separate buttons. One of them is translated and one is not. Does anybody know ...
4
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1answer
70 views

Failure importing CSV file lines

I'm trying to import a CSV file in QGIS 3.4 using the common method of "Add Layer" > "Add Delimited Text Layer". But QGIS is reading every row of the dataset as a column title, and nothing is in a row ...
1
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1answer
51 views

Display labels set from within QgsProcessingAlgorithm in QGIS 3.x?

I'm writing a simple QgsProcessingAlgorithm and I need to set some labels (to display the azimuths of the sides of a polygon). I can set the labeling expression alright (the expression is properly set ...
1
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0answers
47 views

processing.runalg('qgis:splitvectorlayer') --> wrong Output directory

I'm tryiing to split a vector layer using this code : processing.runalg('qgis:splitvectorlayer', 'D:/Images_Sentinel_2/2A/shp_taitt/contour.shp', 'nom', 'D:/Images_Sentinel_2/2A/shp_taitt_split') ...
2
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0answers
34 views

QGIS 3 script new style more parameters

Since QGIS 3.6 there has been introduced a new script style. I am fairly new to this scripting and I would like to ask for the code to do an fix of two layers and after this to make an intersect of ...