Questions tagged [qgis-processing]
Spatial data processing framework that brings advanced analysis capabilities to QGIS.
1,038
questions
1
vote
1answer
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 ...
0
votes
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 ...
0
votes
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
vote
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 ...
1
vote
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
votes
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 ...
1
vote
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 ...
1
vote
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
votes
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 ...
1
vote
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 ...
1
vote
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
votes
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
votes
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
votes
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
votes
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
vote
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
vote
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 "...
1
vote
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. ...
5
votes
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
votes
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
vote
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 ...
0
votes
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
votes
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
votes
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
votes
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
votes
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
votes
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
votes
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 ...
1
vote
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
votes
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,'...
1
vote
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
vote
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 ...
0
votes
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
votes
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
vote
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
votes
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
votes
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
votes
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
votes
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
votes
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 ...
1
vote
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
votes
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
vote
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
votes
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
vote
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
votes
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
vote
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
vote
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
votes
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 ...
