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Questions tagged [qgis-processing]

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

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14 views

How to Host QGIS Plugin

I want to host QGIS plugin such that anyone with the host link could be able to upload his data and see the output on QGIS desktop in the web browser. I tried to search on the internet, all I could ...
3
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0answers
22 views

QGIS 3 - Save processing output to memory and turn into numpy array?

I'm currently developing a python plugin for QGIS 3. In short, the code conducts among others a viewshed algorithm, turns the output in a numpy array and calculates some spatial metrics the user can ...
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0answers
15 views

Clipping outside QGIS with PyQGIS?

This is my first script and I having a problem trying to clip a shp file. I'm running on a linux server and this is my code: #! python from datetime import date from qgis.core import * from PyQt4....
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10 views

“Cannot find variable: staticmethod” message while running Processing script

Every time I run my own processing script in QGIS 2.18.22 I get this message fifteen times in Processing tab in Log Messages Panel : 1 Cannot find variable: staticmethod 1 Cannot find variable: ...
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1answer
29 views

Get R scripts from on-line scripts collection

I have QGIS 2.18 installed on Win 10, I tried to add online R scripts from processing toolbox, but i get errors. "Python error: An error has occurred while executing Python code: See message log (...
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0answers
37 views

Using Union tool in QGIS?

Here is my scenario: I am trying to use Union to combine the land and mangrove shapefiles in QGIS and to compute for the areas of each individual geometry. What I did: First, I cleaned them. Upon ...
6
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3answers
113 views

Programmatically changing line lengths in QGIS?

Provided a set of lines with various lengths, I would like to change their lengths (hence, changing their geometry) to a specific value, using their centroid as base point. I have checked the ...
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0answers
16 views

QGIS 3 processing script won't show gui when executed from editor

Different from QGIS 2, when I execute a processing script from the Processing Script Editor by pressing the Play-button in QGIS 3 it's GUI is not created. Seems to me that the initAlgorithm() method ...
3
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1answer
53 views

Update processing scripts in QGIS 3

When I edit a processing script (QGIS 3.2) with right click > Edit script... in the processing toolbox, save it and then try to execute it by double clicking it in the processing toolbox, the version ...
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1answer
44 views

PyQGIS scripts outside of QGIS GUI running processing algorithms from GRASS provider

I'm writing a script that I would like to work outside of QGIS GUI. The script uses the processing algorithm standalone just fine for the native algorithms, however I am experiencing errors when ...
1
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1answer
38 views

Access string output of QGIS 3 processing script in graphical modeler

In the good ould days of QGIS 2 I created a processing script, that takes as input a table and a table field (table has only one record) and returns the string attribute value of the table field: ##...
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0answers
19 views

Converting QGIS Processing Modeler Python (.py) file to (.svg)

A Processing Modeler can be saved in QGIS 2.18.15 as a Python (.py) file. Adhering to good advice by @Spacedman in an earlier thread, I wish to know what are the many ways the (.py) files for the QGIS ...
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0answers
18 views

Backwards compatibility for QGIS 3.2.1 Processing Modeler [duplicate]

I have created multiple models using the Processing Modeler in QGIS 2.18.15. However, I could not open these .model files in the user interface for the Graphical/Processing Modeler in QGIS 3.2.1, ...
5
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1answer
60 views

Do I need to have QGIS installed on a machine to make use of it's python libraries?

I'm trying to make a simple stand-alone app to expedite the production of some site plan maps for my work. The maps are very formulaic, and follow a set template every time. With the QGIS libraries, I ...
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0answers
44 views

Embedding QGIS Python Script in C++(Qt Creator)

Is there any way that I can embed and use QGIS Processing algorithm written in python on Qt Creator using C++. If so how can I share the layer and other instances created in C++ with the embedded ...
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1answer
50 views

QGIS Python troubles with 'processing'

I have made a script for multiple clipping raster images with a shapefile as follow: ##Clip Multiple Rasters with Vector=name ##Utilities=group ##RASTERS=multiple raster ##VECTOR=vector ##OUTPUT=...
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0answers
21 views

Missing toolbar and panel from graphical modeler in QGIS

Does anyone know how I can turn on the toolbars and panels of the QGIS 3 graphic modeler? I closed them and now I do not know how to enable them again, consequently only a blank window appears. I'm ...
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1answer
27 views

Pyqgis Qgis2 override Processing framework settings doesn't work

Inside my Python plugin (qgis2.18) I use some Processing algorithms. I'm trying to override the Processing setting that allows using only the selected features. I' want to set it to False and ...
7
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1answer
146 views

'native' vs. 'qgis' geoprocessing algorithm provider in (Py)QGIS 3

In QGIS 3 processing toolbox among all the algorithms with the QGIS 3 icon there are some with Algorithm-ID starting with qgis: and some starting with native:. What is the difference between ...
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1answer
43 views

Definition of OUTPUT parameter in PyQGIS 3 processing algorithms

In PyQGIS 2.X I could handle the output of processings algorithm as follows: import processing # None is the OUTPUT parameter here buffer = processing.runalg('qgis:fixeddistancebuffer', ...
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1answer
52 views

Error in executing Voronoi polygon algorithm

I am trying to create Voronoi polygon on point layer of my project. I need to save this new layer as .shp file. The following is the code I have written in Python console, using QGIS 3.0 import ...
1
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1answer
40 views

qgis:JoinAttributeTable is giving a Syntax Error in QGIS 3.0

I am new to QGIS 3.0 and using "qgis:Joinattributetable" for joining .csv and .shp file. Below is my code, but I am getting Syntax Error. AttributeError: module Processing has no attribute '...
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0answers
156 views

Python processing script with clip in QGIS 3.2

I have been following the QGIS scripting templates, but have been unable to get vector processing to work with input and output layers. Working with QGIS 3.2.2. The following script is my attempt at ...
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0answers
57 views

Create lines to connect vertices in QGIS

I have a file that marks street edges and want to connect "crossing" points automatically. Image 1 shows the street edge, Image 2 shows the desired result. Is there a plugin or method I can use to ...
3
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0answers
177 views

Couldn't load plugin 'processing' on starting QGIS3 on a mac

I'm getting an error message when I start QGIS3. I've tried all sorts but don't know what else to do? Couldn't load plugin 'processing' ImportError: cannot import name 'ogr' Traceback (most ...
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0answers
26 views

Algorithm “qgis:difference” doesn't work in pyQGIS 3

I try to use native algorithm difference of QGIS. But it seams it doesn't work like the others : parameters = {'INPUT': polygons['OUTPUT'], #from temporary layer created before 'OVERLAY'...
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0answers
9 views

Locating Local Anomalies in NDVI with Vector Overlay

I am attempting to identify potential leaks (exploiting an extended dry spell in the weather) from shallow underground pipes running under fields by flagging areas of anomalously high NDVI values. I ...
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0answers
75 views

QGIS 3.2 Grass processing algorithms not working

All the Grass processing algorithms I have tried on windows 10 QGIS 3.2.1 give me the error below. Anyone else experiencing this? Any solutions? Processing algorithm… Algorithm 'v.buffer' starting… ...
1
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1answer
111 views

Plugins repository is unavailable

I'm using QGIS 2.18.20. On MacOS High Sierra 10.13.5 Only recently I haven't been able to find uninstalled plugins. The settings show the repository is "unavailable". I'm not using a proxy. I've ...
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0answers
34 views

Debugging Error: Algorithm gdal:dissolve not found in PyQGIS?

I have difficulties with the processing package. I try to run a simple QGIS dissolve in pyQGIS 3. When I run the line : from qgis.core import QgsVectorLayer import processing from processing.core....
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1answer
62 views

Distance Matrix with 2 point shapefiles and one street network

I have two point shapefiles (start/destination) and one sort of street network shapefile. I would like a to create a distance matrix from the start-shapefile to the destination points, using the ...
1
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1answer
67 views

Error: Algorithm not found with correct processing use

I try to run a simple dissolve algorithm in a standalone Python 3 script. My code is following : from qgis.core import QgsVectorLayer import processing from processing.core.Processing import ...
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0answers
16 views

Changing name of outputlayer dynamically in QGIS Processing script?

I have a processing script to load txt-data from a magnetometer and convert them into a vectorlayer (to make a raster in a second step). I want the name of output layer to be changed into something ...
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2answers
41 views

Statistics on grid cells over GRID format file layer

I have state wide data here that I would like to overlay a grid layer of 1kmx 1km onto. I used the processing toolbox in QGIS 3 (Create Grid) in order to create a grid layer of 1km x 1km lines under ...
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0answers
38 views

QGIS Processing v.net.distance Error

I am hoping that someone can point me in the right direction. I am wanting to calculate the distances from a point to each point in another layer along a road network using v.net.distance. I have done ...
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0answers
15 views

Altered Minimum Bounding Box Algorithm [duplicate]

I'm trying to create an algorithm similar to minimum bounding box (though it may end up looking nothing like it). In this case the angle will be passed as a parameter and given the angle I need the ...
1
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1answer
44 views

Correct way to delete a field, add a field and update attributes in pyqgis

I am working on a script that runs a model and then appends the result to a spatialite layer. The model runs zonal statistics using 4 different rasters and appends them to the attribute table of a ...
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2answers
72 views

Processing toolbox nowhere to be found

I have just downloaded the newest version of QGIS (3.2) and the processing toolbox is nowhere to be found. It says that it is now apart of the core package, but i cannot find it on anywhere on the ...
2
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1answer
42 views

How to call “Clip Raster by Mask Layer” tool using QGIS console? (gdal:cliprasterbymasklayer)

I execute the followng code in QGIS 3.2.1 console, but Clip Raster by Mask Layer tool doesn't work - output file is not created. Here is QGIS console output: None # perhaps this None appears as a ...
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0answers
18 views

semi automatic plugin v value in automatic threshold calculation

what does the 'v' defined value stands for in automatic threshold calculation in semi automatic plugin in QGIS
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1answer
129 views

QGIS 3.2.0 on Mac Sierra 10.12.6 not loading Processing / Vector / other toolbars

I've already changed the Environment to enable "Use Custom Variables" and added a "Prepend" "PATH" ""/Library/Frameworks/GDAL.framework/Programs:/Library/Frameworks/Python.framework/Versions/3.6/bin:""...
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1answer
37 views

Getting count of overlapping portion of different line features within one shapefile using QGIS?

I have a line shapefile that has overlapping on certain portion of the line features. I need to know the count of where these overlapping occurs and if there is no overlap to keep it as Null or 0 as ...
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1answer
79 views

Adding LWGEOM to QGIS 3 Processing Toolbox

In 2.x versions of QGIS I was able to add LWGEOM to the QGIS Processing Toolbox and run the Make Valid command. Using OSGEO4W, I've downloaded QGIS 3.2.1 and also downloaded the latest LIBLWGEOM, but ...
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0answers
22 views

Selecting pixels in raster using polygon selection tool in QGIS?

I want to reclassify landcover image manually with respect to online imagery. I am looking for a software/plugin/script to manually select raster pixels using polygon selection tool and could be able ...
1
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2answers
36 views

QGIS - Layer style categorizing insert missing values

In QGIS Bonn, when styling my layer to use the categorize option, I want to have all values within a range, for instance, 0 to 50000. I am using the data from a CSV that has information about ...
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0answers
43 views

Programatically checking if field is empty in QGIS?

As part of a complex workflow which will involve several models in QGIS 3.2, I would like to check if all features in a layer resulting from a model's output do not have an empty value on a specific ...
5
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2answers
763 views

Ignoring invalid input features with Intersection tool in QGIS?

In QGIS 2.18, when I used the Vector > Geoprocessing Tools > Intersection tool, I was able to check an option which said "Ignore NULL geometries [optional]". Now I've downloaded QGIS 3.2 and that ...
0
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1answer
73 views

How to output multiple raster in QGIS processing scripts

I am writing a script in R for running in QGIS processing. The code is a oil spill classification algorithm and depending on the number of polygons which user inputs in the shapefile, output raster ...
2
votes
1answer
37 views

How to input an array in R script running inside QGIS

I am using QGIS 2.18.21 and running an R script which needs various files as inputs. The number of files to be inputted is also entered by user. I am thinking of taking the input of all file paths in ...
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0answers
61 views

v.rectify don't work properly from processing toolbox in QGIS 3.2

I would like to use the tool "v.rectify" from GRASS in my plugin, but when I call it, it continues to say that "ERROR: Required parameter 'output' not set", although this parameter is set. I think ...