Questions tagged [qgis-modeler]

An application of QGIS used to develop models utilizing a large variety of powerful Geoprocessing tools via a GUI.

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26 views

QGIS Raster calculation fails in Graphical Modeler

I'm trying to use the graphical modeller to automate a certain process (extracting North-South facing slopes from a DEM). The process is as follows: Calculate Slope Calculate Aspect Extract North-...
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20 views

Can Project Home variable be used to save default outputs of QGIS graphical modeler

Is it possible to use the @project_home variable in QGIS to set a default file path location for an output in the graphical modeler? Ideally I would like the default to be the project home folder ...
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1answer
35 views

How to delete features selected by expression using graphical modeler in QGIS3

I can't find an algorithm for deleting features (points), so I can't delete features in the graphical modeler. I found related information (Select by expression and remove points). However, I want to ...
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2answers
85 views

QGIS expression, define start and step increment

This is a continuation of the question QGIS Extract by Expression with multiple polylines in Processing Modeler I have polylines with increasing values, Gabriel De Luca helped me to automate the ...
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0answers
27 views

Exporting rendered raster image from graphical modeler

I am new to using the graphical modeler and am trying to export the result raster from my model as a rendered image. Basically trying to replicate what happens by doing the following to the result ...
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2answers
141 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 ...
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1answer
13 views

Add an attribute name as parameter in refact - QGIS 3 modeler

I'd like make a model where I can change an attribute name to a predefined one using refact tool. How can I get that "attribute" by a parameter from a vectoral field ?
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20 views

Set the Output of a script as Input of another one

What is the correct way to call the output file of a script? Since QGIS can't name it automatically. I have this script that works perfectly, just drop a file identical to the original. from qgis....
2
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1answer
39 views

Ask for polygons but getting points with QuickOSM in QGIS Modeler

I am attempting to download both points and polygons using QuickOSM+modeler in QGIS 3.10 (also tried QGIS 3.8). It's downloading the points fine, but when I attempt the same thing with multipolygons ...
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19 views

Qgis SAGA Upslope Area for several points automation

In the Upslope Area tool from SAGA it used to be possible to import the point file with multiple points and it would create several catchment/basins areas for those points. Now, it is only possible to ...
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1answer
24 views

Creating Dialog with Graphic Modeler for Attribute Creation

I have a shapefile with an attribute that I need to convert based on categorical rules. Hereby the TARGET / new values always stay the same and only the input values change. For example: "Residential ...
3
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1answer
104 views

QGIS Extract by Expression with multiple polylines in Processing Modeler

I'm trying to get the matching features from an intersecting vector layer. I can manually open Extract by expression tool and put the expression like intersects($geometry, geometry(get_feature('Liness'...
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17 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 ...
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34 views

Manually giving input and output for QGIS graphical modeler exported python script

I am using QGIS 3. How could I manually give the input layer and the output path to the following script extracted from the graphical modeler? It is a simple model, it takes a DEM as input and ...
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0answers
33 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 ...
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1answer
253 views

Extracting features with equal field value using graphical modeler of QGIS

Is it possible to automate the following procedure with graphical modeler in qgis 3.4 or is it easier to perform such action with a python script using PyQGIS? Identify a feature (a line) in a vector ...
2
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1answer
37 views

Sort or add Rank within QGIS 3 model

I have the following function in order to add a sorting value to a layer: array_find( array_sort( array_agg("field")), "field") This works fine if I use it through the calculator within the ...
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52 views

Error while running batch processing in QGIS 3

I have built a straightforward model in the Graphical Modeller in QGIS 3.4 to select features by expression and then save the selected features to a new shapefile. It works when running singly but ...
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2answers
145 views

Using Viewshed Graphical Modeler

I am trying to create a viewshed using the graphical modeler, the first part involves creating the viewpoints which works fine, however when I create the viewshed I get the following error. Also, when ...
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17 views

Join fields QGIS processing framework [duplicate]

Using QGIS 3.4.12-Madeira I'm building a model using the algorithm 'Join attributes by location'. In my operation i want to join several fields from a layer, but not all. I tried to set one field ...
3
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2answers
65 views

Iterate over all attributes in QGIS Graphical Modeler

I would like to iterate over N unknown attributes in the QGIS Graphical Modeler. For example dividing all attributes in an input layer by its area to create an area weighting. I realise it could be ...
2
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1answer
40 views

How to call for Matrix Parameter / Enum Parameter using Field Calculator in the graphical modeler of QGis?

I am using QGis Graphical Modeler v.3 It is possible to define, as an Input, a Matrix, defined as follows: "A table (matrix) parameter for processing algorithms". I want to use values stored within a ...
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1answer
114 views

Converting Model in Plug-in in QGIS

Recently, I started making a model on QGIS and now I want to transform it into a plug-in, but it seems that I have to change the code to do it, otherwise it won't work. What changes are required to ...
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1answer
258 views

Exporting result of QGIS model to CSV

I am trying to output the result of a QGIS 3 model as a CSV file. At first I came across How to export csv/excel in QGIS3.0 model processor? but the accepted answer is not satisfying to me. Further ...
2
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1answer
36 views

Collapse rows with different attributes in QGIS modeler

I am trying to build a QGIS modeler tool to do the following; I have a parcel table with fields "OWNER" and "OWNERNO" where each owner has their own row in the table and the "OWNERNO" numbers them. (...
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34 views

Using project layers as input to the graphical modeler exported script in the Python console (QGIS)

I have created an workflow wothin graphical modeler in QGIS. Now I want to use the code exported from the graphical modeler in the python console. How could I use the layers from my project as ...
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1answer
46 views

QGIS 3.4.4 edit rendering styles for outputs - styles not loading

I have created a processing model in version 3.4.4 and I want the shapefile outputs from the model to load in a chosen style. I have saved the style files and used the 'edit rendering styles for ...
3
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1answer
69 views

Standalone Python application from QGIS graphical modeler

I am trying to run the script generated by my graphical modeller through QGIS script. But I get the following error. # Prepare the environment import sys from qgis.core import QgsApplication #from ...
2
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1answer
101 views

Change Output name in Script - QGIS 3

I exported a model as script using the properly option in QGIS 3.8. The Script works perfectly, but the output name is changed. Heres a print of the model: I want that the script´s output name, from ...
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0answers
43 views

Problems with Zonal Statistic in graphical modeler QGIS 3

I want to make an average of two rasters previously generated in a model but it always gives error. I have used both SAGA and GDAL to calculate the raster out of graphical modeler without problems, ...
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1answer
94 views

QGIS 3 Graphical Modeler field calculator with attribute's parameters

I want to make a model with a vector layer to calculate the sum of two parameters contained in the attribute table of the layer. I want to create two variables in the model, the name of the two ...
3
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1answer
50 views

Rotation goes Wrong

I have a model that I built using model builder that creates a rectangle grid and then rotates it. For some reason, when I use rotate, it creates something wrong- and it creates''holes'' between the ...
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2answers
51 views

Realising vector file mapping using QGIS Modeler?

I pretty often get lots of vector files with different column namings. I need to produce a defined vector data file with certain columns. Is it possible to build a model that allows to make a mapping? ...
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17 views

Using Model Builder for QGIS? [duplicate]

I'm looking for a "model builder" for QGIS 3.2.1. If that kind of tool exists, could someone share some related topic showing how to use it?
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22 views

Raster Calculator in the Graphical Modeler of QGIS 2.18

How to convert this expression from raster calculator ("noise_heatmap_clip@1" <= 50) * 5 + ("noise_heatmap_clip@1" > 50 AND "noise_heatmap_clip@1" <= 100) * 4 + ("noise_heatmap_clip@1" > ...
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1answer
44 views

Using Multiple Raster Intermediate Inputs in Raster Calculator within QGIS Process Modeler

I am stringing together a series of raster calculations in the QGIS process modeler in order to calculate a surface temperature dataset from Landsat and weather data. When I use the output from ...
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0answers
45 views

Raster statistic

i'm try to use QGIS processing modeler but I've a problem. I need to use the Mean value and the standard deviation in raster calculator algorithm. I've calculated it in raster statistics, how can I do ...
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1answer
30 views

QGIS Modeler - drag and drop data from ToC

Is it possible to drag and drop data from the ToC to a graphical modeler and then draw connections between data and algorithms? Also can we do the same with items in the history panel? This would ...
3
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1answer
58 views

Adding a Geopackage layer as a hardwired input to an algorithm in the QGIS graphical modeler

I have a geopackage layer that I want to always be used in an algorithm in the QGIS 3.6 graphical modeler. When I use the triple dots to navigate to the geopackage it doesn't give me the option to ...
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2answers
53 views

Downloading files with file paths informed by attribute information

I am looking to download files that are saved in a server location with a file path that is informed by attribute information created in the graphical modeler. The information that I would like to ...
2
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0answers
120 views

QGIS3 run model with python script

I want to run a model with a python script, including the parameters, because I can't "translate" the model easily into a script. I have tried to run a copy of the processing log after running the ...
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0answers
19 views

Loading rasters from a GeoPackage into QGIS modeler based on attribute information?

I am looking to load raster layers from a GeoPackage based on strings of attribute information that is stored in a field. The process I am looking for is as follows: Site Boundary created before the ...
4
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1answer
158 views

Using variable in graphical modeler for raster calculation? (QGIS 3.8)

I am trying to create a flow in the graphical modeler using a variable in a raster calculation. Is there a way to use a variable directly in the raster calculator (SAGA or GDAL)? I know there was a ...
2
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0answers
45 views

Save Selected Features in QGIS 3.4 Model

I'm trying to build some models I have in QGIS 2.18. Each model uses the "Save Selected Features" geoalgorithm so that the model only runs on selected features in the source vector layer. In 3.4 ...
2
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1answer
55 views

Python error when batching a Graphical Modeler script [QGIS 3.4.9]

I have a very simple Model to convert a table in points and to extract some features by their attributes. I can run it without any problem, except if I do it as a batching process. I received this ...
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1answer
42 views

Writing comments in QGIS Graphical Modeler?

Is it possible to write comments in the Graphical Modeler (QGis) ? I want to explain my model step by step so anyone can easely understand what's going on.
3
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1answer
338 views

QGIS 3.8 model to Python script, not working in 3.4

I am using QGIS 3.4 but it does not have the option of saving a model to a Python script. So I installed QGIS 3.8, which has that option, loaded my model and saved it as a Python script. I loaded the ...
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0answers
24 views

QGIS 3.4 Modeler gives error on non-required parameter?

I created a model which is asking to input 20 OPTIONAL parameters for vector layers. But when the user does not enter a value for any of the 20 parameters, QGIS returns an error. Traceback (most ...
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0answers
21 views

Ability in QGIS modeler to just run a step or subsequent steps in a model

In the current QGIS LTR is it possible to just run one step or all subsequent steps in a model if the previous steps have all been run and are not changed? Sometimes steps take hours to run so if ...
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0answers
45 views

When using QGIS Modeler with geopackages is there any way to Extract one Specific layer when using clip function?

I would like to use QGIS modeler to allow extraction of certain layers of a geopackage. I am trying to clip a geopackage containing multiple layers using modeler and when run it the output gives only ...