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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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7
votes
2answers
595 views

Why “Export as Python script” button is unaccessible in QGIS 3.0/3.1 Modeler by default?

In QGIS 3.0, "Processing Modeler" window has no "Export as Python script" button unlike QGIS 2.x. If you look at the codes (in DlgModeler.ui and ModelerDialog.py files), you see the code lines ...
4
votes
1answer
1k views

Number inputs as raster calculator variables in QGIS Modeler

How can i use input numbers as variables in any of the raster calculator algorithms in QGIS through the modeler? One very simple example of that would be a model that allows me to divide raster cell ...
28
votes
5answers
10k views

Seeking model builder for QGIS?

Like the ModelBuilder of ArcGIS Desktop to run simultaneous geoprocessing tools, is there any model builder available in QGIS?
6
votes
1answer
678 views

Using QGIS 2.x processing model in QGIS 3.0?

Is it somehow possible to convert a QGIS 2.x processing model (*.model) to a *.model3 so i can run them in QGIS 3.0 without having to redo mine from scratch?
3
votes
1answer
921 views

Why does “Join attributes by location” fail to compute sums when used in a model?

If I use "Join attributes by location" from the menu it works fine but if I'm using it within the Processing modeler it's not working. I want to sum up previously selected records having a field area ...
1
vote
0answers
559 views

Why can't I use processing algorithms in a standalone PyQGIS script?

I want to create a standalone python script using QGIS python API (PYQGIS) for education. First I create a model and export that model to python script. original python script from the export : ##=...
13
votes
1answer
3k views

Simplify repetitive tasks in QGIS Graphical Modeler

Are there iterators that can be used in QGIS graphical modeler to simplify the model shown above. If not, is there any better way of simplifying the model? The first column represents my input layers,...
4
votes
1answer
2k views

How to connect input parameter to the field calculator algorithm within the graphical modeler?

I am building a model in the graphical modeler of QGIS 2.8.1 Wien and I would like to give the option to the user to enter a number in the model with which a selected field will be multiplied, but I ...
4
votes
1answer
1k views

QGIS Modeler: Where is output from algorithm 'Set style for vector layer'?

I am writing a model that takes a polygon shapefile as input, converts it to polylines, explodes it to individual lines and finally applies a (tested) style, khLineLength1.qml, which labels each line ...
3
votes
0answers
211 views

QGIS spatial sort - coalesce?

In QGIS (v3.2) is there a spatial sort similar to ArcGIS (http://desktop.arcgis.com/en/arcmap/latest/tools/data-management-toolbox/how-sort-works.htm#ESRI_SECTION1_9C199CD3D68A41029943D4FF79500A73) ...
2
votes
1answer
233 views

Join attributes by value in QGIS 3.4.3 Processing Modeler

I want to add only a few specific columns from the join table but there is no drop down list. When selecting manually I'm able to select only 1 column when trying more than 1 I'm not getting the ...
1
vote
1answer
284 views

How to link Number value with Field calculator in QGIS Modeler ?

I want to link 2 number values (RMSE & dosemax) in a field calculator formula. When I run the modeler, I add these values but it doesn't recognize them. I dont want to create a new table. Just use ...
5
votes
2answers
581 views

Run QGIS Model on selected features only?

Would it be possible to run a script in a QGIS model so that it only runs on selected features from an input layer? I don't want to use the option in the toolbox options as I have other models that ...
4
votes
1answer
291 views

Using relative path in QGIS 3.0 Processing Modeler?

Using QGIS 3.0, we are working on creating a tool that will allow people to check that their snapping is correct with several linear features stacked on each other. A co-worker of mine figured out how ...
3
votes
1answer
459 views

QGIS modeler: select by attribute wrong results

I am new to QGIS modeler and trying to write a script in which certain attributes are selected and written to a shapefile. See the attached image for the script and the select by attributes box. In ...
3
votes
1answer
136 views

Ensure model runs from a specific layer?

I have some models for various routines but I really want them to run on a specific layer. I don't want to be able to run the model with any input layer as if done so by accident it can mean crashing ...
0
votes
1answer
396 views

CSV list as input parameter in QGIS 3.0 Processing Modeler

I have CSV list with XY coordinates (company and its competitors) which I want to input into simple QGIS Processing model. From this list the model creates and styles two spatial layers. Everything ...
12
votes
1answer
13k views

Syntax of conditional statements in QGIS Field Calculator(s)

I have a shapefile which I need to modify. There is one column "CLASS" with the attributes: "A", "B" and "C". I need to change "A" into "1", "B" into "2" and "C" into "3". I tried it with case when ...
8
votes
2answers
437 views

Using Calculator in QGIS Graphical Modeler

Since QGIS graphical modeler calculator did not lead to an answer, I'll try my luck here again. I created a simple model in QGIS 2.18.16 that shall calculate a distance based on the extent of a raster ...
6
votes
1answer
442 views

Adding field to table using QGIS graphic modeler?

I was wondering if anyone could help as I'm struggling to get anything out of the QGIS graphic modeler. I need to be able to add a new field to an attribute table and update that field with a value ...
6
votes
1answer
356 views

Cannot find layer error with Execute SQL in QGIS Graphical Modeler

I'm trying to sort a shapefile by one of its attributes using "Execute SQL", in the QGIS Graphical Modeler. Using a vector as input is working fine, but when I use a layer generated by an algorithm ...
5
votes
3answers
174 views

Arranging GUI elements in QGIS 3 processing model user interface

Using QGIS 3 graphical modeler I created a model with a variety of input parameters (> 10). When starting the model, a nice user interface is generated. But the arrangement of the GUI elements is ...
4
votes
2answers
723 views

Selection input for QGIS Processing models

QGIS 2.14.11 LTR. In a processing script we can define a selection as input parameter by ##auswahl_test=selection spam;egg;dummy resulting in Background is, that I want to provide a selection of ...
7
votes
1answer
360 views

Processing modeler Output Order

I have a model running on the processing framework it produces a serie of vector layers as output(alt-0, alt-1, alt-2, alt-3, and so on). I have prepared the model keeping the order of these ...
5
votes
1answer
822 views

QGIS processing default output vector layer extensions

You can set the default output-extension of a model in processing > options > general. The intermediate transactions in a model are processed in that default file format. After installing QGIS, the ...
5
votes
1answer
94 views

Order of parameters in QGIS 3.6 graphical modeller

When using graphical modeler in QGIS 3.6 I have added additional parameters to the model inputs for the buffer tool. The model looks like this: When running the tool the order of the parameters in ...
4
votes
1answer
1k views

Using a plugin in QGIS modeler

I am working on a project where I want to automatize the workflow using the QGIS graphical modeler. The problem is that I want to use the Group Stats Plugin as a part of my model but can't integrate ...
4
votes
1answer
265 views

Graphical modeler in QGIS 3.0.3 - Access Vector Field in Calculator

I want to create an algorithm with the graphical modeler in QGIS 3.0.3 where i define one Vector Layer and a Vector Field from this Layer as my inputvariables. Then i want to access the field-values ...
4
votes
0answers
756 views

Problem loading output layer QGIS

Every time I run operations with temporary file output from the graphical modeler, I get the following error message: Oooops! The following output layers could not be open CLIP: C:\Users\Amine\...
3
votes
1answer
508 views

QGIS graphical modeler calculator

My question is about the calculator in the QGIS graphical modeler. I explain my problem issue first: I want to build a modeler that creates buffers around layers and makes a selection on a second ...
3
votes
1answer
44 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 ...
3
votes
1answer
134 views

Sort inputs parameters in QGIS modeler

I created a model in QGIS 3.6 with three inputs parameters (two vector layer and one vector field). When I run the model, the inputs are not sorted in a correct way: the vector field is requested ...
3
votes
1answer
1k views

How to use QGIS Graphical Modeller to join specific fields?

I wish to join one field from a shapefile to another shapefile within the QGIS graphical modeler. I am aware that there is a 'Join attributes table' algorithm but this joins all of the fields from the ...
4
votes
0answers
79 views

Model script works in QGIS 2.14 but not 2.18 [closed]

I created a model that worked fine in QGIS 2.14. With help I included a script in the model that prevented the model from running unless a feature was selected. But after upgrading to 2.18 the model ...
4
votes
1answer
189 views

Geometry by expression in QGIS Modeller

I want to use 'Geometry by expression' in a model I'm working on but I couldn't figure out how to pass the layer name parameter. Basically I have two polygon layers (A and B) and I want to do a ...
3
votes
1answer
360 views

QGIS Modeler algorithm does not accept input variable

I am trying to make a QGIS model which includes an "Extract by Attribute" algorithm. One of the inputs for this function is the liminar value, simply called "Value". For some reason though, it is only ...
3
votes
2answers
129 views

How to use fields mapper in qgis modeler?

I am building a modeler in QGIS 3.2.1, I want to use Refactor fields tool to change the name of a fixed field (fid to org_fid),This tool accepts a Fields mapping. I also noticed that there is a Fields ...
3
votes
1answer
269 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 ...
3
votes
1answer
156 views

Incorrect result while adding points along geometry in QGIS

I'm trying to add points along lines every 3 metres but I'd like the starting/ending point at certain non fixed distance. When I use the tool 'Points along geometry' inside Graphical Modeler. I don't ...
3
votes
2answers
2k views

Zonal Statistics for multiple rasters

I'm trying to create a timeseries of raster data (one layer per year) by polygon (Administrative regions). Is there any way in QGIS to perform Zonal Statistics for multiple years (without having to ...
3
votes
3answers
147 views

Automatically populate r.reclass rules based on table values

In QGIS I have a raster map showing land, snow and cloud zones, having resp. pixel values 1, 2, and 3. I extracted the mean altitude values (in m) of each zone on the basis of an underlying DEM and ...
3
votes
1answer
150 views

Syntax for “fields to keep” of Intersection tool in graphical modeler

I'm working with QGIS 3.2 Bonn and try to set up a workflow with the graphic modeler. The model uses the Intersection Tool from the QGIS Geoprocessing Tools. The model works, but I don't want to ...
3
votes
1answer
267 views

How to multiply a user-defined input parameter with a field value within the graphical modeler?

I have the same Question as asked in this post (How to connect input parameter to the field calculator algorithm within the graphical modeler?) and the answer from Joseph already helped a lot: ##...
3
votes
1answer
112 views

Issue with “Join attributes by field value” on QGIS 3.4.7

I have a shape file with polygons and a xlsx sheet, and I need to join their tables using Join attributes by field value in the modeler. At QGIS 2.18 it works perfectly, but in 3.4.7 the join doesn't ...
2
votes
1answer
2k views

QGIS modeler: Error when extracting by non existing attributes. How to avoid displaying of error?

I have a problem with the QGIS modeler: The idea is to extract attributes ("DN" between 40 and 44) out of one layer. I want to use the outcoming layer for further algorithms. I calculated with ...
2
votes
1answer
709 views

QGIS Model Builder Script - Possible to merge layers in a folder?

I would like the user to select a folder via the interface in which all the vector shapefiles inside that folder would be merged. I have been using the Model Builder and looking at example scripts ...
2
votes
1answer
250 views

Accessing input layer properties from QGIS Modeler?

So I start my model by dragging an input layer, which in my case it happens to be a vector layer. Let's call it inputVectorLayer. Later on in the model I want to refactor this layer using the Refactor ...
2
votes
1answer
80 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 ...
2
votes
2answers
765 views

Select by location is not working in the processing modeler

When I run the modeler in qgis 2.14 I get no results from the select by location algorithm. I tried outputting my buffer polygon and using the select by location plugin and it worked fine. I have ...
2
votes
1answer
763 views

QGIS Python Scripting - Syntax definition

After playing around with the QGIS Modeler and looking at the python scripts of what I make, I noticed some syntax which I can't find the definition anywhere. Here is a snippet of the python script ...