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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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?
20
votes
1answer
415 views

Performing QGIS modeler multiple raster calculations with data from external CSV?

I need to perform multiple calculations on a set of rasters based on values in a CSV metadata file. I'm using the QGIS graphical modeler and can call a specific field in a CSV with the Table and ...
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,...
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 ...
10
votes
1answer
307 views

Why is QGIS graphical modeler modal?

I often switch between graphical modeler and the main QGIS application and wonder why I am not able to operate QGIS when modeler window is open. Saving my models and closing / reopening modeler annoys ...
10
votes
1answer
1k views

QGIS Modeler if/else condition, custom script for Modeler

I want to make a simple if/else function inside my Model and I wanted to know if it's possible or not. I want this thing to do that if an Input for 'Segment Layer' is selected that it doesn't have ...
9
votes
2answers
2k views

Saving processing results in a file using QGIS modeler?

From a model, I would like to save processing results in a file. In my model I have some Extract by location algorithms (with two vector inputs) producing reasonable results but only as temporary ...
9
votes
1answer
386 views

Conditions in modeler field calculator

I want to check a vector file if there is a column "Source". If yes, nothing to do. If there is no column "Source" it should be created and filled up with '0'. Is this possible to do via the ...
8
votes
2answers
436 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 ...
7
votes
2answers
594 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 ...
7
votes
1answer
207 views

QGIS Graphical Modeler Add Specific files

When I create a model in the Graphical Modeler Tool I need to add layers using ‘Add File’. When I run the script, I have to add the same files each time (Which can lead to adding numerous files). ...
7
votes
1answer
272 views

Two Selections from one Layer in Processing Modeller

I have the following problem: I try to do two parallel selections. For this I have applied before the "extract by location" algorithm. Now I would like to execute in the next step from this layer two ...
7
votes
1answer
419 views

Interpolating Daily Values from Monthly Grids using QGIS?

I am currently performing a bioclimatic analysis using monthly averaged climate grids. One particular calculation, Growing Degree Days, relies on daily maximum/minimum temperature and a threshold ...
7
votes
1answer
359 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 ...
7
votes
0answers
318 views

Merge Raster Layer Specific Order in Graphic Modeler [closed]

I'm using the Graphic Modeler/Processing Modeler to automate a process. The last step in this process is Merging three different Raster Layers. I'm using the "Merge Raster Layers" from Saga 2.0.8. Is ...
6
votes
1answer
165 views

Graphical modeler calculator missing in QGIS3

There used to be a calculator in the modeler-only tools in QGIS graphical modeler. But I notice that it is missing in QGIS3. How do I do numerical calculations as part of the model? For example, take ...
6
votes
1answer
198 views

How to use optional inputs in model processor for QGIS 2.18/3.0?

I have developed a processing model in QGIS 2.18 where all my inputs are optional and I need them to be truly optional. However, the model will not run unless I have all inputs present. I have tried ...
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?
6
votes
1answer
169 views

QGIS equivalent of Calculate Adjacent Fields for Atlas

Is there a QGIS plugin available or a processing model to calculate and populate fields that can be used to label the adjacent pages in a map book? Although there are tools to create vector grids, I ...
6
votes
1answer
401 views

Interpolating a string input into an output layer name in QGIS' Graphical Modeler

I believe that the answer to my question is 'no' but am hoping that I missed something in my Googling and trawling of StackExchange... I have a simple Graphical Model built in QGIS (2.12) that asks ...
6
votes
1answer
349 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 ...
6
votes
1answer
435 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 ...
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 ...
5
votes
3answers
902 views

Clipping line layer to every feature of polygon layer in QGIS?

I have a line layer (roads) and a polygon layer which represents districts/counties. I want to clip the roads according to every one different county. That means that I must repeat the procedure sixty ...
5
votes
2answers
577 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 ...
5
votes
2answers
207 views

Usage of QGIS Dissolve geoalgorithm in QGIS Graphical Modeler (2.18.19 LTR)

When I use QGIS Dissolve geoalgorithm as a standalone tool from the Processing Toolbox, the GUI looks like shown below. By selecting the Input layer I am able to chose from its attributes on wich to ...
5
votes
1answer
193 views

How to use Replace function in a custom script?

I would like to use Replace function in a QGIS model but it doesn't work as I wish. I was working with Joseph's brilliant solution (using a custom script in a model) but I couldn't find out how to ...
5
votes
1answer
514 views

QGIS Count lines in polygon ( to be part of a graphical model )

My problem is very easy to understand but I can't find a solution. I'm actually working on the spreading of a local optic fibre network. These fibres will be contained in plastic tubes buried in ...
5
votes
1answer
769 views

Adding date field to attribute table using QGIS processing modeler?

I want to add a date field to my output layers attribute table, using processing modeler. I want the Date field to be a parameter in my model, because I want to manually input the Date everytime I ...
5
votes
1answer
837 views

Defining “Style file” of QGIS modeler process “Set style for raster layer”?

I want to add "Set style for raster layer" to QGIS processing modeler but I have no clue how I need to define the "Style file" field. I have a layer style document and I assume, I need to define a ...
5
votes
1answer
809 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
334 views

Setting constant input layer in QGIS modeler?

I have a model in QGIS where there are two vector layers that remain the same everytime I execute a model. Is there a way that I can configure my model so that these layers don't require the user to ...
5
votes
1answer
227 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 ...
5
votes
1answer
428 views

Referencing another layer in Field Calculator inside Graphical Modeler

I want to use the Field Calculator inside the Graphical Modeler to create a new column in an input vector layer (LAYER1) using data in another layer (LAYER2). LAYER2 is the output of another algorithm ...
5
votes
1answer
608 views

QGIS 'Join attributes by location' algorithm (sometimes?) not working properly in graphical modeler

In QGIS 2.14.10 I've set up a simple model to assign min and max of attributes of a point layer (adresses, about 2500 features) to a polygon layer (parcels, about 14000 features) to polygons ...
5
votes
1answer
90 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 ...
5
votes
1answer
167 views

QGIS- Model works on single layer execution, errors out when run as batch

I have a pretty simple model in QGIS that I am trying to use as a batch process. The model takes a line shapefile input, creates a temporary buffer, extracts by location using that created buffer, and ...
5
votes
0answers
53 views

Referencing an output in an expression in process modeler

In the process modeler, I'd like to reference an output of a previous step as one of the parameters of an algorithm. In this case, the previous step was clipping a large raster and I want to use the ...
5
votes
0answers
103 views

Using Layer Parameter variables in Field Calculator within QGIS Model?

If I define a Vector Layer as an input parameter to a QGIS model, then the parameter name is exposed as a variable in a Field Calculator within the model, however I am unable to use this variable as I ...
5
votes
0answers
133 views

Creating Viewsheds in Graphic Modeler

I am trying to use Graphic Modeler to run viewsheds. As I can’t appear to use the Viewshed Analysis plugin tool in Graphic Modeler and I instead need to use the GRASS command r.viewshed. I am ...
5
votes
0answers
97 views

Selecting minimum number of neighbouring polygons required to give a fixed total area

I have a polygon layer. I would like to select the minimum number of neighbouring polygons to give a total area greater than a fixed value. In reality the polygons are land parcels and I would like to ...
5
votes
0answers
318 views

QGIS modeler - use input filename in output filename

I need to use the input filename in the output filename in a QGIS model. I have spent a couple of hours trying to find a solution but can't. If the input is contourXY.tab and I want output to be \...
4
votes
2answers
720 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 ...
4
votes
1answer
110 views

Decimal Numbers in the Graphical Modeler

How do I set up an input field that accepts decimal numbers in the QGIS graphical modeler?
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
626 views

How to use the 'File' type inputs in QGIS modeler?

I would like to add a field to all shp-files in a directory and calculate the area. I tried with the parameter "File" but didn't find a way to conncet this input to the other algorithm/operators.
4
votes
2answers
881 views

Adding today's date into attribute table using QGIS Processing modeler?

I am looking for a way to use the Processing modeler to add a date field to an output dataset in QGIS 2.6.1 I have tried using the field calculator algorithm without success. (Also the advanced ...
4
votes
1answer
672 views

Programmatically naming outputs from the QGIS Modeler?

I am attempting my first use of the modeler from the Graphical Modeler from the Processing menu in QGIS (2.18.3). I made a simple model for using meanshift segmentation. It just has a raster input and ...
4
votes
1answer
742 views

Table output from QGIS graphical modeler

I have developed my own model, which processes input vector layer. The final output is vector layer that contains many attribute fields, and of course, also the geometry, but I need a simpler output - ...
4
votes
1answer
132 views

QGIS 2.99.0-149 modeler inputs Feature Source vs. Vector Layer

In QGIS 2.99.0 modeler, there is a obviously a new input type called Feature Source, wich does what Vector Layer did in previous versions (but Vector Layer is still available): New behaviour, as can ...