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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27 views

How to select one field and delete all others QGIS graphical modeler

In the Graphical Modeler in QGIS I have the algorithm to Drop Fields, which you select the fields you want to drop: However, the vector layer I'm using has many fields but I just need one in the end. ...
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15 views

Expressions to Find data using QGIS Modeler

Im new to the expressions within the model builder. I have built a model already using two points as a Station And Backsight, with a line between them. Also my model computes a length of the line and ...
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22 views

Adding multiple vector files in a folder as an input in QGIS processing modeler using iterator tool

I have shapefiles in a folder that I intend to use as an input in QGIS Processing Modeler. I would like to iterate within the folder to add each of the shapefiles as an input. It did it in ArcGIS ...
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1answer
40 views

Extract JPEG out of raster based on rectangle location in QGIS

I have 10 overlaying rasters (both one- and multi-band) - same area, different date. I also have shapefile layer with 12 rectangle polygons. What I want is to extract proportion of raster inside each ...
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20 views

Algorithm “Merge Layers” from SAGA not showing in QGIS Modeler

I'm trying to merge multiple vector-layers via the modeler in QGIS 3.14.1 as a part of a bigger model. As a matter of fact the QGIS-native "merge layers" algorithm doesn't work here, for the ...
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18 views

Having wrong CRS from graphical modeler output

I'm using graphical modeler to reclasify some rasters and then make another calculus, but when I try my model only with the first step (reclassify) I get an output with different crs of the input. I'm ...
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30 views

QGIS 3.10 - Field calculator expression running in Attribute Table and not in Processing Modeler

I use the Field Calculator in the Attributes table and run the operation : "FieldA" - "FieldB", where "FieldA" and "FieldB" are height distances in meter with a ...
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29 views

QGIS Modeler: Additional Option don't work

I'm trying to automize clipping a raster obtained from an online source (WMS). It's all ok, when I do it step by step, but I need the final raster file to be compressed; and that's the point that ...
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1answer
47 views

Select by Expression in QGIS Graphical Modeler

I am trying to use select by expression or extract by expression in QGIS Graphical Modeler. I add a vector layer for input (have also tried vector features) I add the algorithm, select the input layer,...
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28 views

Conditions in Graphical Modeler in QGIS

I'd like to know if in the input/output panel we can choice (sort of check or uncheck) to insert an input value (numeric parameter or string..) instead of another, and also we can choice to run an ...
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1answer
37 views

Insert an input variable in a query in PostgreSQL

I'd like to insert an input variable (integer) in a query SQL (@variable) using the algorithm postgresql execute sql in the graphical modeler of QGIS. For example, in this kind of query INSERT INTO ...
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1answer
42 views

QGIS: Converting a QVariantlist from a GeoJSON to a List with some prefix removed

I have some problem seeming to converting a QVariantList from a GeoJSON file to a list in a new shapefile. Every time I just do the expression "Column" and just put the type of data as List ...
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27 views

How to integrate a Python Script into Processing Modeler in QGIS

I have a model in QGIS and I've generated a Python Script to calculate the matching between two strings (Levenshtein Distance with the FuzzyWuzzy Package) for one of the OUTPUTS. #####################...
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33 views

Using the conditional branch algorithm in QGIS modeler gives unexpected results

I'm trying to implement the new conditional branch algorithm in a model with the following statements: if( @Udtræk_til_grøfter_OUTPUT > 0, true, false) if( @Udtræk_til_grøfter_OUTPUT <= 0, ...
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37 views

How do I get the number of rows in an attribute table? [closed]

In processing modeler in Qgis 3.14, how do I get the number of rows in an attribute table?
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QGIS Modeler: Layer Rename does not output

I am currently in the creating a process in my QGIS model builder where I am trying to rename a finished process layer based on some best practice rules. Here is the model: Now here is the expression ...
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1answer
17 views

QGIS modelbuilder, having a choicebox/value map of strings as string input

I was wondering how you can get a choicebox/value map in the string input? Right now we have to type in value in but we would like to have it that has a choicebox/listbox to save time with typing.
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10 views

QGIS modeler, putting string into the parameters does not work with a refactor field expression

Currently I am trying to do build a model with some string input parameters that are being processed in a refactor field by an expression. However even though I clearly write some string text after ...
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10 views

QGIS Modeler, making a date “Calender” choice parameter as input?

Hello Currently I am trying to build a new model in the QGIS modeller. So far I have understand that I can predefine certain strings and with the refactor field give them as expressions in my new ...
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1answer
16 views

QGIS - Can't select Inputs for Select by Location algorithm in Graphical Modeler?

All the other questions I've seen so far are a step ahead of me. I've defined an Input for a vector layer, and am trying to use the Select by Location Algorithm. I typed the name of my Input, but the ...
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60 views

Workflow for Data Cleaning and Merging of Multiple Point Vector Layers in QGIS

I have multiple point vector layers in shapefile format. Each shapefile contains information of points (longitude and latitude) and datetime (in dd-MM-yyyy format). The problem is that some layers ...
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10 views

QGIS Modeler Selecting based on Geometry Shape: Line, Point and Polygon

I am in the process of building a model, where three layers (in a batch progress) there is currently one. Go through the same Refactor Field Alogrithm. However to make it more compeltly and to kind of ...
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16 views

Extracting the current feature in QGIS modeler iteration

I have a model that stopped working in the last few versions of QGIS 3.x. It worked fine in the past but now there seems to be an issue with the first step. Basically, the model is supposed to be ...
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1answer
25 views

QGIS modelbuilder Error on expression when similar Expressions Run Fine

I am currently trying to build a algorithm model that does some conversions of a attribute tables. It was working fine in a while I was building things step by step however a new expression does not ...
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33 views

Use base file name to reference created attribute in QGIS Modeler

I'd like to drop a field created when using overlap analysis. This operator creates two fields: [layername]_area and [layername]_pc. I want to drop the _pc. The input file name can vary. I've tried ...
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2answers
62 views

QGIS Modeler: Multiple layers going through the same process

Current I am trying to build a process model that edits fields and attributes of a collection of vector layer, the thing is though I can only select one vector layer and time to go through the "...
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0answers
24 views

QGIS: Creating a Custom Expresion for Field Calculations and the Model Builder

I am currently exploring Model Builder and I have some trouble setting a custom expression up for certain vector fields of a layer feature collection (points, line and polygons). This is the kind of ...
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1answer
39 views

QGIS 3.6 Model works but exported python script gives false results

As the title says, in QGIS 3.6 I made a model calculating "Forest fire susceptibility index - RC", model works fine and gives correct values. But when I export this model as Python script ...
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0answers
64 views

Getting layer id of processing step in QGIS graphical modeler for usage within aggregate() function

How can I get the layer name or layer id of the result of an processing algorithm within QGIS graphical modeler, so I can use aggregate() function in a later processing step? Is this somehow possible ...
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8 views

Rendering styles for output doesn't seem to be working

In QGIS 3.10, setting rendering styles for outputs in processing modeler by right-clicking my model works fine on my computer, but when the model and folder with qml-files is loaded on another ...
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0answers
23 views

Running an algorithm based on a condition

In QGIS 3.10, is it possible to only run an algorithm in the processing modeler if certain conditions are true? I'm applying concave hull to a layer, but sometimes that layer is empty and the model ...
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1answer
41 views

QGIS modeler: using input rasters filename for naming columns by expression

I am running QGIS 3.12.3 București on Windows 10 x64; I am building a simple model to reclassify a series of rasters with a 2x3 table, and then count each unique reclassified value within different ...
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26 views

Building a model to standardize rasters in QGIS

I have a little problem, but I think there is a simple solution, but I can't see it. I want to make a simple model for the rasters to standardize them using a simple formula: I want to compare the ...
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22 views

I cannot use Point entry into Graphical Modeler in QGIS

I would like to use a Point entry to get the point coordinates in the map to add in the network analysis as a start point. I have added the Point entry into Graphical Modeler, I can click on the map ...
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1answer
50 views

Save processing modeler output layers to project folder/relative path?

I am building an algorithm in the processing modeler which takes a csv file as input and creates a number of vector layers as output. I would like to automatically save these layers in the same folder ...
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2answers
72 views

QGIS Modeler: Extract by location, multiple predicates

I'm creating a processing model and would like to use the 'extract by location' tool, The problem is that when I choose this tool from the 'Algorithms' in the model creator, I cant find the double ...
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0answers
65 views

Issue with QGIS modeler raster calculator

I'm trying to apply a formula to scale an NDVI map from a WMS with QGIS modeler, but it keeps throwing me an error. I tried to do this without the modeler and it works. Here are the steps I want to ...
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0answers
57 views

QGIS Modeler using File/Folder input paramerter

I would like to use the File/Folder input parameter to set a path for all output layer files. I was trying to connect the File/Folder parameter to my output from a model and set a default folder path. ...
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1answer
42 views

How do I automate the production of a map series?

I would like to produce a series of maps in which each map contains the same layers, with each layer of a given type having the same styling from map to map, but the source of the half of the layers ...
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0answers
35 views

If/else condition in Model Builder QGIS 3.10 Batch processing

I have a set of images I need to process - all except one I have to calculate in Raster calculator with one expression, and the only one is the other expression. All following steps are the same for ...
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35 views

Create output folder for merge result of Model Builder on QGIS 3.10

I have export my model builder to python's script and now i would like to save the result to an created folder. But the folder name is based on a layer entity. Example: I have 3 layers (city, store, ...
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34 views

Two task at the same time in Model Builder QGIS 3

I am new to using the graphic modeler and I do not know how to do certain actions. I have several treatments to perform on the basis of a buffer zone. Indeed, I have to polygonize 2 raster (which we ...
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1answer
34 views

Apply Join by Location to a Selection in QGIS Processing Modeller

In QGIS 3.10.2 I have created a process modeler file that takes inputs from 5 input layers and creates a new layer as an output. The output layer is needed by an external program and the processing ...
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3answers
62 views

Dividing shapefile into multiple shapefiles using an attribute value in QGIS Graphical Modeler

I have a shapefile with a column that have project references, I want to create a different shapefile for every project reference there is. Note that the project references are not unique in the ...
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0answers
19 views

Automating sqlite to shapefile conversion using QGIS graphical modeler

I have a sqlite database with geospatial tables, I want to extract some of these tables into shapefiles (with all the shapefile files). Depending on an attribute (project name), I would like to ...
2
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0answers
62 views

Extracting several string values by attribute in QGIS graphical model

I am trying to extract several features by attribute within QGIS 3.12 graphical modeler. The values to extract shall be given by an input and not beeing predefined. Currently I am using a string-...
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1answer
31 views

Advanced Python Field Calculation gives error: TypeError: 'in <string>' requires string as left operand, not QVariant

I am using the following function in QGIS 3.10 Advanced Python Field Calculator as part of a Processing Modelling file. The model processed 4 layers and generates a single layer for use in another ...
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0answers
51 views

QGIS 3 modeler: how to use the fields of an intermediate output as input in another algorithm?

I'm working on a model to calculate land uses (usos) in different areas (zonas): I have corrected geometries, cutted the uses layer, corrected geometries again and used the fields calculator to ...
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1answer
97 views

QGIS 3.4 Add vector styles and attribute fields in a model

I made a model, which works like this: from a polygon, it extract its edges coordinates, turns it into lines and add an extra line.shp who will store the distance between the points. Because my ...
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1answer
49 views

Workaround for Mean Coordinates in graphical modeler

I am searching for a workaround to build mean coordinates in graphical modeler since I have noticed a bug which I have reported here: https://github.com/qgis/QGIS/issues/35385 Basically, I just need ...

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