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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Adding iterative group of algorithms to QGIS model

In a QGIS model, I have a section in the workflow where a certain group of algorithms (let's say: do A, then B, then C, then D) has to be re-run until a condition is met. So depending on the input ...
Babel's user avatar
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QGIS model algorithm "Load layer into project" wont allow layer to be loaded more than once

I am creating a model which saves a polygon layer as geopackage in a project folder. I then want to load that layer into the project several times and apply different style files to each layer to show ...
Greengadget's user avatar
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Recursive model in QGIS

I needed to do an algorithm in the modeler and wanted to try (and also because I couldn't see any other solution) to make it recursive. Unfortunately, now every time I try to just open the model to ...
Biorix's user avatar
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Use output of an algorithms with another algorithm in QGIS Graphic Modeler [duplicate]

I have Processing Algorithm of Explode Lines and I need to use the output of the layer to create a field calculator Processing Algorithm, so i have entered the filed name that i need to create and ...
Abdullah Muthanna's user avatar
1 vote
1 answer
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Using QuickOSM in model designer QGIS

I am trying to create a model in QGIS using the model designer but having difficulties with the QuickOSM features. My goal is to: Create three buffers (2km, 3km, 6km) around a multi point feature. ...
GeoCharm's user avatar
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QGIS select by expression Modeler

I'm trying to build a model which should select polygons based on selected polylines. The polygons share attribute values with the polylines. In this case the field "Outlet" (polygon) ...
user237984's user avatar
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QGIS create vectorlayer based on project axis and data table

I have a project where I need to mark ongoing and planed projects along a river on a map. I have a list of the projects in form of a table with multiple attributes including the start and end point ...
Markus Lang's user avatar
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Linking Point input data with SAGA Upslope input in QGIS Modeler

I have a model set up with a point input. I need the point's x and y coordinate data to populate the x-value and y-value fields required as input for the SAGA upslope function. I have tried various ...
Louw's user avatar
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Picking Input Layer according to attribute string in QGIS Graphic Modeler

My model is based on a vector layer which contains a Field with layer names. The Plan is to pick the input raster (from a directory or directly from the project layers) according to an attribute value ...
farmgis's user avatar
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Using Python script inside QGIS Graphic Modeler

I created a model that combines two vector layers and outputs a single layer with aggregated data. I have a Python script that calculates the Chi-square, and I would like it to be executed at the end ...
Tony Sampaio's user avatar
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QGis-Modeler: Using "Basic statistic" values for "Extract by expression" - Outliers

I'm working on Qgis 3.34.0. with Model Designer. I'm working with soil data (Organic matter for example). I have 2 data sources, "cal OM" and "lab OM". The data I'll use will be &...
Matias Z's user avatar
3 votes
1 answer
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Grouping sum by user provided field name in graphical modeler

I want to sum and group some percentages as a part of a model in order to check whether the percentages are exactly 100, or if there is a small rounding error. When using the field calculator outside ...
Erik's user avatar
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How to update a field in a layer with the DBSCAN algorithm using the Graphic Modeler QGIS

As you can see in the screenshots, I have a vector layer 'POINT_LAYER' with an "IDCLUSTER" field ready to be updated. I am also using Graphic Modeler to prepare a processing workflow to ...
Acperience's user avatar
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2 votes
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Transferring QGIS Algorithm settings/properties to modeler

When creating models I often first run a toolchain step by step on a small example dataset to test whether each tool does what I want and if I get the desired result. I then use this to build a model, ...
Honeybear's user avatar
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Selecting polygon based on value present in field using QGIS Graphical modeler

I have a layer (polygons) of municipalities and I need to select just one polygon based on their name (e.g. 'venice' this value is present as a value in the field "COMUNE" ) because this ...
Checco68's user avatar
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Don't re-use previous model run's user inputs

I have a QGIS model with a Number input (though this applies to many if not all inputs) When users enter a number in the model's dialog, run the model and then re-open the model dialog to run it again,...
bugmenot123's user avatar
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QGIS: Model Designer: Specify the order in which algorithms are run

I am trying to build a complicated model in the model designer. It will have, once I'm done, probablyy around 20-30 conditional branches. The branches select and extract points from a point layer with ...
Andy Baader's user avatar
5 votes
1 answer
217 views

Using Conditional branch algorithm in QGIS Graphical Modeller

I have a question regarding using the Conditional Branch algorithm in the Graphical Model Builder. I am building a rather complicated model with many branches but not every branch needs to be used ...
Andy Baader's user avatar
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In QGIS modeler I get SQL query syntax error - in Database Manager SQL window is working fine

I have SQL query which add record to several related tables. When I run query in Database manager, it works fine. But when I use PostgreSQL execute SQL from algorithms in Model Designer, I get error. ...
Tomas's user avatar
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3 votes
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Creating dummy (random) vector layers of different geometry types, with random attributes

Problem In QGIS, one sometimes needs some layers with dummy data just to test something: the functionality of an expression, the syntax of an SQL query in a virtual layer, creting quickly an animation ...
Babel's user avatar
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1 vote
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Using QGIS Model Designer to rotate points but it moves the points location

Using model designer to automate a process and I would like to be able to rotate points whether it be using the affine transformation tool or the rotate tool. I have gotten both of these tools to ...
Max's user avatar
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3 votes
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106 views

Removing memory layers as you go in QGIS Graphical Model to avoid running out of memory

I run a lot of graphical models to automate the workflow of complex tasks. Often, my workflows have 40 or 50 steps that manipulate attributes in a complex way. The graphical modeller is powerful and I ...
Cameron Blackburn's user avatar
4 votes
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58 views

In QGIS, can the 'spatialite execute sql' algorithm accept '.sql' text files?

I'm working in Model Designer on a process which includes running an SQL on a SpatiaLite database. I have the connection as the input, but I want the SQL to come from a text file 'xxxx.sql'. ...
Isaac Braham's user avatar
1 vote
1 answer
33 views

Using Modeler to change attribute names to (self) set standard

I'm trying to use the Modeler to format a vector layer input with an attribute table to a new vector layer with the same attribute table, but where the column names are standardised. The point of this ...
Balb31's user avatar
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3 votes
2 answers
145 views

Graphical model for random points inside polygon moved to closest point on line

I want to place a regular random distribution points inside a polygon and move these points to the respective closest point on a line layer afterwards. I use regular points algorithm with random ...
winnewoerp's user avatar
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1 vote
1 answer
59 views

Dynamic point shifting based on bearing and elevation surface

I'm currently working on a graphical model (for planning centre pivot irrigation locations) that moves points iteratively based on a given span length, bearing and span number. All spans are initially ...
Beets's user avatar
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1 vote
1 answer
57 views

Find nearest points on network inside QGIS Graphical Modeler

I create a set of regular points with random offset inside a test area polygon using the QGIS Graphical Modeler. This it what the result looks like: Then I use the following expression (not yet very ...
winnewoerp's user avatar
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2 votes
1 answer
109 views

How can I merge two line layers correctly for network analysis in QGIS?

I have a graphical model in QGIS that takes a basic sidewalk network (derived from OpenStreetMap data where separate sidewalks geometry exists) and adds additional crossings automatically. As a last ...
winnewoerp's user avatar
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2 votes
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Combining data from one of the three tables when the condition

There are 3 tables. Need to attach one of them depending on the maximum value in the "VALUE" field of the calculated layer? I have problems with programming :) but still I tried (it didn't ...
Rudzik's user avatar
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Matching specific word character in QGIS Graphical Modeller

With the graphical modeller, I try to decode a set of codes: Since the code '_zie' is also contained in the code '_p_zie', I get two matches for '_p_zie'. How can I get two specific Word characters ...
Janko's user avatar
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27 views

Calling Toolbar's tool in to Graphical modeler in QGIS

I need to use the "Merge selected features" tool from "Advanced digitizing toolbar" in my QGIS model. I am not sure how to call tools.
MapQuest's user avatar
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2 votes
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33 views

Select by Expression in QGIS Graphical Modeler on pre-defined layer name

I'm trying to build a model using the graphical model designer. I have a conditional branch that loads a postgres layer depending on whether a "development" or "production" ...
SlightlyCultured's user avatar
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Parameter not respected in formula (in PyQGIS script exported from QGIS Processing model)

To demonstrate my issue with @parameters in formulas: I created a simple QGIS Processing model where an input_layer is buffered with buffer_distance. In addition the buffer_distance should be written ...
evod's user avatar
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35 views

Creating/choosing layer group in modeler using load layer in QGIS

Is there a workaround to be able to add the layer into a new or existing layer group? I opened an issue with a feature request with more details https://github.com/qgis/QGIS/issues/54895 I saw this ...
gotjosh's user avatar
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34 views

Adding algorithm parameters in QGIS Graphical Modeller initial dialog box

Can we have algorithm parameters in the Graphical Modellers initial dialog box. For example, if I use Extract By Location Algorithm, I can set parameters when editing the model but I cannot change ...
GforGIS's user avatar
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Accessing previous algorithm outputs in QGIS graphical modeler [duplicate]

I want to extract features by expression in a graphical model in QGIS. I want to use the overlay_touches() function to extract features that touch those of another layer. I manage to do this "...
winnewoerp's user avatar
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1 vote
1 answer
84 views

How to get multiple inputs for Extract selected features processing tool in model builder

First time using QGIS modeler so i'm not familiar with it. I want to select features from multiple layers (how many layers and what layers changes depending on the work) merge them into 1 layer (...
Mow's user avatar
  • 175
2 votes
2 answers
79 views

Merging polygons based on distance in QGIS

How can I merge not overlapping polygons? I'm trying to set up a model that merges polygons that are within 500m from each other, at the closest edge of the polygon. I have tried with the shortest ...
Endre Aaen's user avatar
1 vote
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19 views

Graphical Modeler_ Routing Calculation

I am trying to modify the QNEAT 3 plugin to make it calculate the least cost path, where the cost is not the "distance" ... I am using the "Expression" tool. Is there a simple way ...
Alaa Torkey's user avatar
2 votes
1 answer
36 views

Maximum width of screen in the QGIS modelbuilder

I am trying to make a model in the QGIS modelbuilder. The problem I am encountering is that my model is getting fairly wide. I have a lot more to put in under the base that is have now. The problem is ...
Simon's user avatar
  • 77
2 votes
1 answer
133 views

Change the style of the output of a model in QGIS

I have the output for a model in QGIS, but I want it to have a specific colour ramp. It is one of the default colour ramps offered in the Symbology menu for the Singleband Pseudocolour render type (It ...
Hareswar Nirmalan's user avatar
1 vote
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37 views

QGIS Graphical Modeler - Altitude offset / translation - Something wrong with my raster calculator (gdal) expression

I've recently started exploring QGIS' Graphical Modeler, and I want to build a model that will: Iterate over a vector layer's features Use these features as masks to extract from a raster Calculate ...
Qosa's user avatar
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79 views

Using Aggregate Expression in QGIS Graphical Modeller

I want to create a graphical model in QGIS. The model will input a polygon and a point layer and then add an attribute to the polygon that counts the number of points inside (intersects). I know that ...
Stat-R's user avatar
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2 votes
1 answer
85 views

Adding multiple fields to the same layer using QGIS graphic modeler?

I want to add multiple fields to my layer using the qgis graphic modeler. I am trying to do this with the field calculator, but I´m unable to add all the fields to the same layer. I always end up with ...
M0EWE's user avatar
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1 vote
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22 views

Splitting a point vector based on a date attribute within the QGIS Graphical Modeler

I have now a model which processes two layers of points corresponding to observations at 'Time_1' and 'Time_2'. It counts the observation per quadrats in a grid and obtains two outputs: a grid with ...
Sebastian Silva's user avatar
3 votes
1 answer
105 views

Calculating field with input from two layers in QGIS Graphical Modeler

Even though I found similar questions, I couldn't find a suitable answer for the problem I have. I want to create a model that calculates the difference between two fields ("NUMPOINTS") from ...
Sebastian Silva's user avatar
2 votes
1 answer
71 views

QGIS model designer save back into the same geopackage

I have a model that does some tidying of attributes in vector layers that are stored in a geopackage. The geopackage to work with is specified with a file path input (@survey_data_package) Therefore ...
Sethinacan's user avatar
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QGIS Distance to nearest hub wrong point selection for distance calulation

I'm using the graphical modeler in QGIS 3.28.8 to automatically calculate distances of two lines between points, see the picture. To do this, I'm using Distance to nearest hub (line to hub) and an ...
abedl's user avatar
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Compile two layers by new added points or updated attribute

I have two point layers: Layer A and layer B (which is the copy of Layer A), so they have same data at the beginning. Now I`d like to make some changes in layer B and sometimes add another point to ...
lesto's user avatar
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34 views

Adding temporary layers to a group in QGIS Graphical Modeller

Is it possible to add the temporary layers directly into a group ? Below example in the buffer algorithm's dialog.
GforGIS's user avatar
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