Geographic Information Systems

Questions tagged [qgis-modeler]

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

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QGIS Graphical Modeler: Raster calculations with iteration. CSV data import

Im using GIS 3.14.16. I am working with a raster layer and a table with n multipliers in CSV format (values are saved in 1 column, but could be also one row and n columns). I would like to create n ...
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13 views

Defining area for QuickOSM query in QGIS Modeler

I would like to use the QGIS Modeler to collect all objects of as OSM feature within polygons in a layer. The QuickOSM algorithm has a function called "build query inside an area" and I was ...
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1answer
67 views

How do I use Join Attribute by nearest in this case, to avoid referencing an algorithm output in field calculator expression?

I have a model that I have built to automate the process of assessing wind hazard on forested edges. Currently I can run it successfully but: I have to run it once, create the Test layer, and then ...
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1answer
40 views

Updating an existing field with field calculator in QGIS modeler

When incorporating the field calculator into the graphical modeler in QGIS is it possible to update an existing field without having to create a new field and then remove the existing. For example I ...
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1answer
30 views

Using vector field for buffer model in QGIS Modeler

I am creating a model that will create a viewshed and a buffer around an observer layer /point. I want to use a field in the observer layer for the buffer range. I tried the option 'Field type'. But ...
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1answer
48 views

XY coords for clicked point QGIS graphical modeller

I am trying to calculate a bearing from each point in a layer to a single target using the graphical modeller as its part of some other processing I need to do. I can do the bearing calculation (below)...
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8 views

Modeler - QNEAT3 - selected destinations instead of “all origins” to “all destinations”

I would like to calculate the distance between points from table A (80 000 entities) , to points from table B (500 entities), filtering with a relation parent-infant (or just using a common field ...
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1answer
49 views

Extract raster properties and use them in QGIS graphical model

I would like to generate a tool that reclassifies rasters in 10 classes with equal intervals. Since QGIS reclassifies tools does not allow to automatically create classes with such methods, I was ...
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26 views

Running QGIS 3.1 Graphical Modeler Script as standalone

I have troubles running a Graphical Modeler Script as standalone via the OSGeo4W Shell console. Everything works fine when I run the script in QGIS. When I open it via shell, nothing happens. I think ...
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1answer
34 views

QGIS Processing Modeler not showing algorithms anymore

I use QGIS 3.4 on Linux Mint 18.1 and have happily created models once I came to know about this awesome feature. But some days ago the algorithms disappeared. If I right click in processing modeler I ...
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50 views

Drawing a line with the same length as the layer extent in QGIS Modeler

How can I use the height of a polygon (layer extent) to construct a line slightly longer than the polygon? I’m in the Modeler and my input is s polygon layer. I will be constructing the line from a ...
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34 views

Constructing point at corner of layer extent using QGIS Modeler

I’m in the Modeler. My input is a polygon layer with a polygon (agricultural field) and a line layer with a line indicating a direction of travel within the field. The field will be filled with ...
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1answer
19 views

Converting a modeler 2.x to a 3.x - Done by hand

After reading here that's no easy way to convert a modeler in 2.18 to 3.10, (model to model3). I made my model3 by hand based on the model version 2 i had. After some problems with the OUTPUT files, i ...
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70 views

Load layers from SQLite database in Model Designer

Regularly, I have to load layers from SQLite databases through Spatialite in Qgis 3.16 and perform some algorithms. Extension of these SQLite databases is not *.sqlite but another format (proprietary)....
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1answer
55 views

Add all the shapefile in a map from a folder

I'd like to know how can I add, in the map, all the shapefile which are in a specific folder, in one shot; using an algorithm of the Graphical Modeler of QGIS (if it exists). I noticed a similar ...
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0answers
33 views

Unavailable algorithm in QGIS

When I try to launch my model (graphical modeler) in QGIS I get this message (in french) : Cet algorithme ne peut pas être lancé :-( Le modèle que vous essayez de lancer contient un algorithme qui n'...
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1answer
56 views

Assigning id from a polygon to new field in intersected points using the Graphical Modeler in QGIS

I’m working with the Field Calculator in the Graphical Modeler and I’m stuck. I need to assign the feature id from a polygon layer (track) to a point layer (StopPoint) so that I can group together ...
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25 views

Modeler - output of first algorithm not going to second one and so on

I've a model with subsequent steps of LAStools algorithms. Individually they work well, but in the modeler I get only the first output, and no more. It seems like the second algorithm is not taking ...
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2answers
112 views

Count number of features in a geopackage and write to a file

I'm tasked to create a simple catalogue of 2000+ geopackages, and hope there is a way to do that with QGIS. The idea is to batch run over all these geopackages and write the following to a CSV file; ...
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1answer
124 views

Opening old QGIS model in current QGIS versions

There is an older answer by @underdark to this post: Finding centrelines from polygons in QGIS? She links a QGIS model that apparently was created in QGIS 2.12. It has the file extension .model When I ...
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1answer
43 views

QGIS Processing modeler not showing toolbar

I've just installed QGIS recently (3.10.10 with GRASS 7.8.3) on a new computer. Previously, I used the same version and there's a toolbar in the Processing Modeler (to save and run model). But now, I ...
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1answer
37 views

Using Set Z Value in QGIS Graphical Modeler - Modeler not passing elevations from field

I am trying to use the Set Z Value algorithm in QGIS Graphical Modeler. More specifically, I would like to set the elevations using values contained in a field in the input layer, but the elevations ...
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43 views

MultiRing buffer plugin to Python script in QGIS

Is there a way to get the MultiRing buffer plugin into a Python script? I want to use it in the QGIS Modeler, but I cannot use plugins in there, or to get multiple buffers with varied (not equal) ...
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1answer
110 views

Using conditions in Graphical modeler QGIS 3.10.5

I have a question about my model which is quite complex. I have two types of line INPUT and the model will not be executed unless one of the line INPUT is empty. The problem is with a tool 'Snap ...
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1answer
66 views

Saving multiple raster sums to one Excel file on QGIS

I have a couple hundred raster files that I want to find the sum for in order to perform some further calculation. I want to have the sum of each raster file placed in one Excel sheet. I used to work ...
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3answers
168 views

Making polygon layers always have area fields in QGIS

I am making Delaunay triangles of several (over 40) combinations of points and it is very tedious to output new shapefiles for each combination without even having the area of the triangles by default,...
2
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1answer
46 views

QGIS - Translate group of polygons to centroid

Using QGIS Process Modeler, I need a way to create a grid that is centered on an input feature. My issue is that the [Create grid] algorithm, creates a grid whose upper left corner is aligned to the ...
3
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1answer
41 views

Field Calculator case sensitive issue in QGIS graphical modeler

I use QGIS 3.10 with the graphical modeler and I'm facing an issue while creating new field in field calculator: it seems to be case insensitive thus it does not create the field I want. Problem ...
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12 views

QGIS r.water.outlet multiple points processing modeler

I am trying to create a process with the process modeler. I want to run r.water.outlet by importing multiple points (a shapefile of points). I searched through the internet and StackExchange. Could ...
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2answers
164 views

Merging multiple lines by value field

How can I join these lines depending on the Trigger field. The condition is as follows, the fields must be ordered in ascending order after the fid field from 1 to 68. Thus, I want to join all my ...
2
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0answers
67 views

Specifying dependable layer names in QGIS Processing Modeller [closed]

I am creating a model in QGIS (3.10.3) Processing Modeller (Win 10[64]). Final Objective To create Voronoi polygons from centroids that are clipped to a higher, polygon, geometry. Hurdle The Voronoi ...
2
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1answer
75 views

QGIS Model Designer - Select by Attribute with Multiple Field Parameters

I am building a model that includes a 'select by attribute' algorithm, and I am attempting to select by multiple fields where the value matches a model input. Essentially, I want the selection query ...
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1answer
70 views

Filter (query) OSM .pbf file in QGIS graphical modeler or Python (QuickOSM or related tools)

I would like to automate a simple operation in the QGIS graphical modeler or a simple Python script. add all line features from a .pbf file filter all features with certain values within a certain ...
2
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1answer
121 views

Changing inputs in QGIS modeler

I'm new to using the modeler function in QGIS. I'm trying to follow the tutorial in the screenshot. But when I follow the steps it ends up with my in/out algorithm not connected to the "...
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0answers
67 views

How to use multiple field calculator in QGIS graphical modeler

I find myself struggling to understand how to chain field calculator process in the graphical modeler in QGIS. I have build a model that take 3 layers input and 3 vector field parameters and try to ...
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1answer
35 views

rscript in QGIS processing toolbox and Rstudio, results mismatch

I am using my own R scripts in QGIS. Before adapting them to work in QGIS, I write them in RStudio to make sure they work properly. I then use different scripts in a batch model. In RStudio I have ...
3
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1answer
178 views

Workflow automation QGIS - populating attribute table

Is there a tool in QGIS which populates fields within the attribute table? I know I can edit it manually but what I want is to include that tool in the workflow automation process. I want to label the ...
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0answers
28 views

Use model input to amend SQL Query in QGIS Modeler [duplicate]

Is there a way I can use a model input in QGIS modeler to amend the parameters of a SQL query. For example I want a model input (string) to allow me to pick the name of someone I am searching for in a ...
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1answer
36 views

What is the syntax for assigning a feature attribute value to a variable in the QGIS Advanced Python Field Calculator?

Using the QGIS Advanced Python Field Calculator, I am able to assign the new field a value from a feature an existing field using value = <Attribute_1>. I run into a problem when I am using ...
2
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1answer
36 views

Duplicating raster layer using QGIS Modeler

I have a repetitive process where I duplicate a raster layer twice so I have 3 instances and I can display hillshade, elevation, and contour styles - I'm trying to create a model to run this process ...
3
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1answer
121 views

QGIS: Use of a model output in the same model as a layer in the field calculator formula

I am trying to use field caluclator within a model. In this formula I want to reference the output (temporary layer) of another step of the same model (output objektfilter_strassen_wege, which is ...
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0answers
60 views

Set project variable to a field value when iterating over vector features with graphical modeler in QGIS 3

I have a Data layer containing features with some fields (e.g. rows with color and name). In the Graphical Modeler I want to iterate over the features and assign the field values to some project ...
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1answer
51 views

Where is my model? (saved in project, QGIS 3.10/3.16)

I saved a model (Graphical Modeler) into my project and I don't know where it was saved. How can I get it back?
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1answer
112 views

Store the filenames of .kml files into the attribute table of a shapefile

I have to be joining .kml files in a single shapefile. The problem is that the kml files comes with a name that when I convert it into a shapefile it is not kept in the attribute table. thus, I lose a ...
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0answers
39 views

Output layers order in QGIS Graphic Modeller (algorithm execution order / dependencies)

I created a simple model in QGIS graphic modeller that takes in input parameters like drive time ranges and start location and outputs 3 styled layers including "start_point", "...
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0answers
27 views

Layer fields refactoring does not work for CSV export file

In my graphical model does not working refactoring layer fields. Entry layer has two fields, which first is string and second is integer. My Refactoring functions change first column to int and second ...
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1answer
29 views

Model designer issue, QGIS 3.14 on iMAC

I tried to make Model in Model designer but I don't see my new fields in designer window, but only the offer of the existing layers. What's wrong and what did I miss? There is no connection lines.
4
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1answer
138 views

Processing tool to invert/switch selection in Graphical Modeler

I want to switch/invert a selection in Graphical Modeler so I'm looking for a processing tool to do so. In ArcGIS, this can be done with "Select Layer By Attribute" with Selection type: ...
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1answer
55 views

QGIS refactor field in processing modeler

I am trying to create a model to standardize data received from various clients into one single output format. To do so, I use the refactor field and field mapper, following the answer given here: How ...
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46 views

QGIS Model Designer; save layer in geopackage with date

I have used the model designer to make a model in QGIS. The model takes data different shapefiles, and runs a few algorithms. The result is different layers loaded in an new project. I manually store ...

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