Stack Exchange Network

Stack Exchange network consists of 175 Q&A communities including Stack Overflow, the largest, most trusted online community for developers to learn, share their knowledge, and build their careers.

Visit Stack Exchange

Questions tagged [qgis-modeler]

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

1
vote
0answers
17 views

Is it possible to insert a string without ' ' in the modeler?

QGIS 3.4.7 I have a lot of Models where there are some string inputs. In all of them, I have to enter the string between quotation marks ''. I understand the meaning and pourpose of them in any ...
1
vote
0answers
25 views

Open attribute table script in QGIS 3.6 graphical modeler

I am looking for a script which will allow me to open an attribute table of the final output of a graphical model in QGIS. I know that you can use the following lines of code in the console but ...
2
votes
0answers
16 views

Merge Vectorfile Outputs from Model Batchprocess in QGIS

I have written a model in QGIS 3.6 that allows to vectorize the outlines of raster layers containing measurement data. I run this model as a batch process to vectorize several field outlines in one go....
1
vote
1answer
31 views

Define multiple fields to copy in graphical modeler in QGIS 3.6

I am looking to find the correct syntax for copying a defined set of fields when using the "Join attributes by field value tool" in the graphical modeler in QGIS 3.6. I would like to know how the ...
2
votes
1answer
47 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 ...
1
vote
1answer
28 views

Using fixed vector layer parameter in QGIS?

How can I set my input layers to be called as defaults is QGIS Modeller? I am sure I am missing something simple but as it is I need to pull them down from the list every time. I want to set them as ...
0
votes
0answers
30 views

Using relative path in QGIS 3.x processing modeler? [duplicate]

I try to use a relative path for the algorithm "Set style for vector layer" in the processing modeler, but it works only with absolute path. A similar request is here, but the answer doesn't suit me. ...
1
vote
0answers
40 views

Selecting polygon as Input in QGIS Modeler?

I need to create a model where I select two polygon and the first one is clipped with the second one. Difference function is doing it. But asks for two input layers. How can I add as Input a Polygon ...
0
votes
0answers
26 views

How to import xyz data in QGIS 3.0 Processing Modeler for creating points and raster?

I want use dsm data in QGIS 3.0 Processing Modeler. This data are in xyz-format. I want to convert xyz data into points to create a raster. Later I want also apply this modle for the a folder with ...
3
votes
0answers
30 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
48 views

QGIS: Graphical Modeler (Python?) task

I'm a complete newb when it comes to things like Python, however I'm keen to learn more. I have some experience with ArcMap's Model Builder and have started playing around with QGIS Graphical Modeler (...
1
vote
0answers
38 views

Create buffer based on the size of a line's length (QGIS) [closed]

I need to create a buffer around a point, witch has to be 1.3x bigger than the length of a given line. I want to automate this process with graphical modeler or pyqgis. So the program should ...
2
votes
1answer
35 views

How to change the Help Description in Modeler?

I´ve created some Models in QGIS 2.18 and the help in the Model shows only what is in the description field. Thats the way I want it. But I migrated to QGIS 3.4, and now when I type something in the ...
4
votes
0answers
42 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 ...
1
vote
0answers
34 views

QGIS Modeler - Select by expression error

QGIS Modeler works fine with my data if I store the layers as temporary layers, but soon as I will save the output in the selected folder (as shapefile or geopackage) I get a wrong result. The select ...
1
vote
0answers
31 views

Modeler with optional inputs or none?

I have a need for a model that all the input may be optional and allow the "Selected features only" option. So, I developed a model that fakes it all as seen in the example below I realize that some ...
2
votes
0answers
64 views

Method in QGIS to do a select by radius but ignore “islands”

I am looking for a process in QGIS to run a selection from a given point based of a radius that ignores "islands". For example you may have a body of water which acts as a natural barrier past which I ...
1
vote
1answer
50 views

Getting QGIS Model Processing Raster Calculator Error?

I am using "raster calculator" tool of the saga in my model. The tool correctly executes raster operation like "a * 2" in value formula option but the same expression is not executed pre-calculated ...
4
votes
0answers
59 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 ...
1
vote
1answer
52 views

Batch processing not available in Graphical Modeller QGIS

I'm currently running QGIS 3.6. I'm trying to set up a model that uses the GDAL 'Clip Raster by Mask' tool to extract individual rasters from a DEM. I'm using geopackage polygons as the mask layer. I ...
1
vote
1answer
26 views

Error with categorized render tool in model builder QGIS 3.4.3

In my model, I'm trying to color my polygon layer using an xml file through categorized render tool (under cartography toolset). However, when I run the model the output file has the attribute data ...
2
votes
0answers
102 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
2answers
49 views

Error when using vector field parameter in field calculator with graphical modeler in QGIS 3

When trying to divide a vector field parameter with an output calculated during the model process I get a No root node, parsing failed! error at the point in which the field calculator in the model ...
2
votes
0answers
15 views

Error in Graphical Modeler when converting raster to vector

I'm building a model where, among other things, I use r.watershed, from which I only keep the "stream segments" output. In addition I would like to convert that raster to vector lines. When I do that ...
2
votes
1answer
62 views

Converting QGIS Algorithm from history to a plugin / tool

Rather than going through the process of creating a plugin is there a way to take algorithms from the history and put them together to create a quick tool like in ArcMap? For example I have ...
1
vote
1answer
33 views

Filter options are not saving in Dissolve algorithm window through Graphical modeler in QGIS 2

I am working on my project in QGIS 2.18 through Graphical modeller and using some basic algorithms for polyline objects. However, I do not understand why specification for Dissolve algorithm cannot ...
6
votes
1answer
140 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 ...
3
votes
1answer
110 views

Modeling iterative processes in QGIS 3

In the QGIS version 2.X, there was an Iterative Button from the algorithm also available for the algorithm used inside the processing modeller. Actually, I use version 3.2 and 3.4 and can not find it....
4
votes
1answer
108 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
3answers
104 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 ...
0
votes
0answers
22 views

Making QGIS model that iteratively creates several constant grids at once?

I'm looking to calculate the volume of a virtual reservoir from a DEM. I would use a constant grid (SAGA) to represent the ceiling, and I want to see the change in volume for each 1 metre interval. So ...
1
vote
0answers
37 views

Unable to select table in “reclassify by table” algorithm in QGIS Processing Modeler

In the Processing Modeler (Graphical Modeler) for QGIS 3.4.3, the "reclassify by table" tool seems bugged. I cannot select a Reclassification table, even though it's an obligatory field. Am I doing ...
0
votes
0answers
56 views

Download OSM data with QuickOSM and QGIS Modeler example and/or tutorial to share

I would like to automatically search and save my results (11 layers) via the QuickOSM plugin using the Qgis Graphical Modeler. Could anyone help me with some already prepared example or some tutorial ...
1
vote
1answer
79 views

Inputting CSV in QGIS graphical modeler and defining its geometry [duplicate]

Is it possible to have a model in QGIS graphical modeller which accepts a CSV with geometry fields and then allows you to use them for the rest of the model as if it was a vector file? This is ...
1
vote
0answers
34 views

Way of viewing attribute table of layer at end of model without loading layer in QGIS

I have created a model in QGIS 3 graphical modeler, with the final output being a shapefile. I was wondering if it is possible to have the final result as a pop up of the data table just to view the ...
1
vote
1answer
117 views

How to extend QGIS Graphical Modeler with Python Scripts

I'm trying to extract lat longs from my centroids, then feed the lat longs to the Google distance matrix API using another python script. I exported the graphical model as a python script: ##Drive ...
2
votes
0answers
41 views

In QGIS 3 Graphical Modeler can you add a check box to allow for different model path

In the Graphical Modeler in QGIS 3 is it possible to add a check box to the model GUI that if selected takes you down a different path of the tree so to speak. Example: Within a model I want to have ...
2
votes
1answer
74 views

Change attribute table value using graphical modeler?

So I have a buffer layer with an associated attribute table. This table has a column called "value" that I want to change to "x" based on previous selection. I can select the buffers in the layers I ...
2
votes
1answer
204 views

How to open GPKG layer fo processing in QGIS

I am making a model with QGIS 3.4 graphical modeler that should open and process a layer from the GPKG located in the project folder. Since the folder path may be changed, and QGIS does not allow ...
1
vote
2answers
91 views

Listing multiple fields to be dropped at once in QGIS modeler?

I'm trying to drop more than one fields at once in QGIS 3 modeler on Microsoft Windows. I'm using the algorithm "Drop field(s)". What is the good syntax to list multiple fields to be dropped? Not ...
1
vote
0answers
22 views

Pass additional options to GDAL in QGIS v3

I'm using gdalwarp inside a QGis v3 model (using qgismodeler) and I'd like to pass the -tap option to the command. I can't find where to place this. Is it possible to add additional options to gdal ...
0
votes
1answer
46 views

Using fixed QGIS modeler vector input parameter?

I'm writing a QGIS (v3) model and I'd like to have a vector layer input fixed to a specific shapefile. This way, every time I run the model, I don't need to select the file. Is this possible? Right ...
1
vote
1answer
40 views

How do you delete an object or polygon that has been selected in a layer using the graphical modeler?

I wish to create a model in QGIS 3, that can delete a specific polygon that has been selected in a layer. Is it possible to do this? I go through a few different locations in a day and I don't wish to ...
1
vote
0answers
37 views

Summarize table by group and add logic to keep data

I need to dissolve a polygon layer by group but, at the same time, I need to keep some of the data in extra columns. This is the diagram: This is the logic for the new group: Cod = "Cod" where N1 ...
0
votes
2answers
116 views

How to run the graphic modeler from the python console in QGIS? [closed]

How can I run the graphic modeler from the python console in QGIS?
1
vote
0answers
43 views

QGIS problem using join by location algorithm

I am new to QGIS. I have a problem when i use the algorithm "Join by location" in my graphical modeler, it returns me the "uknown error". I think the problem is that the shape i´m using to join is ...
5
votes
3answers
90 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 ...
3
votes
1answer
98 views

File naming iteration QGIS modeler

I am attempting my first use of the modeler from the Graphical Modeler from the Processing menu in QGIS. I made a simple model for cliping species data by sanctuary.It has two Vector Inputs, uses some ...
2
votes
1answer
357 views

Exporting model to Python script using QGIS? [duplicate]

I want to edit a few things to my model in QGIS 3.2.2, but first I need to convert this model to Python script. Is there a way to do it?
1
vote
1answer
237 views

Access string output of QGIS 3 processing script in graphical modeler

In the good ould days of QGIS 2 I created a processing script, that takes as input a table and a table field (table has only one record) and returns the string attribute value of the table field: ##...