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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1answer
19 views

QGIS modeler: downloading files with file paths informed by attribute information

I am looking to download files that are saved in a server location with a file path that is informed by attribute information created in the graphical modeler. The information that I would like to ...
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0answers
26 views

QGIS3 run model with python script

I want to run a model with a python script, including the parameters, because I can't "translate" the model easily into a script. I have tried to run a copy of the processing log after running the ...
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11 views

Loading rasters from a GeoPackage into QGIS modeler based on attribute information?

I am looking to load raster layers from a GeoPackage based on strings of attribute information that is stored in a field. The process I am looking for is as follows: Site Boundary created before the ...
4
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1answer
44 views

Using variable in graphical modeler for raster calculation? (QGIS 3.8)

I am trying to create a flow in the graphical modeler using a variable in a raster calculation. Is there a way to use a variable directly in the raster calculator (SAGA or GDAL)? I know there was a ...
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0answers
31 views

Save Selected Features in QGIS 3.4 Model

I'm trying to build some models I have in QGIS 2.18. Each model uses the "Save Selected Features" geoalgorithm so that the model only runs on selected features in the source vector layer. In 3.4 ...
2
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1answer
40 views

Python error when batching a Graphical Modeler script [QGIS 3.4.9]

I have a very simple Model to convert a table in points and to extract some features by their attributes. I can run it without any problem, except if I do it as a batching process. I received this ...
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1answer
34 views

Writing comments in QGIS Graphical Modeler?

Is it possible to write comments in the Graphical Modeler (QGis) ? I want to explain my model step by step so anyone can easely understand what's going on.
2
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1answer
88 views

QGIS 3.8 model to Python script, not working in 3.4

I am using QGIS 3.4 but it does not have the option of saving a model to a Python script. So I installed QGIS 3.8, which has that option, loaded my model and saved it as a Python script. I loaded the ...
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0answers
16 views

QGIS 3.4 Modeler gives error on non-required parameter?

I created a model which is asking to input 20 OPTIONAL parameters for vector layers. But when the user does not enter a value for any of the 20 parameters, QGIS returns an error. Traceback (most ...
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0answers
19 views

Ability in QGIS modeler to just run a step or subsequent steps in a model

In the current QGIS LTR is it possible to just run one step or all subsequent steps in a model if the previous steps have all been run and are not changed? Sometimes steps take hours to run so if ...
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0answers
28 views

When using QGIS Modeler with geopackages is there any way to Extract one Specific layer when using clip function?

I would like to use QGIS modeler to allow extraction of certain layers of a geopackage. I am trying to clip a geopackage containing multiple layers using modeler and when run it the output gives only ...
3
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1answer
46 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 ...
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1answer
19 views

qgis:deletecolumn in QGIS 3 graphical modeler

I want to use the algorithm qgis:deletecolumn in a graphical modeler. How do I have to fill the case Fields to delete : ["field1","field2"] "field1","field2" field1,field2 [field1,field2] And is ...
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0answers
20 views

Copy all features and attributes to a new dataset based on a template in QGIS Modeler

In QGIS desktop I can merge a template spatial file that has no data but all the attributes I need with another spatial file that has the spatial data where some of the attributes aren't in the ...
2
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1answer
35 views

Compare two columns using Graphical Modeler in QGIS

I have a layer with several columns. One of them is called 'cod' and the other is called 'cod_2'. 'cod_2' is null, except for one row. I want to know if the numerical value of 'cod_2' is present in ...
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0answers
16 views

Including metadata on QGIS 3 models?

Models on QGIS 3 are stored following a XML schema. Do you know if it is possible to embed metadata, may be using Dulin Core or ISO? I have noted that the modeler's help take in account subjects like: ...
2
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1answer
25 views

QGIS 3.4 Modeler: Select a band of a raster layer for processing

As model input data I select a raster stack with three bands. The first processing tool just needs specific bands of this stack which I like to select in the input dialog. I create a 'Raster Layer' ...
2
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1answer
35 views

Why QGIS3 is not running processing models and scripts in background?

I have a problem with QGIS 3.6.0 on macos and QGIS3.2.3 on Windows7 with running processing scripts and models in background. According to QGIS3 docs they are run in background thread by default (if ...
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1answer
92 views

Adding points along lines. Incorrect result. QGIS

I'm trying to add points along lines every 3 metres but I'd like the starting/ending point at certain non fixed distance. When I use the tool 'Points along geometry' inside Graphical Modeler. I don't ...
5
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1answer
114 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 ...
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1answer
23 views

How to enter text into attribute tables with QGIS graphical model?

I am using QGIS 2.14 to open NC files for chlorophyll satellite data with the end goal of compiling chlorophyll values for many dates (each its own initial file) in a spreadsheet. I know how to do the ...
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0answers
36 views

How to chain multiple field calculators in QGIS Modeler with pointers on next or previous feature?

I have a Model that I use to filter a chain of points that have extracted values form a DEM (digital elevation model). I want to smoothen the hights with a filter that takes the average of the ...
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0answers
57 views

Using input layer as output in PyQGIS for QGIS Modeler?

I have written a simple Processing script to rename a given field. It works successfully, changing the input layer's field name. However, I have not been able to produce an Output. This is a problem ...
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0answers
38 views

Python script from graphical modeller of QGIS 3.4 gives KeyError?

For several tasks in QGIS 3.4 I need a python script. As I am not used to use python I created the script with the graphical modeler (I modeled the tasks in the graphical modeler and exported the ...
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0answers
29 views

Inserting string without ' ' in QGIS 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 ...
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0answers
31 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
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0answers
20 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....
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1answer
43 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
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1answer
88 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
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1answer
34 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 ...
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0answers
31 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. ...
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0answers
44 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 ...
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0answers
51 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
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0answers
54 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
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1answer
54 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 (...
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41 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
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1answer
38 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 ...
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0answers
49 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 ...
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0answers
40 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 ...
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0answers
44 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
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0answers
68 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
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1answer
68 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
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0answers
70 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 ...
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1answer
84 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 ...
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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
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1answer
148 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 ...
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2answers
72 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
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0answers
19 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
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1answer
65 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
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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 ...