When I use QGIS Dissolve geoalgorithm as a standalone tool from the Processing Toolbox, the GUI looks like shown below. By selecting the Input layer
I am able to chose from its attributes on wich to dissolve.
NOTE that the Input layer
is an output of another geoprocessing algorithm, in this case Intersection. This takes two input layers and combines the attributes of them. In the Dissolve algorithm I need to select one (key)attribute of each of this input layers:
Now I would like to combine Intersection and Dissolve in the Graphical Modeler, sth. like
... but I struggle with the configuration of the Dissolve alg. Herein its GUI looks slightly different:
Intuitivly I would guess that the dropdown Unique ID fields
should by populated with the attribute names of the selected Input layer
in order to select the desired attributes to dissolve on, but it doesn't (wich is
clear at a second look, because during creating the model the input attributes are unknown since input layers are not yet selected)
Therefore I tried entering a comma separated list of the attribute names (prior known to me, here id
, name
), but this is causing an error
Error executing algorithm Dissolve 'NoneType' object has no attribute 'split' See log for more details
...wich usually happens with unchecked Dissolve all
and no attributes provided.
Question: How to select the attributes to dissolve on when using Dissolve algorithm in Modeler with another algorithms output as input? Am I missing something or am I using this in an inappropriate way or is this worth raising an issue?
Table multiple field
input parameter and connect it to theDissolve
algorithm. You should be able to select fields when you run the model.