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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 "statically" by referencing the target layer as a vector layer named edges_only_carriageways added to the QGIS project before running the model.

"highway" = 'service' AND  overlay_touches('edges_only_carriageways_1eba8a9a_f253_4637_9914_88086f4e954d')

However, I want to turn this into a dynamic version by referencing the output of a previous algorithm from the model that holds the same features and attributes as the static layer from the above example. The algorithm is called non-foot carriageways. I added this algorithm as a dependency to the new algorithm. Then my approach was to do it like this:

"highway" = 'service' AND  overlay_touches(@non-foot_carriageways__OUTPUT)

But this does not work. No features are being extracted.

If I am on the wrong track, what is the solution for referencing the temporary output features from a previous algorithm of the graphical model?

PolyGeo
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winnewoerp
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    This is currently not possible: https://gis.stackexchange.com/a/379831/107424 – MrXsquared Oct 01 '23 at 07:39
  • OK, thanks for the clear answer. So no chance here to create a fully dynamic graphical model, right? Would a processing script be a good alternative solution where I dynamically create the necessary layer to access it within the expression in the respective following processing step? Or is there a simpler way? – winnewoerp Oct 01 '23 at 07:53

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