[Qgis-user] Rendering shared exterior boundaries of adjacent polygon features

[Tim Malloy]

Fellow QGIS Users -

I'm trying to determine if its possible to have QGIS render the exterior boundary of polygon features only once when that boundary is shared with an adjacent feature (don't render overlapping exterior boundaries for both polygon features).  The data I'm working with is a county parcels layer and the symbology I'm using for this layer is a cross hatched line fill with a separate component for the outline of the polygons.  I've tried a couple of expressions (examples below) including one geometry generator and one data defined override for the stroke width of the boundary line but none of them achieves my objective.  I'm using QGIS 3.34.7 and my coding skills are limited.  I feel like I've seen this issue covered somewhere but have been unable to find a solution after extensive online exploration.

Method #1:  "boundary( difference( $geometry, aggregate( 'union', 'intersects', $geometry, other_layer := @layer)))"  This expression was used on the outline component of the symbology described above.

Method #2:  "CASE WHEN intersects( $geometry, geom_to_wkt( boundary( $geometry ))) THEN 0  ELSE 1 END"  Here I switched to using an expression on the stroke width of a simple fill, but I got an error message saying "Cannot convert to geometry".

Any input would be greatly appreciated.

Tim


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