In PostGSI, is there anyway to turn a GEOMETRYCOLLECTION into a MULTIPOLYGON by dropping all non-POLYGONs/non-MULTIPOLYGONs?
I'm doing a query that cuts a bunch of geometries (using
ST_Intersection) and I want to group them together. I'm using
ST_Collect to turn this into a GEOMETRYCOLLECTION. I could use
ST_Union, but that's slower. Is there an alternative approach where I can drop all the non-POLYGONs/non-MULTIPOLYGONs from a GEOMETRY collection and just return a MULTIPOLYGON?
I know would be less accurate than
ST_Union, but it should be faster. For what I'm doing a small hit in accuracy is worth it if it speeds it up.