I just had a situation where ST_Equals failed to compare GeometryCollections. Looking add the source this is normal behavior, but there is no mention of it in the docs of ST_Equals.
This pull request adds a section to the documentation.
add note to ST_Equals that the function does not support geometry col…
@robe2 can you look at this ?
The problem is deeper than just ST_Equals. See http://lists.osgeo.org/pipermail/postgis-devel/2015-April/024827.html
If you have a homogeneous geometry collection, e.g. from ST_Polygonize, then use ST_CollectionExtract(geom, 3) to get a MultiPolygon, which works with ST_Equals and other relate functions.
@nmandery are you planning to provide better wording for the manual about this ?
It's basically that geometrycollection with proper topology work while those with ambiguous one would not. A workaround is to pass them through ST_UnaryUnion beforehand.
OK at https://trac.osgeo.org/postgis/changeset/14693/
Add note per #14
git-svn-id: http://svn.osgeo.org/postgis/trunk@14693 b70326c6-7e19-0410-871a-916f4a2858ee