This is opened from the comments from @otan and @andyyang890 in #197.

@otan wrote:

i think in go-geom, we want to relax things we check in CockroachDB (subject to @twpayne guidance!) as go-geom takes a more "OGC spec" view of the world, namely:
a) geometrycollections can have mixed dimensions.
b) linestrings/polygons do not have to have 2/4 points respectively, and polygon rings don't have to be closed.
c) i think empty can be mixed willy nilly in MultiPoint.

we can choose to optionally allow these checks (but have them off by default). this should be done with options -- see how we did the EncodeOption for Marshal above. probably DecodeOptionRunPostGISCompatibilityChecks which enables all the checks we did above.

@andyyang890 replied:

a) geometrycollections can have mixed dimensions.

If the PostGIS compatibility option is not specified:

1. Should a GEOMETRYCOLLECTION{M, Z, ZM} be allowed to have geometries with different dimensions or does that only apply to GEOMETRYCOLLECTION?
2. Should the layout for a GEOMETRYCOLLECTION always be geom.NoLayout?
3. If the answer to 1 is no, should the layout of a *GeometryCollection be set if it is a GEOMETRYCOLLECTION{M, Z, ZM} or should it remain as geom.NoLayout?