MULTIPOINT(EMPTY) MULTILINESTRING(EMPTY) MULTIPOLYGON(EMPTY) GEOMETRYCOLLECTION(EMPTY) These are [almost] fully integrated into PostGIS now. + WKT in/out + WKB in/out + GEOS conversion in/out + Indexable + collect() There are a few "weird" cases I need to look at before they're fully integrated. These were added for compliance with the OGC spec. dave