• ST_Geometry type

• ST_MultiCurve type
• ST_MultiPoint type
• ST_MultiSurface type

• ST_GeomCollection constructor

• ST_GeomCollectionAggr method for type ST_GeomCollection
• ST_GeometryN method for type ST_GeomCollection
• ST_NumGeometries method for type ST_GeomCollection
• All methods of ST_Geometry type can also be called on a ST_GeomCollection type.

An ST_GeomCollection is a collection of zero or more ST_Geometry values. All of the values are in the same spatial reference system as the collection value. The ST_GeomCollection type can contain a heterogeneous collection of objects (for example, points, lines, and polygons). Sub-types of ST_GeomCollection can be used to restrict the collection to certain geometry types.

The dimension of the geometry collection value is the largest dimension of its constituents.

A geometry collection is simple if all of the constituents are simple and no two constituent geometries intersect except possibly at their boundaries.