nest_id: The recursion level (if feature is a geometry collection)
part_id: The part index (if nested within a multi-geometry or collection)
type_id: The type identifier (see wk_geometry_type())
size: For points and linestrings the number of points, for polygons
the number of rings, and for mutlti-geometries and collection types,
the number of child geometries.
srid: The spatial reference identifier as an integer