TopoGeometry — A composite type representing a topologically defined geometry.
A composite type that refers to a topology geometry in a specific topology layer, having a specific type and a specific id. The elements of a TopoGeometry are the properties: topology_id, layer_id, id integer, type integer.
topology_id is an integer: Refers to a topology defined in the topology.topology table which defines the topology schema and srid.
layer_id is an integer: The layer_id in the layers table that the TopoGeometry belongs to. The combination of topology_id, layer_id provides a unique reference in the topology.layers table.
id is an integer: The id is the autogenerated sequence number that uniquely defines the topogeometry in the respective topology layer.
type integer between 1 - 4 that defines the geometry type: 1:[multi]point, 2:[multi]line, 3:[multi]poly, 4:collection
This section lists the automatic as well as explicit casts allowed for this data type