= Topo Geometry = A '''!TopoGeometry''' is a PostGIS type used to represent geometries defined by topological elements (face, edge, node,!TopoGeometry). Current code implements the !TopoGeometry using a class defined under the topology schema (`topology.TopoGeometry`). This has the following fields: * `topology_id integer` * `layer_id integer` * `id integer` * `type integer` The actual _definition_ of each !TopoGeometry is contained in the [wiki:TopologyTableRelation relation] table of the topology identified by `topology_id`. The "relation" table contains a record for each component of each !TopoGeometry. Interpretation of the component also requires looking at the [wiki:TopologyTableLayer topology.layer] table, which tells if element type refers to primitive type (node, edge, face) or another layer (in case of hierarchical !TopoGeometry). See [wiki:UsersWikiCreatingTopoGeometryObjects CreatingTopoGeometryObjects] for information on how to create a !TopoGeometry. See [wiki:UsersWikiPostgisTopology PostgisTopology].