Topological information are the most important kind of qualitative spatial
information. Current formalisms for the topological aspect of space focus on
the global relations between regions, while overlooking their internal
structure. Complex regions could be of multiple pieces and/or have holes and
islands to any finite level. We propose a layered graph model for representing
the internal structure of complex plane regions, where each node represents a
connected component of the interior or the exterior of a complex region. More
importantly, the model provides a complete representation in the sense that the
(global) topological relation between two complex regions can be determined by
the (local) topological relations between associated simple regions. Moreover,
this graph model has an inherent hierarchy which is exploited for map
generalization.