An object-oriented system for building and maintaining a spatial data structure
for use in topological applications. The data is organized in a database which
incorporates spatial feature location, attributes, and metadata information in
a relational framework across a hierarchy. The system provides for the instantiation
of the objects and levels that make up the database and for spatially indexing
the data among the objects across hierarchical levels. The data can be updated
while preserving the spatial linking among objects and levels, and the data can
be exported to a relational vector product format database.