A spatial data model underlying human interaction with object-oriented spatial databases

In geographic maps, objects are represented in a context extremely rich of relationships among them, either one-to-one or many-to-many. Unfortunately, all these relationships can not be directly represented in the database scheme. Nevertheless, it should be possible to show them to the user during the interaction. To manage this problem, the authors refer to a two-level database architecture with an object-oriented data model at the bottom level (the logic level), and an interaction model at the top level. The spatial data model given is an essential part of the interaction model. The spatial data model is a conceptual tool that enhances the object-oriented model with spatial relationships between objects. The basic objectives of the spatial data model are outlined: to point out the relationships among objects to be shown in the views, to define data structures suitable for navigating among database objects, and to provide a simple and powerful calculus for posing spatial queries against the database