Spatial object modelling is a seasoned tool for use in GIS applications. Although a large body of conference and journal material exists, this is the first focused and integrated treatment of the many issues which contribute to the subject. It provides a background view of the object approach, related geometric aspects, the different level of data modelling and the role of geo-information theory. The book then builds upon these concepts and develops a formalism that can serve as a theoretic framework integrating (encompassing, combining, linking) aspects such as topology, thematic object classes and class hierarchies, object aggregation and generalisation and uncertainty.