Heterogeneous geographic databases contain multiple "copies" of the same objects at different levels of spatial resolution (or scale). Such multiple-resolution databases will only be useful if the different representations are consistent with each other. We have chosen a method that formalizes the semantics of geographic data. This approach leads directly to constraint checks of the validity of large geographic databases. The concepts of homeomorphism and similarity for spatial objects and spatial relations, in combination with the formalism of the 4-intersection, provide a framework for a systematic assessment of spatial consistency. Within this framework, we will develop formal models for assessing topological changes and identify which topological properties may be changed and which have to be preserved within consistent multiple-representation geographic databases. We will develop software prototypes to demonstrate the validity of our approach.
Last updated on May 9, 1997.
[ Geographic Databases | Spatial Database Research Group | NCGIA Maine ]