Evaluating Inconsistencies Among Multiple Representations *

If Geographic Information Systems (GISs) contain multiple representations of the same geographic objects at different levels of detail, it becomes necessary to compare the different representations and assess whether they contradict each other or not. Topological information is generally considered first-class geographic information and as such the preservation of topological relations among objects in different representations manifests a critical criterion for the comparison of multiple representations and their consistency evaluation. This paper describes a framework within which the topological consistency of multiple representations can be assessed. The rational for assessing topological similarity is the monotonicity assumption of a generalization, under which the topology of any object and any topological relation between objects must stay the same through consecutive representation levels; or continuously decrease in complexity and detail. Such changes are assessed through object similarity and relation similarity, respectively. Within this framework, only those topological invariants can be changed that are at least on an ordinal scale.