Modeling Spatial Objects with Undetermined Boundaries Using the Realm/ROSE Approach1

The purposes of this paper are twofold, namely first to present general criteria for the design of spatial data types that are necessary and valid for the modeling of spatial objects regardless whether we consider objects with sharp or undetermined boundaries, and second to show how the concepts of a type system for spatial objects with sharp boundaries can be suitably transferred and extended to the modeling of spatial objects with undetermined boundaries. The most relevant design criteria of such a type system comprise generality, closure properties, rigorous definition, finite resolution, numerical robustness, topological correctness, geometric consistency, extensibility and data model independence of spatial data types. The Realm/ROSE approach allows for these design criteria and offers an appropriate definition of a type system for spatial objects with sharp boundaries. An extension of the Realm/ROSE model is proposed that shows how general region objects with undetermined boundaries can be derived from this model which have nice closure properties and which obey the design criteria. The idea is to consider determined zones surrounding the undetermined borders of the object and expressing its minimal and maximal extension.