A SPATIAL DATA MODEL DESIGN FOR FEATURE-BASED GEOGRAPHICAL INFORMATION-SYSTEMS

In state-of-the-art GIS, geographical features are represented as geom etric objects with associated topological relations and classification attributes. Semantic relations and intrinsic interrelations of the fe atures themselves are generally neglected. In this paper, a feature-ba sed model that enhances the representation of geographical features is described. Features, as the fundamental depiction of geographical phe nomena, encompass both real world entities and digital representation. A feature-based object incorporates both topological relations among geometric elements and non-topological (semantic) relations among feat ures. The development of an object-oriented prototype feature-based GI S that supports relations between feature attributes and feature class es is described. Object-oriented concepts such as class inheritance an d polymorphism facilitate the development of feature-based GIS.