This paper describes a unified framework for the problems of modelling and processing spatial entities. We propose a general definition of spatial objects, and show that the different types of spatial data can be expressed as particular cases of this definition. Furthermore, we present a taxonomy for the various types of GIS operations, defined in terms of the properties of this definition. Our goal is to argue that GIS data types and operations can be defined based on a single formal notion, which encapsulates the GIS concepts of both continuous fields and discrete features, with important consequences for system and interface design, interoperabilty issues and language proposal.
Geographical Information Systems; Spatial Databases; Geographical Data Models
