An object-oriented geographic information system shell

Geographic information systems (GISs) are required to support a wide range of applications, many of which involve vast quantities of geographic data and a variety of data types, which include vector-form and raster-form spatial data as well as non-spatial data. However, melting vector and raster data and expressing the natural associations between the spatial data and non-spatial data in a GIS cannot be conveniently managed by the traditional record-based system. A system based on an object-oriented paradigm seems to be an appropriate candidate for effectively managing these data since the object-oriented paradigm provides a basic and flexible modeling concept, object, and different modeling mechanisms, such as abstraction, encapsulation, and inheritance, to facilitate the representation and management of diverse geographic data. Thus, spatial data and its relevant non-spatial data as well as the manipulations on them are tied together and represented by an object, which is the basic construction unit of a GIS application. In such a way, the underlying functions and structures of a GIS can be constructed by organizing objects to form a GIS shell, which is the kernel of a GIS. The design of an object-oriented GIS shell based on notations given by the Object Modeling Technique (OMT) is described in this paper. In addition, features provided by the GIS shell are also discussed.