A distributed object architecture for interoperable GIS

This paper presents a distributed object based multilevel architecture to allow interoperability among heterogeneous geographical information systems (GIS). It consists of a lower level which provides interconnectivity among information sites and a higher level which provides fonctionalities to hide the heterogeneity among GIS. 1 Introduction Geographical information systems manage georeferenced data. They are characterized by a large volume of data, by modeling of complex spatial relationship, and by the diversity of existing models. Interoperability of GIS is the ability to access spatial data and associated services in a distributed and heterogeneous processing environment. Interoperability is necessary for the following reasons: 1) data are costly, 2) applications are no longer built from scratch but are constructed from existing components and 3) GIS applications may require specifics functionalities that are not supported by all systems. Interoperability among traditional inform..