GeoChange: an experiment in wide-area database services for geographic information exchange

The GeoChange project is investigating a distributed database management architecture and services to facilitate the perusal, selection, and retrieval of multiple, third-party geographic information sources (GIS) across wide area networks, such as the Internet. The system uses a quasi-dynamic approach to information exchange which combines loose coupling of the source systems with distributed database management support services to improve the speed and reliability of retrieval. Application developers can use the system for ad-hoc merging of information from diverse GIS sources. Filters and integrity constraints managed as metadata bring further efficiency to the information exchange process. This paper is an introduction to the GeoChange system architecture and its operation. A protoype implementation using real geographic databases provided by the Hong Kong GIS community is near completion.