Data-Base Management System Technology and Geographic Information Systems

Current operational data-base management system technology is restrictive in its capacity to clearly model and efficiently manage complex data objects, in general, and spatial data objects, such as those handled by geographic information system (GIS) software, in particular. This has led to the prevalence of hybrid GIS software architectures, in which the lexical and geometric components of spatial data are managed in a disintegrated fashion. However, recent developments in object-oriented DBMS technology suggest approaches for the unified management of spatial data. The need for distributed management of spatial data poses further technological challenges. Structure transfer protocols must be further developed to support real-time interchanges of subsets of spatial database on a query-by-query basis. Distributed crash recovery, concurrency control, and multiple copy updated capabilities as developed for distributed relational data bases must also be provided for distributed object-oriented data bases. Also, the technology to support physical and semantic integration needs to be further developed to allow distributed GISs to be built from pre-existing single-site components.