An Active, Object-oriented Mediator-based Framework for the Development of Gis Applications

Most current geographic information systems assume and present the static world. But, new generations of GIS applications have much more demands in comparison to possibilities, which could provide traditional database management systems. Information that exists in the spatial database may be updated over time. Also, the very important demand is time capability to answer to state changing in database. The goals of our research activities are defining an active architecture, identifying the need for mediators in GIS, adding the active rules to the GinisNT spatial database and realize the active mediator level which perform active behaviour of the GinisNT. Paper describes how complete active database semantics can be supported on an existing framework by adding a mediator between the GinisNT spatial database and the client applications. ECA rules are fully supported through the ActiveMediator component without changing applications or the spatial database schema. The Active Mediator prototype provides integration of active and object-oriented features in one system. To provide support for temporal GIS application design and implementation, a suite of spatio-temporal object modelling and management technologies and tools has been developed constituting spatio-temporal object modelling and management system. The openness and scalability of developed frameworks enable their further improvement and refinement to satisfy the needs of specific, temporal GIS applications. Active, temporal GIS would improve understanding of the dynamic geographic processes caused by man, the nature or both, provide methods for detecting and analyzing trends and cycles in geographic phenomena, an would enable prediction of the future geographic states.