Research on the Integration of GIS-Based Digital Valley System

Geographic information systems (GIS) have become increasingly valuable tools in hydrology & hydrodynamic modeling and have been used in the evaluation of integrative development and utilization of water resource in many ways. These may relate to the coupling of hydrology & hydrodynamic models and GIS system, collaborative work of heterogenous systems and the integration of distributed spatial database. Typically these data and the processes have been undertaken on separate platforms, and this paper describes the development of such a system combining GIS-based modeling of hydro logical analysis and cascade hydroelectric station optional dispatching. Specifically it reports the framework, system design, function design, correlative techniques for GIS-based modeling and analysis in digital valley system integration. A three-tier architecture was introduced as framework in the system integration process, spatial database middleware ArcSDE integrate with Oracle to realize the integrative management of spatial and property database, a COM-based GIS component MapObjects was used for the GIS client-tier development, and different specific models are developed as COM-based component, The integrated system realizes both GIS and specific functions in hydrological analysis and cascade hydroelectric station optional dispatching, the function and data integration are both realized in some degree. This integrated system, not only realizes the basic GIS functions such as space query, statistics and analysis, but also supplies a tool for visualization of the hydrology & hydrodynamic analysis and simulation result. Furthermore, the COM-based framework makes it convenient to extend system function flexible by developing new specific models as a component