| With the development of internet technology, the architecture of the spatial information system become distributing. Web-based GIS emerge as application requirement of the GIS, such as WebGIS.At present,most web-based GIS has realized the rebuilt on represent layer for adapting web situation, but application logical layer and data layer are still concentric. With the development of the spatial information acquisition technology and management pattern, the application problem of integrating distributed spatial data and spatial analysis function can not be obviated.For the problem of integrating distributed spatial data based on web situation, this paper evolves the following research:We first introduce the development and application technology for GIS and WebGIS, we then discuss the technology and characters for distributed database and data integration, we present the management technology for spatial data at last. We emphases research the distributed spatial data integration technology based on WebGIS and the solution method for distributed spatial data integration based on Mediator/Wrapper architecture. Based on above, the basic design conception and system architecture for the ShangHai urban spatial application service system is given and the key issue and the corporation of work flow among modules inside the system are discussed in detail. At the same time, we present a dual- cache mechanism and management strategy based on WebGIS. We also research distributed query optimize technology based on idea of the parallel processing and discuss dynamic load-balance strategy combing the resource status monitor service. We research spatial data scale selectivity and realize restriction mechanism with different scale in web situation. A dynamic legend visualization and image data integration visualization has been realized.The proposed methods and strategies in this dissertation have been preliminary applied in ShangHai urban spatial application service system. |
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