The Research On The Theory Of WebGIS Distribution & Realization

As the next generation of global information infrastructure, digital earth has been widely accepted by our society. Currently, the development of information interoperability, object oriented software engineering and distributed computing technology provide firm basis for the building of WebGIS, one of the most important software platform for digital earth. This dissertation are researched and discussed systematically here, and designs and realizes the system of Publishment and Analysis of City Air Quality Based on WebGIS.Starting from the problem in the spatial data model of WebGIS nowdays, this paper analysizes and designs spatial data model , and builds a united spatial data model and oriented object expression. Then the distributed computing strategies of spatial information is discussed as a whole, the strategy together with the spatial object, spatial relationship, raster data is designed, realizes the distributed computing strategies and algorithm. MetaData is used to organize spatial information as a whole.In the following chapters, the interoperable model of WebGIS, multi-level B/S architecture, multi-thread for network computing and concurrent access, DCOM, intelligent agent, intelligent spatial search engine, information security are discussed in detail. With these key technologies, the system of Publishment and Analysis of City Air Quality Based on WebGIS is designed and implemented. This system makes people fell convenient in looking for data, try my best to our environment protection.The following problems and related solutions are given in this paper: data structure suitable for Web computing Multi-user access and concurrent control mechanism in WebGIS Network protocol and intelligent information agent of spatial information Spatial information security in Web computing environment Web integration strategy of spatial information based on MetaData Architecture of WebGISAt last, the development trend of WebGIS is discussed.