The Design And Implementation Of WebGIS Based On Web Service

With the speedy development of Internet,GIS plateform has been based on Web gradually.WebGIS is the result that Internet and World Wide Web technology apply to GIS development.In Geographical Information system,The user,through each note of the Internet,can accomplish lots of operations to get much spatial information,including getting needed spatial data,Creating thematic maps,doing some spatial information retrieval and spatial analysis,The spatial data has a character of variable resource,semantic,spatio-temporal,scale and complicacy of obtaining spatial data,which decides its description complexity.It is a technology difficulty that how to realize standard coding for geographical data and break the enclosing between variable Geographical Information Systems.Using the technology of GML,SVG and Web Service,The paper realize the integration and share of distributed multisource spatial data that is a difficulty in trational WebGIS.The primary research work in this paper is following:(1) Study sufficiently the capability of GML in recognizing,managing and expressing geographical information,Based on GML3.0 cored model,design GML Application Model of point,polylin and polygon.then according as the corresponding relation of variable GIS format and GML,design and realize transformation from common GIS format,such as ShapeFile,to GML format.(2) Study the capability of SVG in visualization of geographical information,Through analyzing the relationship of GML and SVG in expressing vactor feature,Design and realize XSLT template to transform GML to SVG.(3) Analyze the superiority of Web Service in realizing compability of heterogeneous system,then study its application mechanism in WebGIS and design some Web Services for integration of multi-resource,including the service for getting GML document,metadata service for convenient for query,the service for querying and unit GML document and visualization service of geographical information.(4) Based on Web Service technology,realize a Web geograghical information system.which is a four-hiberarchy including client,Web server,integration server and distributed spatial data supporter,and servers are responsable for refering and integrating needed web services to meet the client demands,Additionally,The JavaScript in client help users to complete operations towards the map,such as zoom in,zoom out,pan and so on,The realization of WebGIS based on Web Service validated the feasibility to share distributed spatial data with GML,SVG and Web Service,and it is also supports a fresh idea to manage and allocate city spatial data in "Digital City" by an active,rational and effective way.