The Researching And Developing On The WebGIS Based Web Services

WebGIS is the outcome of Internet technology and GIS technology.GIS have becomed the popular tools extending from WWW. As the network technology developed quickly,which presented by Internet,WebGIS applications have developed rapidly.Meanwhile,these also appeared many questions in WebGIS systems.Each application of GIS is alone and can not visit each other.It's hard integrate with other application.Though it can realize through CORBA or DCOM,it is tight-coupling and hard to extend and modify.It's a good way to solve these questions through Web Services and the trend of WebGIS.Pointing to the questions of existing deceloping ways of WebGIS,this thesis present a conceptual structure of WebGIS based on Web Services. This thesis concludes the following main research contents:â…  This thesis analyse the existing developing ways and the structures of WebGIS.The ways contain the technology of Server,Client and mixture. The structures contain the conventional B/S structure and the multilayer structure based on CORBA,DCOM and EJB.These existing ways and structs are hard to realize cross-platform and cross language and the data interoperative.Some of these questions are brought by Web software,such as the cross-platform and cross language problems.Others are brought by GIS software,such as the data interoperative.So,we must do research in both GIS and Web areas to efficiently solve these problems.â…¡ This thesis analyse the criterions of W3C and OGC about Web Service. At present,these are two types of standardization organizations who try to solve those problems:The organizations who pay attention to Web,such as W3C,UDDI etc,and the organizations who pay attention to geographic information share and interoperability such as ISO TC211,0GC etc.All these two organizations present the concept of Web Service,but they are different.W3C pay more attention to the technology solutions and implementations,while OGC pay more attention to the concept of services,that is,OGC emphasis the status and function of geographic information services in Web Services.In another word,OGC emphasis the framework and concepts of Web Service,W3C emphasis the implementation and technology of Web Service.In this thesis it first introduce the Web Service from W3C and OGC separately,then expatiate the effect and significance of their protocols and standards to WebGIS.â…¢ Based on the research about W3C and OGC standards, this thesis present a conceptual structure of WebGIS based on Web Services. In this structure,it utilize Web Service stack as the core technology .Then based on this conceptual structure,it present the sketch design of Data Server,Application Server and Client and the way of data interoperative based on GML.And it analyse the principle of data exchanging based GML and the way of saving the GML data.IV Based on Visual Studio .NET development platform,it present the detail design and implementation procedure of this WebGIS .At first,it present the design and implementation procedure of WMS based on ArcIMS.And then it implement the digital changchun system based on GIS Web Services Which provided by SuperMapIS.NET,this system include the design and implementation of Data Server,Application Server and Client. The development of Data Server uses the SQL Server2000. Because it use thin client application mode,so the implimentation of the client just include two aspects:the interface design and the interaction with Application Server.In the implementation of the Application Server,it mainly use the Web Service to provide the various functions to client.By these steps,it implement a 3 tier scalable WebGIS system by Web Service.This system realize the functions of zooming in,zooming out,paning,road-analysing,bus-analysing and so on. Finally, this thesis conclude the research and implementation of WebGIS system basedon Web Services,and then present the problems that need to be solved futher and the vista ofWeb Service.