Gis Web Services, Rest-based Study

During recent years, the development of Information Technology has had a major impact on the development of GIS, and with the proliferation of Internet, GIS has boken the barrier of traditional pattern of closed insular systems, and begun to evolve towards Web GIS and distributed GIS. Web Services and Service Oriented Architecture are two of the cutting edge development of Information Technology, both of which have exerted deep impacts on the development of enterprise software applications. Whether GIS, which is intimately related to Information Technology, could benefit from these trends, is something that needs to be studied by GIS researchers. This paper builds upon an analysis and study of the above trends and relevant domestic and international research, and carries out a systematic analysis and study on GIS Web Services both in terms of theory and practice.The major contributions and innovations of this paper include:1. A comprehensive and indepth study of GIS Web Services in terms of research scope, current research and applications;2. A comprehensive summary of the technical backgrounds of GIS Web Services;3. Through an indepth analysis of the nature and scope of GIS interoperability, it is pointed out that interoperability based on interfaces is the major techical route to GIS interoperability;4. An analysis and contrast is made regarding major distributed computing platforms, including .Net of Microsoft, J2EE by Sun and CORBAfrom OMG, and their respective strengths and weaknesses are identified. In particular, the characteristics of SOAP based Web Services and those of REST style Web Services are compared and contrasted, and it is concluded that REST style GIS Web Services have the advantages of loose coupling, interoperability and openness, all of which is critical to GIS interoperability;5. On the basis of the concept of GIS Web Services, the technology model of REST style GIS Web Services (GWS) is proposed, which is a multi-layer architecture made up of client layer, service layer and application logic layer, and data access layer. The characteristics of different layers are explained and the advantages of GWS and its difference from Web GIS are also pointed out;6. Based on the GWS technology model, the implementation mechanisms of REST style GIS Web Services are studied, including service description, service location and discovery (representation of server metadata), service interaction/invocation and security mechanism etc;7. Continuing from the theoretical study of GIS Web Services, various aspects of designing and implementing GIS Web Services are studied, including desing goals, development methodology and technical measures;8. Agile software development methods are utilized in the development of a prototype for REST style GIS Web Services.