Studies And Implementations Of Distributed Geographic Information Services

The development of GIS is highly influenced by the progress of information technology, especially the development of Internet, distributed computing and components, The motivations for adopting new technologies are derived from the essential needs of geographic information services, and the schema of traditional Geographic Information System software is being migrated from the integration of system and functions to Services and Applications, the concept of Distributed Geographic Information Services emerges as the times require. Many papers have made mention of Distributed Geographic Information Services, but there wasn't any clear comment and detail theory about it. Problems such as capacity of geo-processing, heterogeneous services' interoperation and composition are still defective in the researches of Distributed Geographic Information Services. This dissertation gives the detail on the theories and implemental methods about Distributed Geographic Information Services by the current software theories, tools and the result of author's study. A kind of service oriented Implementation architecture is put forward for the first time. The main works and creations are as the following:1. The background and current research of Distributed Geographic Information Service are analyzed, and the main problems are pointed out. Vital theory and methods based on distributed computing technology and geographic information technology are brought forward, which are the base of this thesis.2. The distributed fearures of geographic information and geographic processing are discussed. A model of geographic information and geo-processing's transferring among network's nodes is put forward as a new method for analyzing the architecture in the development of Distributed Geographic Information Services. Based on the model, the services' architecture can be divided into two parts: static service architecture and dynamic service architecture. After analyzing existent architecture, a new service oriented architecture which composed by static service and dynamic service is excogitated.3. The development of distributed computing technology is introduced, and the approaches of Geographic Information Service based these distributed computing techniques are discussed. As a result, the dissertation gives the advantages and shortcomings of them. For the first time, the applications of XML in the domain of Distributed Geographic Information Service are perfectly summarized.4. Typical static distributed geographic information services running on the Client/Server architecture are discussed and implemented with the support of component techniques and COM standards. The dissertation takes a projects as a example, introduces how to build this kind of service using ArcObjects component library in detail, gives the advantages and shortcoming of it, and advises taking this kind of service as an infrastructure which organizing and holding data in the framework of distributed geographic information service to support building dynamic services.5. The services building by traditional WebGIS techniques are static services essentially. The dissertation analyses this kind of service which running on the Browser/Server architecture with an application builded on ArcIMS, discusses its breakthroughs relative to Client/Server model and its disadvantages. Service's performance optimizing, function enhancing and rapid application developing based on the service, mobile application based on the service also are studied. Client-side labeling function is completed by JavaScript to enhance the client-side...