Research And Implementation On The Key Technologies Of The Distributed UGIS

Digital city is the prospecting trend of the city information construction. Strongly supported by information science, UGIS has developed rapidly and been broadly applied in many government administrations. Nowadays, one of the most significant research subjects related to UGIS is how to build a scalable, distributed and collaborated city service system that offers transparent unanimous synthetic service by making use of the established application in service systems.It is common that many service application systems adopt diverse GIS software. Since most GIS software corporations adopt their own information models and processing techniques to develop their products, there are great differences between service application systems. Therefore, information interoperation and system integration are the two key issues of this subject.Through analyzing several current-prevailing geography information types and GIS data formats, this paper proposes a both user-oriented and multi-resource-heterogeneous-information-system-oriented scheme that describes the urban space semantic information entity based on ontology. Moreover, ontology-based topology and semantic relationship of the urban space entity are provided. This paper also presents a synthetic query model of Ontology-Driven space information and a methodology of semantic integration.Furthermore, in order to resolve information and service sharing, the realization of distributed system integration, this paper researches several advanced distributed system techniques including Agent, P2P, Web Services and grid computing, respectively presenting system frameworkof urban space information service system based on each distributed techniques and the practical way of synthetic information service.According to the features of urban space information system, this paper establishes a collaborated and cooperated network information service system by combining the C/S multi-level construction with P2P and by using Web Services and the Agent technique.On the basis of the contents and techniques discussed above, this paper shows an urban space information service prototype driven by ontology, which proves the feasibility of system framework. The prototype system consists of client applications, synthetic information service platform applications, interfaces of different information service system and multi-level space database system. By using Web Services and Agent interfaces, the system provides multi-user-oriented distributed services based on WAN communication and integration of multi-resource information and services.