| The development of mobile communication, wireless network and a variety technology of mobile terminals, had gradually promoted traditional GIS to mobile GIS, which is one of the most important technologies in GIS field in the current and future. Mobile GIS has many advantages, but also faced many problems.Firstly, there are different spatial databases of geographic information system in some parts of our country. These data are independent and closed to each other, forming some "spatial information isolated islands", to some extent this will affect the terminal in a mobile network for data access, exchange and interoperability. How to discover and access to spatial information services in the open and distributed mobile network environment has become an urgent problem to be solved in the mobile GIS research field. Secondly, the current environment of mobile communications in the wireless link is much worse than broadband access. The instability in the data transmission is often caused by wireless signals multipath fading and channel congesting, which to some extent affect the data inquiring, collecting and updating. How to use the wireless network with narrow bandwidth and instability to transmit a large number of spatial data is another problem that constrains mobile GIS development.Issued for the two problems of Mobile GIS study above, the main research contents include:1.Analyze the problem between mobile GIS spatial data sharing and mutual operation in mobile networks, introduce node scheduling and route querying based on peer-to-peer network (P2P) technology to manage terminals, sessions, spatial data in the mobile network through create and publish Web services under the P2P environment.2. The author designed a GIS spatial data model on the basis of Web services distributed publishing method which is suitable for mobile devices, to maintain the consistency and integrity of spatial data, forming the access mechanism for users to access geographic information services organization, management and data distribution includes controllable multi-source, multiple levels geographic data.3. To solve the problem that mobile terminal will be affected when obtain a large number of spatial data information by the stability and bandwidth of wireless networks, propose an efficient mobile service access mechanism based on P2P node scheduling technology, which take advantages of P2P Technology’s efficiency in spatial service management and querying, thus improve the stability of the system.4. Combined with large-scale mass data (images,3D, etc.)based on P2P technology transfer and update requirements, design and develop a prototype system which using ArcGIS API for Windows Mobile in.NET environment, then evaluated performance of this system. Finally, verified the research contents of this paper. |
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