The Research Of GIS Collaborative Plotting Technology

As the army information construction gradually improving, the military GIS (Geographical Information System) turns to be distributed, interactive and data services-centered. In the condition of modern warfare, the plotting of the battlefield's real time trend information and collaborative plotting of staff officers in multi-services and cooperation are becoming the new demands for GIS applications. As collaborative plotting is distributed, interactive, collaborative and intercurrent, traditional concepts of GIS technology are unable to meet the new demands. Clearer understandings of the GIS collaborative plotting structure and related computer technology supports are needed.A GIS application which is constructed by spatial database technologies, users access geographic information data stored in relational databases through spatial database engine. This not only enhances the computers'capacity of managing and analyzing massive spatial data, but also makes it more suitable to establish distributed applications of multi-node cluster. Workflow technology has the virtue of rational use of existing resources, improved efficiency, process-automatic and process monitoring. The current workflow models provide effective references for workflow modeling with collaborative plotting. Computer supported cooperative work (CSCW) technology helps computer applications work in collaborative schema, and the idea of computer supported cooperative work is compatible with the real background of collaborative plotting. Therefore, integrating GIS technology, workflow technology, CSCW technology and other related technology to enhance the cooperative and interactivity of GIS plotting has important significance.In this thesis, we analyze the architecture of GIS collaborative plotting and then introduce spatial database technology, workflow technology, collaborative editing in computer supported cooperative work and other related technologies to the collaborative plotting process. According to the characteristics of collaborative plotting, we propose the concepts of the long transaction and its handling mechanism in collaborative plotting; we analyzes why concurrent operation inconsistencies occur in the processing of collaborative plotting and propose the concurrent operation conflict judgment and detection algorithm based on message mechanism; then we take appropriate measures to eliminate conflict according to the level of conflict occurs; finally, for the "later join" nodes in collaborative plotting, we take data synchronization using multi-Server points algorithm. The algorithm is based on logical time vector and can eliminate other nodes'inconsistencies generated because of parallel operation in the data synchronization process of later join nodes; the algorithm also reduces network traffic and some nodes loads.The collaborative GIS plotting technology research improves the use efficiency of GIS system. The introduction of related concepts of computer supported cooperative work technology and workflow technology enhances the accuracy and reliability of collaborative plotting business process, saves the geographic information system from previous information island effect, and increases the collaboration and communication skills of each related GIS user departments. Collaborative GIS plotting technology has wide and bright application prospects in military command, security systems and emergency departments.