Corba-based Distributed Gis Research, Collaborative Processing

At present, the burgeoning geographical spatial information industry which is characterized with computer network technology and geographical information technology and spatial technology integration is becoming the international contest, especially the swift development of GIS is still more rapidly as the particularly swift and violent development of the every nation message expressway. With the GIS application continuously development to depth and range extension and the continuously developing of computer technology, people continuously propose the more demand at the GIS application. Owing to the world's being more open and more cooperative and GIS native distributed character, GIS is caused to develop to distributed type and cooperation orientation. The norm based on distributed GIS is continuously put forward and deepened, and newer patterns and architecture structures are continuously proposed. Among them, the distributed GIS which represents pursuing opening property and inter-operation becomes one of the most charming norms.The distributed component object models greatly promote the distributed virtual environment research which aims at cooperation. Among them, CORBA is superior to DCOM and RMI in the comprehensive comparison .It is more flexible in model implement and supports more program language and more platform and safer etc. It frequently becomes the distributed component object model which GIS programmer chooses priority. So, basing on the research of CORBA model and distributed spatial database, integrating computer supported cooperative work (CSCW), the paper adopts four tiers architectural structure to construct the distributed GIS. The client bases on TOSA(native GIS component) to display and edit spatial data and calls on CORBA application server by CORBA server agent. CORBA application server supplies correlative server such as user management server and workgroup management server and version control management server and etc so that it can respond to client requests. The database server supplies the distributed spatial data server which bases on Oracle database servers.Basing on the four tiers architectural structure, the paper adopts version management as implement to have in mind on the problem on distributed GIS cooperation. During version management, the paper adopts multi-phase synchronization control strategy. With the cooperation of version operation management module and version control management module, the paper resolves the multi-user's cooperative issue and succeeds to ensure the data consistency.The paper resolves some technology subjects on some distributed GIS aspect such as data share and cooperation, and has some theory value and practice value. It proposes some feasible schemes to build up the distributed geographic information system, and adopts the concrete implement technology to probe and attempt to develop the advanced distributed GIS in order to supply some refers to man-sized distributed GIS research and the building on computer network environment.