Wan Monitoring System The Webgis Subsystem Design And Research

The structure of traditional C/S monitoring system can not meet the requirements of monitoring of the wide distributing objects, the wide-area monitoring system is invented and used in the various fields of social life widely. As the information platform of wide-area monitoring system, WebGIS is used to display the information of objects directly and intuitively, combining with the geographical elements. It has been becoming the indispensable part of the wide-area monitoring system. The system of WebGIS is studied in the background of vehicle monitoring system, which has a very important practical significance.First, according to the requirements of the vehicle monitoring system, the three-layer structure of the subsystem of WebGIS is designed and each of the various modules is studied and analyzed respectively . Second, the extended relational database PostgreSQL+PostGIS is chosen to store spatial data by comparison of spatial data storage, the data is processed before imported into spatial database. The method of smooth handoff is used to solve the issue of continuity and smooth transition happened when displaying the map.The structure of the spatial database is redesigned and the PostgreSQL function is defined to solve the issue of the special query and speed up the speed of the data query. The SharpMap map engine is redesigned and rewritten with ASP.NET AJAX technology to change the response form of the presentation layer of information and resolve the issue which the presentation layer of information depends on the map object , the presentation layer of information is requested and refreshed independently ,which speed up the rsponse speed of the system, enhance the performance of the system.In the end, the design of Ajax application in the presentation layer, the response process of the presentation layer of information and the displaying forms of information in the application logic layer as well as the design of boundary data query of smooth handoff are described in detail ;At the same time , a series of optimization strategies are put forward to improve the performance of the system.