Taxi Dispatch System The Webgis Subsystem Design

With the rapid development of social economy and the growth in the living standard, the demand for taxi is also increasing. In order to facilitate the scheduling and management of taxi, there needs to develop a Monitoring and Scheduling System on taxi to achieve real-time monitoring and scheduling. This paper introduces a design on the information display platform which is a part of the Monitoring and Scheduling System. Using WEBGIS as such an information display platform enables the information of the controlled objects to be presented to the users more directly; it also facilitates the users to perform visualizing scheduling.The paper starts with analyzing the problems of WEBGIS. The performance of WEBGIS could be affected by the query and access of spatial data, the limitation of wire-speed and the performance efficiency of the serve. Then the subsystem of WEBGIS was divided into three layers named data logic layer, business logic layer and expression logic layer respectively. In response to these problems, the spatial database PostgreSQL+PostGIS was selected to store the spatial data, a spatial data sheet was designed and a control index was bulit to improve the query and access of the data. After that, the Opensource map engine Sharpmap was rewrite and expand the map engine by adopting the AJAX.NET, the map layer and information presenting layer were separated, which in turn reduces the transmission of the network and alleviates the burden of the server. Then a cache system was designed, by caching static pages and map in the Client it will carry less amounts of information, moreover by caching the rasterized map data in the Server, its performance efficiency is also improved. Lastly, a tile map was designed for the map layer and a marker cluster was designed aimed for the general query of vehicles during scheduling.