Research On Application Of Ajax Technology In WebGIS

WebGIS is the direction of the development of GIS, it greatly enhanced the maintenance, release and query efficiency of spatial information. But traditional pattern of WebGIS faces many problems, such as low responding rate and poor performance of the services.At present, Ajax is the most efficient technology for client, it can make user action and server response asynchronous. Ajax can be used to shorten responding time between client and server-side, also to reduce the volume of data transmission of networks, thus the ability of WebGIS is greatly expanded.This paper mainly did the following researches:(1) In view of the defects of the stateless tactics of spatial inquiry and the shortages of caches in pure clients, the spatial data server cache is set up used to provide high-performance data access services in the network environment, and this has enhanced the flexibility of the WebGIS server as well as the systematic integrated ability, reduced the network load, and eased the bottleneck of network bandwidth.(2) Ajax engine is created in a map service system, various map data is released fast and efficiently. Through display of multithreading control, these have enhanced mutual relationship between map and user. Ajax engine have actualized the separation of logic and data which was easy to enlarge serve of map and repeat using.(3) The existing WebGIS platform is studied, its existent inadequacy is summed up, and fat client of Ajax technology structure is put forward to using. Part of original server-side business logic is transferred to client-side managed by Ajax engine, and these have actualized on-demand data access and part of load and updates in user interface, also have solved problems such as the existing network traffic of WebGIS platform, heavy pressure of server and unfriendliness of user interface.Ajax WebGIS platform is constructed through the above work. The practice approved that this platform is of clear structure and effective implementation. Meanwhile, the above mentioned technology is tightly kept up with the current direction of developing technology which will shed significant light on research and application of similar topics.