A Server Side Caching System for Efficient Web Map Services

In this paper, we propose a new server side caching system that supports efficient storage and retrieval of cached map image tiles. The efficiency is achieved by organizing the map image tiles of the same layer in the same file with the relationships between corresponding map image tiles on different zoom levels, combined with the use of a main memory resident data structure and hard disc indices to facilitate the process for finding the pointers to the required map image tiles. Performance evaluation shows that the new caching system can significantly reduce the hard disc access times needed to process a Web map service request.