Caching Techniques for High-Performance Web Map Services

The demand for digital maps on the Internet has increased considerably in the last few years. Therefore the performance of Web Mapping Services is becoming more and more important. This article introduces different caching techniques for high performance transfer of data using standardized OGC Web Map Services (WMS). It describes and examines different caching mechanisms based on tile caching, reverse proxy caching and web application acceleration. Furthermore it demonstrates benefits, problems and how data needs to be modified for different caching techniques. The article outlines the advantages of WMS caching systems and investigates the behaviour of these systems with an increasing number of concurrent requests using benchmarking tests. This includes the examination of applicability of the INSPIRE level of service agreement (SLA) for view services.