Web Map Tile Services for Spatial Data Infrastructures: Management and Optimization
Ricardo Garca, Juan Pablo de Castro Fernández, Elena Verd, Mara Jess, Luisa Mara · InTech eBooks · 2012
Will-be-set-by-IN-TECH Most popular commercial services, like Google Maps, Yahoo Maps or Microsoft Virtual Earth, have already shown that significant performance improvements can be achieved by adopting this methodology, using their custom tiling schemes.The potential of tiled map services is that map image tiles can be cached at any intermediate location between the client and the server, reducing the latency associated to the image generation process.Tile caches are usually deployed server-side, serving map image tiles concurrently to multiple users.Moreover, many mapping clients, like Google Earth or Nasa World Wind, have embedded caches, which can also reduce network congestion and network delay.This chapter deals with the algorithms that allow the optimization and management of these tile caches: population strategies (seeding), tile pre-fetching and cache replacement policies.