1. A method for operating a map server comprising a processor, a cache memory and a network interface, the method comprising: receiving a map request from a map client over the network interface using the processor; obtaining a map signature based on the map request using the processor; accessing the cache memory using the processor; determining if the cache memory includes the map signature using the processor; if the cache memory includes the map signature, then retrieving a map associated with the map signature from the cache memory using the processor.