Systems and methods for a PDA with forced layer switching based on memory constraints

The present invention relates generally to navigational devices, and in particular to a PDA with improved processing management. Systems, devices and methods are provided for more efficient use of RAM and other resources in connection with a route calculation algorithm which quickly obtains a best or reasonable best path between two locations. A PDA includes forced layer switching capabilities. The PDA includes a processor and a memory adapted to communicate with the processor. The memory has cartographic data including any number of locations and data indicative of thoroughfares of a plurality of types connecting certain ones of the locations. The plurality of thoroughfares are organized in a hierarchy of detail levels. The processor operates on a route calculation algorithm to find a path between any two of the number of locations and the route calculation algorithm dynamically forces switching between different levels in the hierarchy of detail levels based on a set of criteria.