Abstract: A method of using a DOS file system to access a file in a database is provided. In one embodiment implemented in an on-board vehicle navigation system, the file includes map data for a given geographic area. A file access table (FAT) is associated with the file system and references the file. The FAT has a plurality of locations, each location including a reference to one of the data clusters of the file and to another location in the FAT, forming a linked list of the references. The logical order in which the data clusters occur within the file is determined by following the linked list in the FAT for that file. A cluster table is then constructed for the file. The references to the data clusters are stored in consecutive locations of the cluster table according to the logical order of the data clusters within the file. The file is then accessed by sequentially accessing the consecutive locations in the cluster table to retrieve the data clusters.

Abstract: Method and apparatus for determining a route from a source location to a final destination using a vehicle navigation system having a map database. At least one intermediate destination is determined from the map database, each intermediate destination being at the other end of an intermediate route from the source location. A cost value is calculated for each intermediate destination. A best intermediate destination is selected from the at least one intermediate destination, the cost value corresponding to the best intermediate destination being lower than the cost values corresponding to any other intermediate destinations. The intermediate route corresponding to the best intermediate destination is then communicated to the user of the vehicle navigation system while a remainder route to the final destination is determined.