Abstract

A navigation system has a map memory storing map data. The road map stored in the map memory is divided into a plurality of pages further subdivided into continuous blocks. The map memory also stores identification data for the blocks and index data for various points within the map blocks. The index data includes position data for a plurality of known points. The navigation system also includes an input unit for entry of the identification data for a map memory block and/or the index data for known points, and a display unit for displaying a map block on a display monitor. A processor of the navigation system accepts entry of the index data for a travel starting point and a destination through the input unit. Based on the entered data, the processor searches for the map blocks containing the designated known points. The processor progressively expands the search area along a vector between the travel starting point and the destination. The process finds the known point closest to the travel starting point and the other known point closest to the destination along the vector and stores these as the navigation start point and the navigation end point.