Vehicle navigational apparatus for displaying a road map

摘要

A navigational apparatus for automotive vehicles comprises manually operated command entry keys for specifying a desired page of a road map and specifying one of first and second display scales. Road map data is stored in a memory, the data representing a plurality of nodes along travelling routes that appear on each page of the map and comprising first node data having a first level of significance and second node data having a second level of significance which are addressable in accordance with the specified scale. A data processor reads the stored data from the memory according to the specified page and the specified scale so that the first node data is read when either of the first or second scale is specified and both of the first and second node data are read when the second scale is specified. The processor converts the storage location of the read data to a coordinate location of the memory to cause a display to provide a road map.