Patent ID: 8051051

Claim:
A map data processing apparatus, comprising: a recording medium drive unit that receives a recording medium in which are recorded map data including a structure having map-related information, and a structure having management information for the map-related information; an update data acquisition unit that obtains update data for the map-related information; and a computer processor that updates the map-related information recorded in the recording medium by using the update data obtained by the update data acquisition unit and the management information, and executes processing of the map data based upon the map-related information recorded in the recording medium, the update data obtained by the update data acquisition unit and the management information, wherein: a plurality of levels are defined, each in correspondence to one of a plurality of different scaling factors at which a map is rendered; a plurality of sets of the map-related information are provided in correspondence to the plurality of levels; the map is divided into a plurality of divisions at each level, and each of the plurality of sets of map-related information, corresponding to a given level, is divided into units corresponding to the plurality of divisions into which the map is divided; the divided map-related information corresponding to each of the units at all levels comprises basic data; the divided map-related information corresponding to each of the units at one or more specific levels but not all levels comprises extension data; the basic data and the extension data are provided separately from each other in case that both the basic data and the extension data are provided in the divided map-relate d information corresponding to each of the units; the basic data is used to display the map at a display device; the extension data contains information used in route search; and the computer processor executes processing of the map data by using the divided map-related information comprising the basic data and the extension data; wherein the divided map-related information corresponding to each of the units further comprises information that indicates whether the extension data is present or absent.