Patent ID: 7831383

Claim:
A map display system for performing a route guide to indicate a guide route to a destination, the system comprising: a map data storing unit storing map data including a plurality of segment data constituting a map; a display controller configured to display a map in a display unit based on the stored map data, the guided route being highlighted in the displayed map during the route guide; a map data update unit configured to obtain update data to thereby perform an update in the map data; an identifier assignment unit configured to extract a segment datum, which is changed from map data prior to the update, and assign an identifier to the extracted segment datum; a determination unit configured to determine whether a segment datum is assigned with the identifier, wherein the display controller performs a display of the segment datum, which is determined to be assigned with the identifier, in a discernible display form different from a display form for other segment data, independent of whether or not the segment datum with the identifier is included in the guide route; and an identifier deletion unit configured to delete an identifier assigned to a segment datum, which has (i) an elapsed time period posterior to the update exceeding a first predetermined time period or (ii) a cumulative display time period for the display performed by the display controller exceeding a second predetermined time period, wherein: the map data update unit is further configured to download the update data from an outside information center; and the segment datum, to which the identifier is assigned, is a road datum for displaying a road in a road map.