Abstract: In a road map data generation apparatus, existing primary road map data is subjected to a deletion process according to a deletion rule to delete a portion of the data. Thus, reduced road map data is generated for a storage medium such as a memory card having a data volume smaller than the primary road map data. A navigation apparatus using the reduced road map data stored in the memory card records a restoration rule pairing with the deletion rule. Based on the restoration rule, the reduced road map data can be restored to the primary road map data. Thus, the deletion rule can decrease the data volume of the primary data to thereby generate the reduced data, whereas the restoration rule can restore the reduced data to the primary data in the navigation apparatus. This helps prevent worsening of the quality of the road map data and lowering of the user's satisfaction.

Abstract: A navigation apparatus provides a route guidance that selectively displays guidance information of a navigation route when the navigation route branches from a branch point. That is, for example, when the navigation route goes through two branch points in a series and the second branch point has plural branch roads respectively having guidance information, the navigation apparatus displays the guidance information of one of the branch roads relevant to the navigation route when a vehicle having the navigation apparatus approaches the first branch point.

Abstract: A navigation apparatus in a vehicle acquires from an outside (i) introduced party link information relative to introduced facilities, which are introduced by facilities, and (ii) introducing party link information relative to introducing facilities, which introduce facilities. If a first facility, which satisfies a search condition inputted by a user, is provided with (i) introduced party link information relative to introduced facilities which the first facility introduces, and/or (ii) introducing party link information relative to introducing facilities which introduce the first facility; the navigation apparatus displays the introduced party link information and/or introducing party link information, If the user selects an introduced facility or an introducing facility from the displayed link information, the navigation apparatus designates, as a new destination, the selected introduced facility or introducing facility.

Abstract: In a road map data generation apparatus, existing primary road map data is subjected to a deletion process according to a deletion rule to delete a portion of the data. Thus, reduced road map data is generated for a storage medium such as a memory card having a data volume smaller than the primary road map data. A navigation apparatus using the reduced road map data stored in the memory card records a restoration rule pairing with the deletion rule. Based on the restoration rule, the reduced road map data can be restored to the primary road map data. Thus, the deletion rule can decrease the data volume of the primary data to thereby generate the reduced data, whereas the restoration rule can restore the reduced data to the primary data in the navigation apparatus. This helps prevent worsening of the quality of the road map data and lowering of the user's satisfaction.

Abstract: A navigation apparatus provides a route guidance that selectively displays guidance information of a navigation route when the navigation route branches from a branch point. That is, for example, when the navigation route goes through two branch points in a series and the second branch point has plural branch roads respectively having guidance information, the navigation apparatus displays the guidance information of one of the branch roads relevant to the navigation route when a vehicle having the navigation apparatus approaches the first branch point.