| 摘要 |
PURPOSE:To effect renewal of road map assuredly, by dividing an area overlapped with an administrative district in correspondence with the area included in this district and when an existing position of a vehicle plunges into the divided district, by effecting indexing of the road map to be displayed. CONSTITUTION:In an navigator image-displaying an existing vehicle position on a road map, the following measures are taken for an accurate selection and display of the road map of an area to be displayed according to the vehicle position. Namely, the road map is divided into a plurality of areas 401-404 and divide these overlapped districts 61-63 according to the area included in this overlapped district. And, when the vehicle plunges into an overlapped district, for instance, A1 district inside 62, the district allotted to this district A1 is selected as a map to be displayed next and perform an indexing of a cassette tape storing the map data. The following procedures are: as the vehicle passes, the (thumb-)indexing of the tape storing the map data corresponding to districts B1, C1 is performed and finally, the tape corresponding to C1 is selected. |
