Vehicle navigation system providing for determination of a point on the border of a map stored in memory on the basis of a destination remote from the area covered by the map

Abstract

A vehicle navigation system includes a present position detector, an input device for inputting information required for route searching, inclusive of information identifying a starting point and a destination, an output device for outputting route guidance, an information memory containing map data for route guidance within a geographical area, and border line data for a border line defining a perimeter for the geographical area. A central processing unit determines whether or not the detected present position or starting point and the destination are within the geographical area stored in the information memory, determines a crossing point on the border line responsive to a determination that the present position or the starting point and the destination are not both in the geographical area and determines a travel route from the present position or starting point to the destination, which travel route passes through the crossing point. The information memory may be an element additionally containing data identifying locations outside of the geographical area in the form of remote location data which is correlated with respective border points. This system allows the user to be guided to a proper border crossing point even when the destination is outside of the geographical area covered by the map data stored in the information memory element, e.g. a CD-ROM.