NAVIGATION SYSTEM, ROAD DECIDING METHOD, AND MAP DATA STRUCTURE

摘要

PROBLEM TO BE SOLVED: To provide a navigation system capable of accurately determining start road, without imposing the user with a load. SOLUTION: This navigation system comprises a first road acquisition means for retrieving map data, by using information indicative of an origin and for acquiring at least one of information on a road around the origin; a first distance calculation means for calculating a distance on the map information between a point closest to the origin on the road acquired by the first road acquisition means and the origin; a first road determination means for determining whether there is a place that vehicles cannot pass through, on a straight line connecting the origin and the closest point on the map data; and a start road determination means for determining the start road based on the calculation result by the first distance calculation means and the determination result by the first road determination means. COPYRIGHT: (C)2008,JPO&INPIT