| 摘要 |
PURPOSE:To search a shortest route at high speed by controlling a search order so that the number of search nodes or search branches to be searched from each direction can be almost balanced in the process of the bidirectional search. CONSTITUTION:When a search start position and search end position are designated by a position input means, the shortest route is successively searched from the both directions of the search start position and search end position by a bidirectional searching means. The search order in the process of the bidirectional search is controlled by a search order control means so that the number of the nodes or branches to be searched can be made equal in the both directions. The search is advanced and the shortest route is determined out of the routes, for which the number of the search branches or search nodes is made coincident from the both directions. Then, the shortest route is displayed by a display means. Thus, in route data, for which the density of the node or branch is different, the number of the nodes or branches to be developed until the shortest route is discovered can be made minimum and accordingly, a shortest route search time can be shortened. |
