(A) is map information representing reachable ranges for a moving body such as a vehicle. The map information is divided into a plurality of regions. Regions that are filled in represent reachable ranges for the moving body. In (A), there are three linked region groups representing reachable ranges for the moving body. (B) shows a state in which a label number has been assigned to each linked region group. (C) shows a state in which a linked region group having less than a certain area has been deleted from the linked region groups other than the linked region group containing the position of one's own vehicle. (D) shows a state in which a point to avoid is plotted. The point to avoid is a point to which it is not recommended that the moving body move to, for example, a node representing the terminal point of a ferry route or a node representing a traffic congestion point. (E) shows a state in which the linked region group containing the point to avoid has been deleted.