| 摘要 |
PURPOSE: To set a correct starting point and a corrent destination point from three-dimensional roads and to guide a travelling route by providing an unselectable-node discriminating means for discriminating a node which cannot be selected by a node selection means and a virtual node, and selecting a node from a discriminated node, the node other than a virtual node and the virtual node. CONSTITUTION: It is judged whether an unexamined link data exists or not in a detailed map data including a starting point, and it is judged whether an attribute expressing the propriety of selection of read-out data is 1 or 0. In the case of 1, the distance from the starting point is computed with respect to all of virtual nodes and nodes and is set as the node of the nearest distance or a temporarily recommended node, and the distance to the starting point from the temporarily recommended node is compared in the past and at present, and if it is judged that the distance at this time is shorter, it is selected as a recommended node. It is processed with respect to all links in the map data, and when it is completed, the recommended node at that time is selected as a starting point node. The processing of selecting a destination node is similarly performed. |
