| 摘要 |
PURPOSE:To contrive the execution of a retrieval at a high speed by storing road network data consisting of roads of two areas connected by a trunk line road in a map data storage means, and retrieving a minimum impedance path extending from a departure point to an object spot based on an instruction of an input means. CONSTITUTION:Road network data 3a consisting of roads of two areas connected by a trunk line road is stored in a map data storage means 3, and a minimum impedance path extending from a departure point to an object spot based on an instruction of an input means is retrieved from the road network data 3a. In such a way, by only designating the departure point and the object spot, optimum retrieval use road network data is selected from plural pieces of road network data bases 3a which are constructed in advance, and since an operation is executed by using its network data as it is, the retrieval can be executed at a high speed. |
