| 摘要 |
PROBLEM TO BE SOLVED: To reduce the rate of competition with other functions for access and to increase the efficiency of memory and that of route retrieval by distributing accesses to map data storage in a navigation system which uses the map data storage such as a CD-ROM. SOLUTION: In this route retrieval method, procedures (step 405-420) for setting a predetermined point in a section from a departure point to a final goal point as a temporary goal point and procedures (step 425-435) for retrieving the route from the temporary goal point to the departure point and for setting the temporary goal point or a nearby point as the departure point once a mobile has arrived at the temporary goal point or the nearby point are repeated until the rectilinear distance from the set departure point to the final goal point becomes smaller than a predetermined distance. |
