| 摘要 |
PROBLEM TO BE SOLVED: To provide a navigation system which shortens the time required for updating map data and which reduces costs for its updating by updating the map data for each region in a prescribed range. SOLUTION: The navigation system comprises a data center 51 used to download the map data in a region designated at a delivery request when the delivery request is received, and an onboard device 14 which is provided with a data storage used to store the map data and which updates the map data on a designaged region by using the map data delivered from the data center 51. The map data is provided with a hierarchical structure. In the map data delivered from the data center 51, the map data at the lowest lever corresponds to the designated region, and the map data at a high-order level corresponds to a wider region including a region corresponding to the map data at a low- order level. COPYRIGHT: (C)2004,JPO |
