| 摘要 |
PROBLEM TO BE SOLVED: To suitably update the map data stored in a navigation device, in a communicating navigation device. SOLUTION: This navigation device stores the use history information of map data with map data used in displaying a map to a user. The use history information of the map data is the information showing how often the map data is used in the past. The navigation device detects whether or not there is a vacant area in a storage unit when new map data should be stored during the operation. When there is a vacant area in the storage unit, new map data can be stored in the vacant area. On the other hand, when there is no vacant area in the storage unit, according to the use history information, the map data in the storage unit is erased to produce a vacant area. Accordingly, the new map data can be stored in the thus produced vacant area. Thus, the navigation device efficiently uses the storage unit having limited storage capacity so as to store necessary map data. COPYRIGHT: (C)2004,JPO |
