| 摘要 |
PROBLEM TO BE SOLVED: To keep on displaying a map or guiding route even by the discharge of a map-information storage means by providing a second map-readout control means by which map information on a position near a present position is read out from the storage means so as to be stored in a storage means. SOLUTION: In an information readout means 2, a map storage means 1 can be separated from a system by a user's map-storage-means discharge command which is input from an input means 3. At this time, map data cannot be read out from a readout means 2. Then, the creation of display data in a display control means 8 by means of map data which is read out by a first map-readout control means 4 is changed over to the creation of display data by the control means 8 by means of map data which is read out into a second map-readout means 5 by a system control means 10. In this manner, since wide- area map data is read out into a storage means 7 before the discharge of the storage means 1 by the second map-readout control means 5, a present-position map can be displayed for many hours even after the discharge of the storage means 1. |
