| 摘要 |
PROBLEM TO BE SOLVED: To enable simultaneous display and instantaneous changeover of a plurality of moving images, by installing a plurality of storage means (memories) or the like in which a plurality of kinds of navigation data (map data or the like) are written. SOLUTION: By previously designating two kinds of reduced scales of maps by a key input circuit or the like, data of two kinds of scale maps are read from a map disk 1 at a speed twice or more the ordinary navigation processing speed. A signal processing and data controlling circuit 5 detects the reduced scale of the map data, map data of two kinds of reduced scales which are previously designated are written is storage devices 6 and 7, respectively. Image display circuit 8 processes the data, on the basis of the map data written in the storage devices 6 and 7. In the case of display command of two images, an image which simultaneously indicates two map data is displayed on the whole image plane of a display 10. In the case of display command of one image, map image of the reduced scale which is designated out of the map data in the storage devices 6 and 7 is displayed on the whole image plane of the display 10. |
