| 摘要 |
PURPOSE: To improve usability at the time of scroll retrieval by reducing the scale of the character data of a map image displayed on a larger scale than the scale of a small scale map image to use the character data on the small scale map image in the case of displaying a large range of map image on a display part. CONSTITUTION: When a scroll range is set by an operating part 3, a map information forming part 6 reads a small scale map image over a wide range from a CD-ROM 1 and supplies it to a buffer memory 4 so as to rewrite storage contents. The map information forming part 6 then takes out a required map image in the small scale map image stored in the buffer memory 4 and superposes character data and the like, read from a Chinese character ROM 8 and a data storage part 9, on the small scale map information of one display screen part, on a larger scale than the scale of the small scale map image while reducing the scale of characters themselves so as to form a map image with small scale characters and symbols of one display screen part. The formed map image is displayed (14) through a video RAM 10, a composing part 12 and an image converting part 13. |
