| 摘要 |
PROBLEM TO BE SOLVED: To provide a running-position display device whose noise is low, whose power consumption amount is small, whose life is long and by which map data can be read out at high speed. SOLUTION: In a display device, the speed of a disk readout means such as a CD-ROM drive is made variable. In the case of a route search operation, a route re-seraching operation, a scrolling operation, a three-dimensional screen display operation, a two-split display operation or the like which requires the high-speed readout of map data, its readout speed is changed to a high speed at a stage before its processing operation is started. The map data is read out at high speed when the processing operation is started actually. The speed is returned to its original speed at the point when the processing operation is finished. |
