| 摘要 |
PROBLEM TO BE SOLVED: To set a viewpoint altitude on three-dimensional display with superior operability and to change image display smoothly with the operation of changing a viewpoint altitude. SOLUTION: A map display device determines whether a viewpoint altitude changing switch is operated or not (S1) and in the case that it is operated, adds the ratio of change in altitude obtained by multiplying a viewpoint before the change by the ratio of change to a minimum change in altitude (a constant value of change in altitude) to obtain the amount of change in altitude (S2). In the case that the viewpoint altitude changing switch is operated to the side of a rise in altitude, the amount of change in altitude is added to the viewpoint altitude before the change to set a viewpoint altitude (S4). In the case that it is operated to the side of a drop in altitude, the amount of change in altitude is subtracted from the viewpoint altitude before the change to set a viewpoint altitude (S5). The image of a three-dimensional map is drawn on the basis of the set viewpoint altitude. |
