| 摘要 |
PROBLEM TO BE SOLVED: To provide an image display device capable of keeping a predetermined ground altitude, and properly determining a flying route shielded from a destination by land forms.SOLUTION: The image display device 1 includes: a terrain database 40 for accumulating altitude data of terrains T surrounding the target O; and a maximum look-up angle extracting means 60 for extracting a location at which the loop-up angle α from the target is the maximum by using the terrain database over predetermined orientation areas with a central focus on the target; and an altitude difference operation means 60 for operating an altitude clearance which is altitude difference between a foreseeing line VL for connecting the target and the location with the maximum look-up angle and the terrain right under the line for each of difference coordinate locations surrounding the target; and a display device 70 for displaying the areas in which the altitude clearance is not more than the predetermined threshold C by overlapping on a map surrounding the target. |
