The planimetric map which includes the radio wave reception post of the radio wave propagation path

摘要

PROBLEM TO BE SOLVED: To find an optimum transmission spot quickly by inputting the longitudes and latitudes of a transmission spot and a reception spot, an antenna altitude, a necessary calculation range angle, and a necessary calculation interval angle to a control picture displayed on a display device, comparing them with geographic altitude data stored previously in a storage device, and calculating and displaying data. SOLUTION: A necessary calculation range angle is specified within an input range of 0.1 to 180.0 degrees and a necessary calculation interval angle is specified within an input range of 0.1 to 1.0 degree. A computer of a supervisory control unit calculates altitude values of topology on the straight line from a reception spot to the latitude and longitude of a virtual transmission spot by calculation by specified calculation interval angles. Through this calculation, the position of an obstacle cutting off the radio wave propagation path connecting the reception spot and transmission spot is found out and a meshed display 109 of the range where the obstacle present is made on the display screen 101 of the display device.