Two points A and B having elevations of 500 m and 300 m respectively above datum appear on the vertical photograph having focal length of 20 cm and flying altitude of 2500 m above datum. Their corrected photographic coordinates are as follows:
The length of ground line AB will be
Point | Photographic | Coordinates |
x(cm) | y(cm) | |
a | +2.65 | +1.36 |
b | -1.92 | +3.65 |
Xa=H−hafxa=2500−50020×(+2.65)=265m
Ya=H−hafya=2500−50020×(+1.36)=+136m
Xb=H−hbfxb=2500−30020×(−1.92)=−211.2m
Yb=H−hbfyb=2500−30020×(+3.65)=+401.5m
Length AB is given by
AB=√(Xa−Xb)2+(Ya−Yb)2
=√[265−(−211.2)]2+[136−401.5]2 = 545.2 m ≃ 545 m