X = 8; H = 4000; f = 152.4 mm
Aerial photography is to be taken of a tract of land that is X mi square. Flying height will be H ft above average terrain, and the camera has focal length f. If the focal plane opening is 9 X 9 in. and minimum sidelap is 30 percent, how many flight lines will be needed to cover the tract for the data given in the above problem.