Aerial View Maps

Geography Distances Measured by aerial Photography?

A camera lens with a 6- inch focal length has an angular coverage of 86 degrees. Suppose an aerial photograph is taken vertically with no tilt at an altitude of 3500 feet over ground with an increasing slope of 5 degrees. Calculate the ground distance CB that would appear in the resulting photograph. (answer: approximately 6600 feet) (Show calculations)

Public Comments

1. 86 degrees at 3500 feet altitude would split into two triangles with the common side of 3500 feet and 43 degree angles at the top and 47 degree angles at the opposite corners. Let x be the distance CB. x is sufficiently small that the curve of the Earth can be ignored. then, x/2 would be the base of each of the triangle. 3500 / (x/2) = tangent 47 degrees 7000 / tangent 47 degrees = x x = 6528