Project mapping for dam construction purposes is to be produced at a scale of 1/2500, with a contour interval of 2.0 m.  
A stereoplotter is to be used in which co-ordinates can be measured with a precision of 0.01 mm and parallax with a precision of 0.015 mm, and enlargement ratio, 4:1.
 
Assume (i)           Mean terrain height = h = 250 m
                               (ii)          Camera principal distance = 150 mm
                               (iii)         ‘C’ Factor = 900.
 
a.             Determine the flying height?
b.            What is the minimum scale of photography allowable?​