Question

An area of size $280km\times 350km$ is to be surveyed by photogrammetry. The number of photographs required to cover the area are:
Given: Format of photograph = $200mm\times 220mm$
Scale of photograph = 1 : 25000
Average terrain elevation = 380m
Longitudinal overlap = 60%
Side overlap = 40%
Focal length of camera = 210 mm

• A. 13846

Answer 1

The correct option is A 13846

Net length of single photograph = $(1-0.6)\times 220=88mm$

Net length of single photograph on earth = $88\times S=88\times 25000=2200000mm=2.2km$

Number of photographs in one line.
$N_1=\frac{350}{2.2}+1\underset{–}{\sim }161$

Net width of single photograph =

$(1-0.4)\times 220=132mm$

Net width of single photograph on earth = $132\times S=132\times 25000=3300\times {10}^{3}mm$
= 3.3km

Number of flight lines
$N_2=\frac{280}{3.3}+1\simeq 86$

Total number of photographs =
$N_1\times N_2=161\times 86=13846Nos$