$6)$ Explain the term Photogrammetry. $(5$ marks$)$

$6$b$)$ Explain the earth curvature correction for vertical photography. $(10$ marks$)$

$6$c$)$ Given a vertical frame aerial photograph taken from an altitude of $3000$m with a $152-$mm lens, what is the earth curvature correction for a point at image coordinate x$=59\mathrm{.}043$mm$,$ y$=72\mathrm{.}392$mm$?$ Assume the terrain elevation is $300$m and the radius of the earth is R$=6371$ km$.(10$ marks$)$