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GATE 2018 CE (CE1) – Question 46

Geomatics Engineering · Photogrammetry: scale, flying height, parallax, camera calibration · 2 marks · Multiple choice

A horizontal 100 m × 100 m square at elevation 650 m appears as 1 cm² on a vertical aerial photograph. Camera focal length is 150 mm. Camera elevation is ______.

  1. 800 m
  2. 1500 m
  3. 2150 m
  4. 3150 m

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Show answer and explanation

Correct answer: (C) 2150 m

Explanation

A 100 m ground side images as 1 cm, so scale is 1:10000. Height above terrain is $0.15(10000)=1500$ m. Add the terrain elevation: camera elevation is $1500+650=2150$ m (C).