4. a) The of triangulation stations A and B, 70 km apart, have elevat…

Question

4. a) The of triangulation stations A and B, 70 km apart, have elevations 260 m and 270 m respectively. The intervening ground may be assumed to have uniform elevation of 220 m Find the minimum height of the signal at B, so that the line of sight may not pass nearer the ground than 2.4 m

b) Explain the following terms:

i) Reduction to Centre

ii) Correction for sag