Examples

Ex15-2 In order to eliminate the uncertainty due to refraction, observations for vertical angle are made at both ends of the line as close in point of time as possible. The vertical angle at the lower of the two peaks to the upper peak is +3° 02' 05"?. The reciprocal vertical angle at the upper peak is - 3° 12' 55"?. The height of instrument are kept to be same in all observation. The slope distance between two mountain peaks determined by EDM measurement is 21,345m. Compute the difference in elevations between the two peaks.

Solution :

Average vertical angle a = (3° 02' 05" + 3° 12' 55") / 2 = 6° 15' 00 "

Difference in elevation = 21.345 sin 3° 07' 30 " + 0.0675 (21.345 cos 3° 07' 30 ")²

= (1.163 + 30.662) m

= 31.825 m

<< Back | Next >>