Surveying - Engineering

Q1:

The bearings of two traverse legs AB and BC are N52° 45' E and N34° 30' E respectively. The deflection angle is

A 18° 15' E

B 18° 15' N

C 18° 15' W

D 18° 15' R

E 18° 15' L

ANS:E - 18° 15' L

B.B = F. B+180.
= 52 45'+180.
= 232 45'.

Reflection.
=fb next line - B. B.
=34 30'- 232 45'.
= - 198 15' + 180.
= - 18 15'. Deflection;

= FB of next line - BB of previous line.
= 34 30'-(52 45'+180)+360,
= 161 45',
= 180-161 45' = 18° 15'. Deflection
= FB of next line - BB of previous line.
= 34 30'-(52 45'+180)+360,
= 161 45',
= 180-161 45' = 18 15'. Back bearing of AB =180 + 52°45'=232°45'

So angle = 232°45' - 34°30'=198°15'.

Deflection angle= 180 - 198°15'= - 18°15' so -ve sign show the left. Deflection angle is measured from succeeding line to prolongation of preceding line in clock wise or anti clock wise direction. If it is in anti-clock wise direction it is "left-deflection angle", If it is in clock wise direction it is "right-deflection angle". BC should be in the SE quadrant for the Deflection angle to be 18° 15' L------------L indicates angle measured from the prolongation of the AB leg to the BC leg in an Anti-clockwise direction. New bearing = previous bearing + or - deflection.

Hear deflection is positive so consider +.

34° 30’ - 52° 45’ = deflection.

Deflection is 18° 15’ L.