Example - Surveying Readings
station | Reading | R.L. of plane of Colimation (H.I.) | Reduced level | Remarks | ||
Back sight | Inter site | Fore sight | ||||
A | 0.422 | 482.345 | B.M. 1 on the base of the pillar | |||
B | 1.285 | 0.684 | Mech. lab | |||
C | 1.793 | 0.506 | ||||
D | 4.462 | On parapet wall of a slab drain | ||||
E | 3.120 | 2.416 | ||||
F | 1.234 | 1.517 | ||||
G | 1.232 | B.M. 2 on parapet wall of old Railway bridge | ||||
Station A
H.I. – B.S. = R.L.
482.345 – 0.422 = 481.923
Station B
B.S. – F.S. + H.I.
1.285 – 0.684 + 482.345
= 482.946 (New H.I.)
New H.I. – B.S. = R.L.
482.946 – 1.285 = 481.661
Station C
B.S. – F.S. + H.I.
1.793 – 0.506 + 482.546
New H.I. – B.S. = R.L.
484.233 – 4.462 = 475.711
Station D
B.S. – F.S. + H.I.
3.120 – 2.416 + 484.233
= 484.937 (New H.I.)
New H.I. – B.S. = R.L.
484.937 – 3.120 = 481.817
Station F
B.S. – F.S. + H.I.
1.234 – 1.517 + 484.937
= 484.654 (New H.I.)
New H.I. – B.S. = R.L.
484.654 – 1.234 = 483.420
Station G
H.I. – F.S. = R.L.
484.654 – 1.232 = 483.422
Result -
station | Reading | R.L. of plane of Colimation (H.I.) | Reduced level | Remarks | ||
Back sight | Inter site | Fore sight | ||||
A | 0.422 | 482.345 | 481.923 | B.M. 1 on the base of the pillar | ||
B | 1.285 | 0.684 | 482.946 | 481.661 | Mech. lab | |
C | 1.793 | 0.506 | 484.233 | 482.440 | ||
D | 4.462 | 479.771 | On parapet wall of a slab drain | |||
E | 3.120 | 2.416 | 484.937 | 481.817 | ||
F | 1.234 | 1.517 | 484.657 | 483.420 | ||
G | 1.232 | 483.422 | B.M. 2 on parapet wall of old Railway bridge | |||
Arithmetical Check | 7.854 | 6.355 | + 1.499 | |||
7.854 – 6.355 = + 1.499 | ||||||
Arithmetical Check –
The difference between the sum of the back sight & the sum of the foresights should be equals to the difference between the first & last reduced level.
