Surveying miscellaneous
- The bearings of two inaccessible stations, S1 (Easting 500 m, Northing 500 m) and S2 (Easting 600 m, Northing 450 m) from a station S3 were observed as 225° and 153° 26' respectively. The independent Easting (in m) of station S3 is :
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Northing of S3 = 500 + L1 cos 45°
= 450 + L2 cos 26° 34'
⇒ L1 cos 45° – L2 cos26° 34' = –50
Easting of S3
= 500 + L1 sin 45° = 600 – L2 sin 26° 34'
L1 sin 45° + L2 sin 26°34' = 100
∴ L1 = 70.71, L2 = 111.80
Easting of S3 = 500 + 70.71 × sin 45° ≈ 550mCorrect Option: C
Northing of S3 = 500 + L1 cos 45°
= 450 + L2 cos 26° 34'
⇒ L1 cos 45° – L2 cos26° 34' = –50
Easting of S3
= 500 + L1 sin 45° = 600 – L2 sin 26° 34'
L1 sin 45° + L2 sin 26°34' = 100
∴ L1 = 70.71, L2 = 111.80
Easting of S3 = 500 + 70.71 × sin 45° ≈ 550m
- The combined correction due to curvature and refraction (in m) for a distance of 1 km on the surface of Earth is
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Combined correction due to curvature and refraction = 0.0673 d2
= 0.0673 × (1)2 = 0.0673Correct Option: A
Combined correction due to curvature and refraction = 0.0673 d2
= 0.0673 × (1)2 = 0.0673
- In a region with magnetic declination of 2°E, the magnetic Fore bearing(FB) of a line AB was measured as N79°50'E. There was local attraction at A. To determine the correct magnetic bearing of the line, a point O was selected at which there was no local attraction. The magnetic FB of line AO and OA were observed to be S52°40'E and N50°20'W, respectively. What is the true FB of line AB?
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δ = 2° E
Magnetic FB of AB = N 79° 50' E = 79° 50'
Corrected FB of O A = N 50° 20' = 309°40'
∴ Correct BB of OA = 129° 40'
Observed FB of AO = Observed BB of OA = 552°40' E = 127° 20'
Error = MV – TV = – 2° 20'
∴ correction = 2°20'
TB of FB of AB = N 79°50' E + δ + correction
= N 79°50' E + 2 + 2°20'
= N 84°10' ECorrect Option: C
δ = 2° E
Magnetic FB of AB = N 79° 50' E = 79° 50'
Corrected FB of O A = N 50° 20' = 309°40'
∴ Correct BB of OA = 129° 40'
Observed FB of AO = Observed BB of OA = 552°40' E = 127° 20'
Error = MV – TV = – 2° 20'
∴ correction = 2°20'
TB of FB of AB = N 79°50' E + δ + correction
= N 79°50' E + 2 + 2°20'
= N 84°10' E
- In a closed loop traverse of 1 km total length, the closing errors in departure and latitude are 0.3 m and 0.4 m, respectively. The relative precision of this traverse will be :
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e = √l² + d²
l = 0.3, d = 0.4
∴ e = √0.3² + 0.4² = √0.25 = 0.5 mRelative precision = 0.5 = 1 : 2000 1000
Correct Option: D
e = √l² + d²
l = 0.3, d = 0.4
∴ e = √0.3² + 0.4² = √0.25 = 0.5 mRelative precision = 0.5 = 1 : 2000 1000
- The chainage of the intersection point of two straights is 1585.60 m and the angle of intersection is 140°. If the radius of a circular curve is 600.00 m, the tangent distance (in m) and length of the curve (in m). respectively are
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∆ = 180° – 140° = 40°Length of curve = πR ∆ 180° = π × 600 × 40 = 418.82 m 180 Tangent distance, T = OT1 tan ∆ (OT1 = radius = R) 2 = 600 × tan 40 = 218.88 m 2
Correct Option: C
∆ = 180° – 140° = 40°Length of curve = πR ∆ 180° = π × 600 × 40 = 418.82 m 180 Tangent distance, T = OT1 tan ∆ (OT1 = radius = R) 2 = 600 × tan 40 = 218.88 m 2