Surveying miscellaneous


Surveying miscellaneous

  1. 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° ≈ 550m

    Correct 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


  1. 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 = 0.0673

    Correct Option: A

    Combined correction due to curvature and refraction = 0.0673 d2
    = 0.0673 × (1)2 = 0.0673



  1. 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' E

    Correct 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


  1. 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 m

    Relative 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 m

    Relative precision =
    0.5
    = 1 : 2000
    1000



  1. 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