Question
Download Solution PDFWhich of the following expressions is correct to calculate the correction for curvature (Cc) in levelling? Where, d is the distance sighted (measured in km).
Answer (Detailed Solution Below)
Detailed Solution
Download Solution PDFExplanation:
We know Correction for the curvature is given by
Where
d = distance between points under consideration
R is the Radius of earth = 6370 km
It is always negative
Correction due to curvature
Cc =
Cc = - 0.0785 d2
Important Points
Correction due to refraction (CR) is given by 1/7th of correction due to curvature.
But it is a positive correction.
Corrections due to refraction
CR = + 0.0112 d2
Composite correction
C = - 0.0785 d2 + 0.0112 d2
C = - 0.0673 d2
where d is the distance between the staff and the instrument in km, and C is in m.
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