FUNDAMENTALS OF SURVEYING : Measurement of horizontal angle

Measurement of horizontal angle:

Horizontal angle measurement by repetition method

 By using this method angle can be measured to a finer degree of accuracy.

 In this method angle is repeatedly measured and average angle is calculated by dividing total

angle by umber of repetitions.

Following errors are eliminated by this method.

1)      Errors due to eccentricity of verniers and centres are eliminated by taking both vernier reading.

2)      Errors due to in adjustment of line of collimation and the trunion axis are eliminated by taking both face readings.

3)      Errors due to inaccurate graduations are eliminated by taking the readings at different parts of circle.

4)      Errors due to inaccurate bisection of the object, eccentric centering, etc. may be counter balanced.

Note: errors due to ship, displacement of station signals, and want of verticality of the vertical axis etc. are not eliminated since they are all cumulative.

Direction method or reiteration method or method of series.

> Suitable for measurement of angles ofa group having a common vertex point.