Civil Engineering - Surveying - Discussion

The angle between tangent and chord is angle made by tangent in opposite segment.

To setting our simple curve using two theodolite only angular measurements are required.

Thanks @Karan and @Apcivilian.

For setting out the curve you need the Rankine's formula for calculating the deflection angles which have to be set on the two THEODOLITE so the answer should be C.

In two theodolite method, curves are staked out by angular measurements only. Accuracy attained in this method is quite high. Thus, the method is used when higher accuracy is required and when the topography is rough or field condition is difficult.

Under "Fundamental Geometry of Circular Curve";

The underlying principle of this method is that the deflection angle between a tangent (at any point on a circle) and a chord is equal to the angle which the chord subtends in the alternate segment.

It uses only angular measurement.

Can anyone give the correct explanation, please?

Answer is D.

Two theodolite method deflection angle is required, deflection angles are calculated using Rankine's formula.

Answer E is correct.

Option A, B, C are linear methods of setting out a curve. And option D is an instrumental method but in Rankine's method of deflection angles, one theodolite and one tape are used to measure angle and length respectively.

Yes, E is the correct answer because the above 4 options required linear measurements.