What is the principle behind the two theodolite methods used to establish a simple circular curve?
1
The angle between the tangent at the point of the curve and the chord at a point is equal to the angle that the chord subtends on the opposite segment at the point of the tangent.
2
The angle of deflection at any point on a curve is the angle between the post tangent at the point of the curve and the chord from the point of the curve to that point.
3
The angle between the tangent at the point of the curve and the chord at one point is equal to twice the angle that the chord subtends on the opposite segment at the tangent point.
4
The angle of deflection for any chord is equal to the sum of the angle of deflection of the preceding chord and the angle tangent to that chord.