1. Two theodolites are placed, one at the point of curvature T1 and the other at the point of curvature T2. Get temporary adjustment in both. The vernier A of each theodolites set to zero and clamp the upper plates.
2. Bisect the point of intersection, V from theodolites at T1 and T1 from the theodolite at T2 using the lower plate main screw and then its tangent screw. Now both the theodolites are properly oriented.
3. Open the upper plate main screw of the theodolites at T1, and set the vernier A to the deflection angle D1. The line of sight is now directed along the chord T1 a. Clamp the upper plate.
4. Release the upper clamp of the theodolite at T2 and set the vernier A to the angle D1. The line of sight is now directed along the chord T2 a.
Thus the lines of sight of both the theodolites are directed towards the point 'a'.
5. Now, move a ranging rod or an arrow near the expected point 'a' until it is bisected simultaneously by the cross-hairs of both the theodolites. Locate the point 'a' on the ground at the arrow point and fix a peg at that point.
6. To locate the second point 'b', set the verniers of both the theodolites at angle Db and repeat steps (3) to (5) .
7. Locate all other points c,d,e..... in the same manner.