Explain the process of chaining on sloping ground by stepping method with neat sketch.
The procedure to measure horizontal distance between the points A and B on sloping ground is as follows.
1. Two persons-leader and follower are required for chaining.
2. The follower holds the end of chain at A. The leader goes along the line with selected length of chain and ranging rod and faces the follower.
3. The selected chain length is such that it can be held truly horizontal. Once the chain is held horizontal, the point M’ of end of selected chain length is transferred to ground at M by plumb bob or dropping stone.
4. The process is repeated starting at M to get points N, O, P, Q till the end B is reached.
Total horizontal distance between A and b
L = AM, + MN’ + NO’ + OP’ + PQ’ + QB’