Theory
It is the operation of running levels for the purpose of checking the series of levels which have been previously fix. At the end of each days work. Line of levels in run returning to the starting point of that day with the wire to checking the work done on that day.
Items required
1. Ranging rod
2. Theodolite
3. Tripod
4. Tape
5. Chain
Diagram
Procedure
The line of levels is to run dougle rodded lines. In this method to change points rear together are selected and two for sites are taken from the same set up of the instrument similarly to back sites are taken from the next setup of the instrument. In this manner to independent values of the heights of the instrument are obtained at each setup. These two values should not differ by more than 0.001 m from the previous difference.
