If is the pull applied at the ends of tape in kg, is the length of tape between end marks in metres, is the weight of the tape in kg per metre run, then sag correction

Surveying and leveling is a measurement process that determines the height of the level and the distance of an area with another elevated surface.

The principle of levelling is to obtain a horizontal line of sight at which the vertical distance of a point above or below this line of sight is found.

The main purpose of balancing in the survey is: Find the heights of the given points in relation to the given data.