surveying indirect leveling ₪ Elevation of point N

 

We cannot measure the distance along the slope (An), not being the plumb of N. A method allowing to remove this difficulty is to choose a base AB from which the point N is visible, to measure the horizontal distance AB as well as the angles NAB and NBA.

From these measurement we can solve t-he triangle ANB and deduce the horizontal distance AN that we cannot measure.

You therfor make a second station at a point B chosen such that tghe triangle ANB is approximately equilateral.