Indirect Method

Indirect methods are cheaper, quicker and less laborious than direct technique. In this method, a series of guide points are chosen along a system of straight lines and their elevations are determined. These points are then plotted and contours are drawn through interpolation. The guide points commonly are not the points on the contours to be located except in case of a coincidence. For plotting of contours, the interpolation is completed with the assumption that the slope among any two adjacent guide points is uniform. A few of the indirect methods of locating ground points are given below.