In this method, points are located in the field, generally as corners of well-shaped geometrical figures such as squares, rectangles, and spot levels are determined. Elevations of desired contours are interpolated in between spot levels and contour lines are drawn by joining points of equal elevation.

Indirect methods are less expensive, less time consuming and less tedious as compared to the direct method. These methods are commonly employed in small scale surveys of large areas or during mapping of irregular surface or steep slope. There are two different ways usually employed for indirect method of contouring:

• Grid method and
• Radial line method

<< Back