Contour Survey

The line of intersection of a level surface with the ground surface is known as the contour line or simply the contour. It can also be defined as a line passing through points of equal reduced levels. For example, a contour of 100 m indicates that all the points on this line have an RL of 100 m. Similarly, in a contour of 99 m, all points have an RL of 99 m, A map showing only the contour lines of an area is called a contour map.