What is CONTOURING? What does CONTOURING mean? CONTOURING meaning, definition & explanation

Contouring

* A contour line is a imaginary line which connects points of equal elevations.

* The vertical distance between two consecutive contour lines is called contour interval.

* Some important characteristics of contours are:

1. Widely spaced contour – flat surface

2. Closely spaced contour – steep ground

3. Equally spaced – uniform slope

4. Approximately concentric closed contours with decreasing values towards centre – pond.

5. Concentric closed contour with increasing values towards centre – hill

6. V-shaped contours with convexity towards higher ground – valley

7. U-shaped contour with convexity towards lower ground – ridge

8. If contour lines meet – existence of cliff or well

9. If contour lines cross – overhanging cliff or cave

* Methods of contouring:

1. Direct method: In this method vertical and horizontal contours of the points selected on the

selected contour lines are established.

2. Indirect method: The points are selected first and their reduced levels are found. Then

contour lines are drawn by any one of the following methods.

(a) Estimation

(b) Arithmetic calculations

* Contour maps are useful for the following civil engineering works:

1. Preliminary selection of project works

2. Drawing the sections

3. Determination of intervisibility

4. Location of routes

5. Determining catchment area

6. Calculation of reservoir capacity.