Short Answer:

The characteristics of contours describe how contour lines behave on a map to represent the shape and slope of the ground. Contours always connect points of equal elevation and never cross each other. Their spacing shows how steep or gentle the slope is—closer lines mean steep slopes, while wider lines indicate flat areas.

Contours also form closed loops and bend around hills or valleys. These features help surveyors and engineers understand the terrain easily without visiting the site, making contour maps essential for planning roads, buildings, and drainage.

Detailed Explanation:

Characteristics of contours

Contours are curved or straight lines drawn on a map that connect points of the same elevation above a fixed reference point, usually sea level. These lines play a vital role in topographical maps and help in understanding the ground’s shape and slope. The behavior of contour lines follows certain rules and patterns, known as the characteristics of contours.

Key characteristics of contours:

1. Contour lines connect points of equal elevation
   This is the basic principle of contours. Every point on a contour line has the same height, meaning that if you walk along the line in real life, your elevation does not change.
2. Contour lines never cross each other
   Since one point on the ground cannot have two different elevations, two contour lines cannot intersect or overlap. If they seem to cross, it indicates an error in the map or drawing.
3. Contour spacing indicates slope

• Closely spaced lines mean a steep slope, as the height changes quickly in a short distance.
• Widely spaced lines mean a gentle slope, where elevation changes gradually.
• Even spacing suggests a uniform slope.

4. Contour lines form closed loops
   Contours always form a closed loop, either on the map or outside it. Even if the full loop is not visible on the drawing, it closes beyond the map’s edge.
5. Contours bend upstream in valleys and downstream in ridges

• When crossing a valley or stream, the contour lines bend upward (U-shape) pointing upstream.
• In the case of ridges or hills, contours form a V-shape that points downhill.

6. The difference between two contour lines is called contour interval
   This interval is constant on a single map and represents the vertical distance between adjacent contour lines. Common intervals are 0.5 m, 1 m, or 2 m, depending on the terrain.
7. Uniform slopes have evenly spaced contour lines
   Where the slope is constant, the contour lines are evenly spaced. If the slope is irregular, the spacing between lines changes.
8. Depressions or pits are shown by closed contours with hachures
   If a closed contour represents a lower area like a pit or depression, small tick marks called hachures are drawn inside the loop pointing toward lower elevation.
9. The contour lines around a hill appear as concentric circles
   The innermost circle shows the highest elevation, and each outer line shows decreasing elevation.

Conclusion

The characteristics of contours describe how contour lines behave to represent ground elevation and land features. These rules help in understanding terrain through maps and are essential for designing roads, buildings, and water drainage systems. Clear knowledge of contour features ensures better planning and safer construction.