Representation of Relief Features By Contours

How do Contours represent relief features?

Before understanding how some of the relief features are represented by typical contour patterns, let us understand what basic contour patterns represent. The widely spaced contours show a gentle slope. The closely packed contour lines represent a steep slope. The closely packed contours in the higher elevation and the wider-spaced contours in the lower elevation show a concave slope.

What do the wider packed contours in the higher elevation and the closer spaced contours in the lower elevation indicate? They indicate convex slope.

The closely and widely spaced contours in an alternate manner show the terraced slope. The contours which are irregularly placed and show a mixed pattern show irregular slope.

So now let us see how these represent some common types of relief. How do you think a conical hill can be represented? It can be shown with the help of almost concentric contour lines spaced regularly.

Representation of Relief Features By Contours: What about a plateau?

A plateau is a flat-topped highland rising abruptly above the surrounding region. So, the top of the plateau is almost flat without contours or has very few contours, whereas its sides are shown by closely spaced contours. A ridge is an elongated hill and has a narrow upland area. The contours showing a ridge are more or less elliptical in shape.

You already know that a valley is a low-lying area between two hills or ridges, often occupied by a river. The contour point towards the heart of the hill. Thus the apex of the V points to the higher ground and its arm to the lower ground.

Representation of Relief Features By Contours: How will a waterfall be represented?

It is identified when several contours merge into one while crossing a river system. A sea cliff is represented on a contour map when contours run into one another and finally merge into one.

A gorge is represented by contours placed close to each other on both sides of the river So how will a U-shaped valley be represented? It is indicated by close parallel contours running on both the sides of the stream leaving a broad flat valley floor. The spacing of the contours indicates more or less a convex slope.

An escarpment is an abrupt, comparatively long, and regular steep face of a hill or ridge. It has close contour lines on one side which gradually thins out on the other side. The steep side forms the escarpment and the gentle side forms the dip. The entire region is called the escarpment.

Do you know, how to draw a Cross-section or a Profile?

So basically a relief feature shown with the help of contours on a map gives a fairly good idea about the nature of the terrain. If along a selected straight line, a portion of the relief feature is cut vertically, the side view of the cut forms the cross-section of the profile.

Do you know how these cross-sections help us? They give an exact idea about the heights, slopes, and depressions along the selected line.

Questions

1. What is represented by contour lines placed close to each other on both sides of the river?
(i) Escarpment
(ii) U shaped valley
(iii) Waterfall
(iv) Gorge

2. Which of the following will be represented by a contour in elliptical shape?
(i) Waterfall
(ii) Conical hill
(iii) U shaped hill
(iv) Ridge

3. Which of these represent several contours that merge into one while crossing a river system?
(i) Ridge
(ii) Gorge
(iii) Sea Cliff
(iv) Waterfall

4. What do the wider packed contours in the higher elevation and the closer spaced contours in the lower elevation indicate?
(i) Concave slope
(ii) Steep slope
(iii) Vertical slope
(iv) Convex slope

5. Which representation has the apex of the V points to the higher ground and its arm to the lower ground?
(i) Gorge
(ii) Escarpment
(iii) Ridge
(iv) Valley

Read More: What are Contour Lines? Characteristics of Contour Lines - Class 9