Civil Engineering - Surveying - Discussion

As in a hill or mountain on increasing the elevation horizontal intercept decreases or vice versa and we also know that the crown value of the contour (ice cream cone is upright in the case of the hill) comes in the centre.

So, now the contour interval with elevation is increasing but the width of the contour that is the horizontal intercept is decreasing so the highest value of the contour comes in the centre and the lowest value outside, Now try to understand the replica of a mountain or hill is depression or valley.

In the case of a valley the highest elevation is on ground level and elevation as well as horizontal intercept i.e width of the contour line decreases with increasing depth. So as per the rule discussed above crown level (cone of down ice cream in this case of valley) comes in the centre so the least value comes in the centre and the major value comes outside.

Thanks.

A series of closed contour line on the map indicate the depression when the higher values are outside, while the series of closed contour lines on the map indicates the hill when the higher values are inside.

Increasing value towards there center indicates hill and in a ridge line concave side of higher values inside indicates ridge line and higher values upward indicates valley.

For series of a closed contour.

1) Higher value are inside the circle is known as HILL.

And 2) higher value are outside the circle is known as DEPRESSION.

Closed contours of decreasing value towards centre indicates a depression.

Closed contours of increasing value towards centre indicates a hill.

The centre of the depression is in a lower altitude and the sides of the valley in height. So the correct answer is B.

Contour lines of decreasing order towards the centre points out that it is a hil or and area of higher elevation.

Similar to a close counter line with one or more value lower inside then it represents a valley or depression.

Closed contour lines with reducing levels towards the centre indicate pond or other depression.

If there is reduced in levels towards the centre it means there is any depression.