Chapter Name: Contours
Give the terms used in contours for each of the following
A number preceded by a dot.
The numerical difference between two contour lines.
A number preceded by a triangle.
The difference between maximum and minimum height in areas of steep slope.
The accurate height of some point marked above the ground.
Contour interval means the difference of height between two consecutive contours. For example, if one thick contour shows the height 300 metres and the next thin contour depicts the height of 320 metres. Then, the contour interval is 20 metres.
The vertical distance between any two contour lines is called vertical interval.
The actual distance between two points on two contour lines is called horizontal equivalent.
The ratio between the vertical height and the horizontal distance of a slope of land measured along the ground is called gradient.
Gentle Slope and Steep Slope
|Gentle Slope||Steep Slope|
|In gentle slopes, the change of elevation is gradual. Normally about 1:25 gradient of elevation is gradual.||Steep slope suddenly slopes up or down.|
|The contours are placed wide apart in gentle slope.||For steep slopes, the contours are drawn close to one another.|
Scarp and Dip
|A scarp has a narrow top with a steep slope.||A dip has a narrow top with a gentle slope.|
|The contour lines are closer to each other.||The contour lines are spread far apart.|
|It has a gradient of 1:3.||It has a gradient of about 1:12.|
Ridge and Water Divide
|It is a long and narrow highland sloping steeply downwards on its sides.||A line which separates two adjacent drainage basins is known as water divide.|
|Contours showing a ridge are elongated and are closely spaced.||The side on which the ridge is steeper, the contours are drawn closely together, whereas the side on which the ridge is gentle, the contours are drawn far apart.|
What is a ‘contour’?
Contour lines are imaginary lines which are drawn on a map to join places having the same height above the mean sea level.
Give two points of difference between Bench Mark and Spot Height.
|Bench Mark||Spot Height|
|These are marks etched on stone or a building to indicate the accurate height determined by surveys.||It refers to the height of a point on the ground above the mean sea level.|
|It is written as “BM” followed by a number.||It is represented by a dot followed by a number on the map.|
What do you understand by V.I. and H.E.?
V.I. stands for the vertical interval. It is the vertical distance between any two contour lines.
H.E. stands for a horizontal equivalent. It is the actual distance between two points on two contour lines.
What advantages do contours have over hill-shading and hachuring?
Hill shading and hachuring only give an impression of the slope but do not indicate the heights of the land above sea level, whereas the contours show both impression of the slope as well as the heights of the land above the sea level.
Why do two contours never intersect each other?
Two contours never intersect each other because each line represents a separate elevation, and we can’t have two different elevations at the same point.
What is meant by relief?
Relief refers to actual configuration of land which includes its altitude and slope. The relief features found on the earth’s surface include mountains, valleys, hills, plains and plateaus.
State the three methods used to show the earth’s relief features.
The three methods used to show the earth’s relief features are-
- hill shading
What do the contour lines represent?
Contour lines are imaginary lines joining places which have the same height above mean sea level.
How do contour lines show different slopes of land?
The contour lines are shown by brown colour as thick brown lines and thin brown lines. Contour lines show:
1. Elevation of land: The height of a contour is indicated by figures inserted in a break in the line.
2. Steepness of its slope: When the contours are very close, they represent steep slopes. When they are farther apart, they represent gradually increasing slopes. The absence of contour lines indicates that the land is flat i.e., a low land.
3. Shape of land at various heights: The contour lines indicate the shape of the land. For example, almost circular contours whose value decreases inside represent a lake.
This post is all about the solution of class 10 icse subject geography for chapter 2 Contours