z Chapter 1: The Earth and the Graticule 1 1. The Earth and the Graticule 1. Earth and the Globe: i. Directions are used by each person to determine the location of different places on earth. ii. However, for each person the direction of the same place will be different with respect to his/her location. Hence, we can infer that, directions alone are not enough to exactly determine the location of a place on earth. iii. This difficulty can be solved if lines parallel to each other are drawn around the earth. iv. The length of earth’s diameter along the north-south direction is 12714 kilometres, while that along the east-west direction is 12756 kilometres. Due to such large size of the earth and also due to the oceanic waters, uneven nature of land and forests, innumerable islands of different sizes and buildings, it is practically not possible to draw such lines around the earth. v. Hence, geographers developed a miniature model of the earth, called the Globe, to overcome this difficulty. 2. Angular Distance: i. The location of any place on the earth is determined with reference to the centre of the earth. ii. Consider a straight line joining the centre of the earth with the point on the surface of earth whose location is to be determined. This line makes an angle at the centre along with the plane of the equator. By measuring this angle, we get the location of that point on the earth. 3. Parallels of Latitude: i. The east-west circles created at some angular distance from the centre of the earth are called parallels of latitudes. ii. The angular distances of all parallels are measured in degrees and are called latitudes. iii. The angles of the parallels of latitude increases from the equator towards the north and south. 4. Equator, Northern Hemisphere, Southern Hemisphere, North Pole and the South Pole: i. The imaginary line around the earth which divides the earth into two equal hemispheres viz., the northern hemisphere and the southern hemisphere is called as the equator. ii. The degrees of the parallels are measured from the equator. Hence, the equator is considered as 0° parallel. The equator is the largest parallel and also a great circle. iii. The parallels of latitude become smaller and smaller towards the north and the south of the equator. iv. They appear as points on the extreme north and south end of the earth’s axis and are known as the North Pole and the South Pole respectively. Let’s Revise
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z
Chapter 1: The Earth and the Graticule
1
1. The Earth and the Graticule
1. Earth and the Globe:
i. Directions are used by each person to determine the location of different places on
earth.
ii. However, for each person the direction of the same place will be different with
respect to his/her location. Hence, we can infer that, directions alone are not
enough to exactly determine the location of a place on earth.
iii. This difficulty can be solved if lines parallel to each other are drawn around the
earth.
iv. The length of earth’s diameter along the north-south direction is 12714 kilometres,
while that along the east-west direction is 12756 kilometres. Due to such large size
of the earth and also due to the oceanic waters, uneven nature of land and forests,
innumerable islands of different sizes and buildings, it is practically not possible to
draw such lines around the earth.
v. Hence, geographers developed a miniature model of the earth, called the Globe, to
overcome this difficulty.
2. Angular Distance:
i. The location of any place on the earth is determined with reference to the centre
of the earth.
ii. Consider a straight line joining the centre of the earth with the point on the surface
of earth whose location is to be determined. This line makes an angle at the centre
along with the plane of the equator. By measuring this angle, we get the location of
that point on the earth.
3. Parallels of Latitude:
i. The east-west circles created at some angular distance from the centre of the earth
are called parallels of latitudes.
ii. The angular distances of all parallels are measured in degrees and are called
latitudes.
iii. The angles of the parallels of latitude increases from the equator towards the north
and south.
4. Equator, Northern Hemisphere, Southern Hemisphere, North Pole and the South
Pole:
i. The imaginary line around the earth which divides the earth into two equal
hemispheres viz., the northern hemisphere and the southern hemisphere is called
as the equator.
ii. The degrees of the parallels are measured from the equator. Hence, the equator is
considered as 0° parallel. The equator is the largest parallel and also a great circle.
iii. The parallels of latitude become smaller and smaller towards the north and the
south of the equator.
iv. They appear as points on the extreme north and south end of the earth’s axis and
are known as the North Pole and the South Pole respectively.
Let’s Revise
Std. VI: Geography Workbook
2
v. The value of each parallel of latitude is mentioned by writing the suffix ‘N’ or ‘S’ after
the measure of its angle, to denote whether they lie to the North or South of the
equator.
vi. Each parallel of latitude joins all the places which are at the same angular distance
from the equator.
vii. One can draw 181 parallels of latitude on the earth at an interval of 1°.
5. Meridians of Longitude:
i. The semicircles from North Pole to South Pole created at some angular distance from
the centre of the earth are called meridians of longitude.
ii. The angular distances of all meridians are measured in degrees.
6. Prime Meridian, Eastern hemisphere and Western Hemisphere:
i. The meridian which passes through the point associated with 0° is called as the
Prime Meridian. The angular distance of the other meridians are measured from the
prime meridian.
ii. The 0° and 180° meridians lie on the opposite sides of the globe, forming a circle.
This circle divides the earth into eastern hemisphere and western hemisphere.
iii. The length of all the meridians (i.e., the length of the semicircles) is equal.
iv. The value of each meridian is mentioned by writing the suffix ‘E’ or ‘W’ after the
measure of its angle, to denote whether they lie to the East or the West of the Prime
Meridian.
v. Each meridian of longitude joins all the places which are at same angular distance
from the Prime Meridian.
vi. One can draw 360 meridians on the earth at an interval of 1°.
7. Distance between Parallels and Meridians:
i. The exact location of every place on the earth can be found with help of the parallels
of latitude and the meridians of longitude.
ii. The distance between two adjacent parallels of latitude is same everywhere and it is
111 km.
iii. However, the distance between the adjacent meridians of longitude is not the same
everywhere. The distance between two adjacent meridians of longitude is maximum
at the equator (111 km) and goes on reducing towards the poles. It is zero at the
north and the south poles.
iv. Thus, one degree of latitude is equal to 111 km on the earth's surface, while one
degree of longitude is also equal to 111 km on the earth’s surface at the equator.
v. Each degree of latitude and longitude is further divided into minutes and seconds to
exactly locate the places lying between their two adjacent lines.
8. The Graticule:
i. The net formed by the parallels of latitude and the meridians of the longitude is
known as the Graticule.
ii. The graticule helps in determining the location of a place on the earth.
iii. Some of its modern day applications include the Geographical Information System
(GIS), Global Positioning System (GPS), Google Maps, Wikimapia and Bhuvan of ISRO
on the internet. This technology can also be accessed via mobile phones and in
motor cars.
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Chapter 1: The Earth and the Graticule
3
Tick the Correct Alternative
1. Tick the correct alternative from the options given:
i. Whose miniature model developed by the geographers is called as a globe?
Earth Moon Sun
*ii. What term is used for the imaginary east-west horizontal lines on the earth?
Meridians International Date Line Parallels
iii. What bisects the earth into northern and southern hemisphere?
Equator Prime Meridian Tropic of Cancer
*iv. Which circle appears as a point on the globe?
Equator North / South Pole Prime Meridian
*v. How many places on the earth may be located on 45° N parallel?
one many two
*vi. How many parallels are there in the northern hemisphere?
90 89 91
*vii. What is the shape of the meridian?
Circular Semicircular Points
*viii. Which circle forms the eastern and western hemisphere?
0° parallel and 0° Prime Meridian and North and
180° meridian 180° meridian South Polar circles
ix. Where does the distance between the adjacent meridians become zero?
Equator Tropic of North and
Cancer / Capricorn South Poles
*x. What do the parallels of latitude and meridians of longitude together form on the globe?
Angular Distance Hemisphere Graticule
Q
Summative Assessment
Std. VI: Geography Workbook
4
*2. Find the correct graticule out of the following and put a tick mark � against it.
Right or Wrong ? If Wrong, write the correct sentence
*1. Observe a globe and examine the following statements. Correct the wrong ones.
i. Parallels of latitude lie parallel to the Prime Meridian.