Page 121 - SST Class 06

90 O
REPRESENTATION ON FLAT SURFACE
75 O
60 O Parallels of latitudes and meridians of longitudes
can also be drawn on flat surface like maps. This
45 O
D is shown in the given figure:
30 O
A 15 O E
E
O W 75 P Q R S
C O W 60
90 O 75 O W 45 O E 0 O
60 O W O W 30 O E
45 15 O E
30 15 0 O O E O E
15 O A 40°
B
30 O a e
B 30°
45 O
c
60 O
C 20°
75 O
90 O b
D 10°
The Grid Intersecting Lines of
N
Latitudes and Longitudes d
E 0°
60° 70° 80° 90°
You have studied about the North Star known as the
In the given figure A, B, C, D, E are horizontal
Pole Star. Recall what you have learnt and answer the
lines. They represent the latitudes and P, Q, R, S
following questions:
are vertical lines representing the longitudes.
1. In which hemisphere you can observe the North
Here, horizontal lines are shown representing
Star?
latitudes in the Northern Hemisphere and verti-
2. What is the latitudinal extent of this
cal lines are shown representing East Latitudes.
hemishphere?
The Longitudes and Latitudes have also been
3. If you were to measure the angle of the Pole Star
given values as shown in the above figure. The
from your place what will it indicate?
intersection point ‘d’ has the value 0° N, 80° E
and intersection point ‘b’ reads 10° N and 60° E.
Great Circle
Can you find the values of ‘a’, ‘c’ and ‘e’. In
We have mentioned the Great Circle above. The actual practice, these intersection points when
longitude opposite to 0° is 180°. They together shown on maps represent places on earth
form Great Circle or one full circle running whether on land or in water. On the maps, the
around the earth. Similarly, opposite 1° longitude directions are also shown with the help of an
will be 179° and opposite 15° longitude will be arrow. In the above figure, the North direction
165° longitude in the other hemisphere or
(N) is always on the top of the map. Opposite it
opposite 30° E will be 150° W and so on. The
is South and to the left (when facing the map) is
two lines together will give total longitude of
West and to the right is East.
180°. Each such full circle will divide the globe
into two equal halves or hemisphere. Any circle
that divides the globe into two equal halves is Observe the given figure on the next page and
known as Great Circle. All other lines are small answer the questions below:
circles. Among latitudes only equator is the Great 1. What is the function of the prime meridian and
Circle. what is its value (in degree)? Mark this line in
the given diagram.

Social Science-6 121