Longitude/ Latitude basic geography lesson for grade 10

1. Latitude and Longitude

2. Lines of longitude
• Understand that lines of longitude circle the globe and
know where the Prime Meridian is.
• Contemplate the significance of Greenwich and
establish the position of the International Date Line.
By the end of this section, you will:
Lines of longitude

3. Locating places
e Earth is like a giant ball, so how can we describe where a point is on it?
• Lines of latitude run in an east–west
direction and allow us to say how
far we are north or south.
• Lines of longitude run from north to south and
allow us to say where we are, east or west.
A system of lines is used to locate any
place on the surface of the Earth.

4. What do these numbers mean?
Where is it?
Lines of latitude and longitude are essential to navigation.
How would you describe the exact location of
Madrid?
• You could say that it is the
capital of Spain.
• You could describe it as being in
the centre of the country.
But to be most accurate you could give its latitude and
longitude.
• The position of Madrid is
40° 26' N and 3° 42' W.
Madrid

5. Lines of latitude
• Understand that lines of latitude are equally
spaced and parallel.
• Learn where the Equator, the Poles, the
Prime Meridian and the Tropics of Cancer
and Capricorn are.
By the end of this section, you will:
Lines of latitude

6. Lines of latitude are the equally spaced horizontal lines on a model globe and on the
maps in an atlas.
Latitude
There are 89 of them to the north of the Equator and
89 to the south.
Where the 90th line would be are two points, the North and
South Poles.
The Equator is the line of latitude around the
middle of the Earth.
Sometimes these lines are called parallels because they are all aligned in one direction.

7. The equator and the poles
• the Equator lies at 0°
Latitude is measured in degrees north or degrees south of the Equator:
• the North Pole is
found at 90°N
• all other latitudes have a value between 0° and
90° north or south.
• the South Pole is found
at 90°S
North
Pole
South
Pole
Equator 0°
10°
20°
30°
40°
50°
60°
70°
80°
90°
90°

8. Arctic Circle (66° 30' N)
Antarctic Circle (66° 30' S)
Tropic of Cancer (23° 30' N)
Tropic of Capricorn (23° 30' S)
Tropics and Circles
Each east-west line represents an imaginary ring around the world. As you move towards
the poles, these rings get smaller.
Certain latitudes have specific names:

9. Lines of longitude
• Understand that lines of longitude circle
the globe and know where the Prime
Meridian is.
• Contemplate the significance of Greenwich
and establish the position of the
International Date Line.
By the end of this section, you will:
Lines of longitude

10. Lines of longitude or meridians are the vertical lines on a model globe and on the maps
in an atlas.
Prime
Meridian
Longitude
These lines run around the Earth from the
North Pole to the South Pole. They divide
the world into 360°.
The Prime Meridian is the line of longitude
that runs through Greenwich. It is the line
of longitude at 0°.
0°

11. There are 180° of longitude to the
west of the Prime Meridian and
180° to the east.
Meridians
0°
30°
60°
90°
120°
150°
180°
30°
60°
90°
120°
150°
The 180° meridian is the exact
opposite of the Prime Meridian.
It can be called the
Antimeridian.
The two meridians circle the world
and divide it into east and west.

12. Why is the Prime Meridian at Greenwich?
In 1884, when the Prime Meridian was adopted as 0°, Britain was a world leader in
exploration and map making.
Therefore, navigators from other nations often used British maps which had Britain at the
centre.

13. Why is the Prime Meridian at Greenwich?
This is beneficial because time
changes by an entire day when
you cross the 180° meridian.
With the Greenwich Meridian set as 0° longitude, the 180° meridian runs through the
Pacific Ocean and crosses only a small land area in north-eastern Asia and some island
groups in the Pacific.
Pacific Ocean
If this meridian crossed a
large country, timekeeping
would be difficult.

14. To avoid confusion, the nations of the world
established a special line across which dates
change.
It swerves from the 180° meridian whenever
convenient.
This line is called the International Date Line.
International Date Line
The Date Line’s position has changed
throughout its history. In 1867 the line moved
from east of Alaska to west when the USA
bought the state from Russia.

15. Using latitude and
longitude
• Describe the location of a place on the
surface of the earth using latitude and
longitude.
• Know how to interpret geographical co-
ordinates.
By the end of this section, you will:
Using latitude and longitude

16. ‘A’ is only in latitude and not longitude.
‘A’ is first in the alphabet and latitude is written first.
‘A’ is the first letter of across and lines of latitude go across.
How to write co-ordinates
Latitude and longitude values can be used as geographical
co-ordinates to locate places accurately.
• Find the latitude of a place.
• Find the longitude of a place.
To give co-ordinates:
To remember that lines of latitude are always written first in co-ordinates and are drawn
across maps, think of ‘A’.
• Put the two values together with latitude
first.

17. How can we find the position of the location marked as A?
A
N
Latitude and longitude co-ordinates
0
20
40
6080
0
20
40
60
80
2040
60
80
20 40
• Find its latitude.
• The latitude is 20°S. A is
20° south of the equator.
• Find its longitude.
• The longitude is 20°W.
A is 20° west of the
Prime Meridian.
• Combine the values for
latitude and longitude.
• The latitude and longitude
of A is 20°S 20°W.
Always write latitude values first.