1. Unnderstanding
Longitude & Latitude

2. Typical Graph
This is an example of a typical graph we are all familiar with.
The graph is made up of different “points” with lines that connect the points.

3. Each point has two values:
Typical Graph
Each point has two values:
The “X” value that runs along the horizontal “X” axis
The “Y” value that runs along the vertical “Y” axis
Y axis
X axis

4. X value is always stated first
Typical Graph
X value is always stated first
Followed by the Y value
The “origin” is the point where the 2 axes intersect with a value of (0,0) Y
(3,8)
(9,5) X
(0,0)

5. A point can also have negative (-) values
Typical Graph
A point can also have negative (-) values
Negative X values are to the left of the origin (0,0)
Negative Y values are below the origin Y
(-X,+Y)
(+X,+Y)
(0,0) X
(-X,-Y)
(+X,-Y)

6. East West, North South on The Earth
Let the X axis be the Equator.
Let the Y axis be the Prime Meridian that runs through Greenwich outside of London.
Lat/Long are the 2 grid points by which you can locate any point on earth. Y X

7. East West, North South on the Earth
Let each of the four quarters then be designated by North or South and East or West. N W E S

8. East West, North South on the Earth
The N tells us we’re north of the Equator. The S tells us we’re south of the Equator.
The E tells us that we’re east of the Prime Meridian. The W tells us that we’re west of the Prime Meridian.
(N, W)
(N, E)
(S, W)
(S, E)

9. East West, North South on the Earth
That means all points in North America will have a North latitude and a West longitude because it is North of the Equator and West of the Prime Meridian.
(N, W)
Prime Meridian

10. East West, North South on the Earth
What would be the latitude and longitude directions in Australia? ?
Prime Meridian
If you said South and East , you’re right!

11. What is Latitude?
Latitude is the distance from the equator along the Y axis.
All points along the equator have a value of 0 degrees latitude.
North pole = 90°N
South pole = 90°S
Values are expressed in terms of degrees.
90°N Y X
90°S

12. This is also true of longitude.
What is Latitude?
90°N
Each degree of latitude is divided into minutes.
Each minute is divided into 60 seconds. Y X
90°S
This is also true of longitude.

13. This is close to the latitude where you live.
What is Latitude?
For Example:
37°, 02’,51’’N
This is close to the latitude where you live.
90°N Y X
90°S

14. What is Longitude?
Longitude is the distance from the prime meridian along the X axis.
All points along the prime meridian have a value of 0 degrees longitude.
The earth is divided into two parts, or hemispheres, of east and west longitude. Y X
180°W
180°E

15. The earth is divided into 360 equal slices (meridians)
What is Longitude?
The earth is divided into 360 equal slices (meridians)
180 west and 180 east of the prime meridian Y X
180°W
180°E

16. Our latitude and longitude might be:
What is Latitude?
Our latitude and longitude might be:
37°, 03’,13’’N
76°, 29’, 45’’W
90°N Y X
90°S

17. (0,0) is off the western coast of Africa in the Atlantic Ocean.
So Where is (0,0)?
The origin point (0,0) is where the equator intersects the prime meridian.
(0,0) is off the western coast of Africa in the Atlantic Ocean.

18. See If You Can Tell In Which Quarter These Lon/Lats Are Located
1. 41°N, 21°E
2. 37°N, 76°W
3. 72°S, 141°W
4. 7°S, 23°W
5. 15°N, 29°E
6. 34°S, 151°E A B D C

19. Let's See How
You Did!
1. B
2. A
3. C
4. C
5. B
6. D

20. See if you can find those same latitude/longitude locations on a map!

21. In Summary!

22. Positioning on the Earth’s Surface
East is the direction of rotation of the Earth
Equator
Latitude 0o
Latitude: (90oN to 90oS)
North Pole
South Pole
Prime Meridian
0o Longitude
Longitude: (180oE to 180oW)
Longitude 60o West
Longitude 30o West
Longitude 60o East
90o
Longitude 30o East
66½o
Latitude 23½o North
Tropic of Cancer
23½o
21st June
22nd December
22nd Sept
20th March
90oW
60oW
30oW
90oE
30oE
60oE
23½o
900
Latitude 23½o South
Tropic of Capricorn
Longitude 90o West
Longitude 90oEast
Latitude and Longitude together enable the fixing of position on the Earth’s surface.

23. Now you’re ready to find some locations on a map!