Unnderstanding Longitude & Latitude

Bell-ringer 8/9/2016 What is absolute location? What is relative location? How do we use both of these when describing a place?

Relative Location A location of a place in relation to another place (i.e. south or downhill). Often uses cardinal directions (East, West, South North) Does not give an exact location.

Absolute Location A point on the earth's surface expressed by a coordinate system such as latitude and longitude. Often used to express an exact location on the earth.

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.

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 Typical Graph Y axis X axis

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) Typical Graph Y (3,8) (9,5) X (0,0)

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 Typical Graph Y (-X,+Y) (+X,+Y) (0,0) X (-X,-Y) (+X,-Y)

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

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

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)

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

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!

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. What is Latitude? 90°N Y X 90°S

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

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

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

(0,0) is off the western coast of Africa in the Atlantic Ocean. 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. So Where is (0,0)?

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

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

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

In Summary!

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.

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