The Global Grid

The global grid makes it possible to state the “absolute location” of a place – exactly where it is.

Absolute location – longitude & latitude – is like a global address.

Los Angeles, California: 34°N 118W°

Washington, DC: 38°N 77W°

Seattle, Washington: 47°N 122W°

Tulsa, Oklahoma: 36°N 95°W

Oklahoma City: 35°N 97W°

The absolute location of any place is the latitude + the longitude.

LATITUDE

LAT ITUDE lines are the FLAT lines.

LATITUDE lines also get shorter as you get closer to the North Pole or the South Pole.

Latitude lines run flat east and west, but they tell how far north or south you are of the Equator.

Think of latitude like the rungs of a ladder. ( Lad der sounds a lot like lat itude). It’s how you go up and down the globe.

Anywhere you are on the 30°N line, you are 30° north of the Equator.

And anywhere you are on the 30°S line, you are 30° south of the Equator.

LATITUDE

on the Equator in Ecuador

and in Brazil

Macapá, Brazil

in Gabon

in Uganda

and in Kenya

in Indonesia

Two other “famous” lines of latitude are the Tropic of Cancer and the Tropic of Capricorn.

So remember to think of lat itude like the rungs of a lad der.

Latitude is how you go up and down the globe.

up or down the globe (north or south). So latitude is all about how far you are from the Equator –

questions on latitude...

LONGITUDE

Long itude lines are always long.

Lines of longitude get closer together as they move away from the Equator & to the poles.

And longitude lines actually all meet at the poles.

Longitude lines tell us how far east or west we are from the Prime Meridian.

Anywhere you are on the 30°E line, you are 30° east of the Prime Meridian.

Anywhere you are on the 30°W line, you are 30° west of the Prime Meridian.

The Equator is a real location. But who decided where to put the Prime Meridian?

In the 1500s, when the Portuguese controlled the Atlantic, they drew the first Prime Meridian passing through the Madeira Islands. Graphicmaps.com

Portugal owned the Madeira Islands, so they thought it was a good idea to use THEIR land for the Prime Meridian location. We control the Atlantic. So, of course, it makes perfect sense that we would put the Prime Meridian through OUR land. WE are the center of the world! Graphicmaps.com

This Prime Meridian was used by most mapmakers for the next 300 years.

When the British got control of the Atlantic, they set a new Prime Meridian, right through England! Graphicmaps.com

NOW look who’s in charge of the Atlantic! England is now the center of the universe, so we will re-draw the Prime Meridian to go through England!

In 1884, 25 countries reached agreement at a conference in Washington D.C. that the location in Greenwich, England, would be the “Prime Meridian” - zero degrees. Over a period of many years, other countries accepted and adopted the decision.

the Prime Meridian Royal Observatory, Greenwich, England

in France

in Spain

in Ghana

So remember that longitude lines tell us how far east or west we are from the Prime Meridian.

questions on longitude...

0° 0° ?

This buoy marks where the Prime Meridian and the Equator intersect.