"Now for longitude! Get out the paint bucket! Just imagine someone painted 360 equally spaced lines on the surface of the sphere, each line extending from pole to pole. I've only shown a few of the lines on my drawing. Each of the 360 lines is called a MERIDIAN or LINE OF LONGITUDE!"
"360 - like the number of degrees in a circle?!"
"Right on, Lou! Then, the lines are numbered. The line that passes through Greenwich (a suburb of London, England) is called the PRIME MERIDIAN. Its longitude is 'zero' degrees. Then, going towards the east, the lines are numbered from 1 to 180 degrees; going to the west, the lines are also numbered from 1 to 180 degrees, but going the other way. All the 'east' lines between 0° and 180° (blue numbers) have the letter 'E' attached to them; all the 'west' lines between 0° and 180° (pink numbers) have a 'W' attached to them. The '0' and '180' degree lines (red numbers) do not have a letter attached to them!"

"Why such a long face, Lou! Go back to the 'Latitude and Longitude Menu' and click on 'Latitude and Longitude - Putting it all Together'"

© 2010 David Leveson/Revised by G. Rocha and Michelle O'Dea