Longitude and Latitude

Author: Zany
Published on: Apr 1, 2005

What if you were asked to find where a particular place was in the world? How would you do it? If you knew the location's coordinates or longitude or latitude, you could look it up on a map. Longitude and latitude are basically a grid system of vertical and horizontal lines.

The Equator (O degrees latitude) is defined as an imaginary circle around the Earth's surface that divides the Earth into the Northern Hemisphere and the Southern Hemisphere. It is equidistant from the poles and perpendicular to the Earth's axis of rotation.

Circles drawn around the Earth north and south of the Equator are called "parallels of latitude".

In order to define longitude, an imaginary reference point - the Prime Meridian (0 degrees longitude), located at Greenwich England - was established. (The National Marine Museum site hosts a virtual tour of the Royal Observatory, Greenwich.) Circles drawn around the Earth and going through each pole are called meridians or lines of longitude.

Lines of latitudes are parallel to each other and the Equator. Lines of longitude are not parallel to each other but are termed Great Circles, i.e. if you slice through a line of longitude, you cut through the center of the Earth. The only line of latitude that is a Great Circle is the Equator.

Latitude and longitude are angles measured in degrees, minutes and seconds, i.e. 35° 43' 9" or decimal degrees. You don't have to be a mathematician to convert between the two when there are ulitites available.

An interesting story is how a way of calculating longitude at sea in the 17th century was discovered. Latitude was easy. Just use the North Star as a reference. But an accurate timepiece was needed in order to determine longitude. John Harrison solved this problem and won the longitude prize.

Like to try your skill at calculating longitude and latitude? You are in luck. There are many web sites to help you test your navigational skills.

In order to find the treasure, you must determine the longitude and latitude of Treasure Island. Happy treasure hunting.

Also, try tracking hurricanes using longitude and latitude.

Like to measure your own latitude? You can do this with the help of an inclinometer and the North Star.

Another way to test your knowledge of latitude and longitude is to play Nova's Find Your Longitude. Don't get lost.

Anchors Aweigh is a longitude mapping game.

An interesting site is the Earth and Moon viewer. You can view the Earth at various longitude, latitude and altitude.

Have fun.