How Do Pilots Know Where They Are?
Imagine flying at approximately 28,000 to 35,000 feet above the surface of the earth. What would you use to locate your destination or identify your location? It is not easy to identify landmarks at that altitude. A street or map is not practical and a map of the earth doesn't work since there are no boundaries visible from the air. Weather and time of day may also make it impossible to see where they are.
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Pilots use a grid system similar to the ones we used to find places on a map. The lines on the grid intersect allowing the pilot to figure out where they are.
Some of you may have played a game called battle ship with graph paper and coordinates to locate your opponent. Pilots use a similar system to measure the distance from the equator and an imaginary line called the Prime Meridian.
Think of the earth as beach ball. We are going to divide the earth in half. Each half is known as a hemisphere. The part of the word hemi means half and the rest of the word sphere means ball or orb.
The most accurate way of measuring distance is to use a globe. The grid that we will study is known at Latitude and Longitude.
There is a trick to learning about these imaginary lines. First we are going to think of some mnemonic devices to help us remember the differences between the two sets of lines. Once we know the differences, we can understand the relationship between the two sets of lines and how they work together to help us locate places on the earth.
E-mail Carol A. Blakeslee
Last Update -- Sunday, December 11, 2005