Where in the World? Latitude and Longitude

A diagram describing latitude (left) and longitude (right)

By Sara Thompson

Special to the Enterprise

Map making has been around for as long as there have been explorers. For more accurate maps and the safety of explorers, a coordinate system was first proposed by the Greek astronomer, Hipparchus around 190-120 BC. From then to now there have been countless methods to calculate position on the earth ranging from the position of the sun, studying the eclipses on other planets, measuring the difference in time between different locations, and more!

Latitude are the parallel lines that circle the earth horizontally. The equator is 0o and all lines above it are labeled as North (N), and go up to 90o at the pole. Similarly, all lines below the equator are labeled as South (S), and also go to 90o at the pole. These are measured as the surface angle to the core of the planet. For example, the equator is at 0o if you drew a line to the center of the earth, and both poles would form 900 angles.

Lines of longitude are the lines that run vertically on our globe and meet at each pole. There are 360 lines of longitude and are measured East (E) and West (W) from the Prime Meridian. Early in navigation, cartographers would make their prime meridian the capital of their country. In 1884, 25 countries came together and chose an internationally recognized Prime Meridian, that passes through the Royal Observatory in Greenwich, England. The lines of longitude increase in number both east and west of the Prime Meridian until 180o, which is half of a circle. This point on the opposite side of the world is called the International Date Line.

The latitude and longitude system we all use today took centuries to standardize. Modern GPS and other navigational tools would not work properly if not for the work of countless scientists, cartographers, sailors, and more. We can now find any city, landmark, or point on our globe by using coordinate points of latitude and longitude. To make coordinates even more specific, the addition of minutes (‘) and seconds (“) with the degrees let you know the specific distance between lines of latitude or longitude. For example, the coordinates of Davis, California are 38o 33’14” N 121o 44’17” W.

Campers in last week’s Map It! Summer Science Camp learned about and did an activity with latitude and longitude. They searched for nearby geocaches, made paper mâché globes, and made their own map of Mace Ranch Park.

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