What are latitude and longitude?
Latitude and longitude are imaginary lines used to give any place on Earth an exact address. Latitude measures north or south of the equator; longitude measures east or west of the Prime Meridian.
Lines of latitude run east to west and are parallel to the equator, which is 0 degrees. They go up to 90 degrees north at the North Pole and 90 degrees south at the South Pole. Lines of longitude run from pole to pole and go from 0 degrees at the Prime Meridian to 180 degrees east or west.
Each degree is divided into 60 minutes, and each minute into 60 seconds, for greater precision. For example, the Eiffel Tower is at about 48.86 degrees north and 2.29 degrees east.
How sailors found longitude
Finding latitude was easy by measuring the height of the Sun or stars. Longitude was much harder, because it depends on knowing the time at a reference point. In the 1700s, English clockmaker John Harrison built accurate sea clocks called marine chronometers, finally solving the problem.
Did You Know?
One degree of latitude is always about 111 kilometers, but the distance between lines of longitude shrinks toward the poles, where they all meet.