what is a nautical mile

A nautical mile is a unit of length used in air, marine, and space navigation, and for the definition of territorial waters. It is based on the Earths longitude and latitude coordinates, with one nautical mile equaling one minute of latitude. One minute of latitude is about 1.1 miles (1.8 kilometers) and one second of latitude covers about 105 feet (32 meters) . The international nautical mile is defined as 1,852 meters (about 6,076 ft; 1.151 mi) . The derived unit of speed is the knot, one nautical mile per hour. The nautical mile is used for measuring distance traveled through water, air, and space. It is more practical for long-distance travel, where the curvature of the Earth becomes a factor in accurate measurement. Nautical charts use latitude and longitude, so its far easier for mariners to measure distance with nautical miles. The United States and the United Kingdom used slightly different measurements for some time, but they are now all standardized.