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==Nautical Mile==

==Nautical Mile==

The '''nautical mile''' is a geodetic measurement originally defined as 1 minute of arc measured along a meridian or great circle, or 1 minute of latitude. However, as we now know that the earth is not a perfect sphere the distance varies between 6067 and 6087 feet using the [[WGS84]] ellipsoid model, with an average of 6076 feet.

The '''nautical mile''' is a geodetic measurement originally defined as 1 minute of arc measured along a meridian or great circle, or 1 minute of latitude<ref>http://www.onlineconversion.com/faq_07.htm</ref>. However, as we now know that the earth is not a perfect sphere the distance varies between 6067 and 6087 feet using the [[WGS84]] ellipsoid model, with an average of 6076 feet.

In Britain the '''Admiralty nautical mile''' was defined as 6,080 feet (1,853.184 m) which is approximately one minute of latitude in the latitudes of the south of the UK. In the United States, the nautical mile was defined in the nineteenth century as 6,080.2 feet (1,853.249 m).  Some other countries had their own definitions of the nautical mile, but it is now internationally agreed to be exactly 1,852 metres or approximately 6,076.12 feet. The international standard was adopted by the US in 1954<ref>http://ts.nist.gov/WeightsAndMeasures/Publications/appxc.cfm#footnote12</ref> and by the UK in 1970.

In Britain the '''Admiralty nautical mile''' was defined as 6,080 feet (1,853.184 m) which is approximately one minute of latitude in the latitudes of the south of the UK. In the United States, the nautical mile was defined in the nineteenth century as 6,080.2 feet (1,853.249 m).  Some other countries had their own definitions of the nautical mile, but it is now internationally agreed to be exactly 1,852 metres or approximately 6,076.12 feet. The international standard was adopted by the US in 1954<ref>http://ts.nist.gov/WeightsAndMeasures/Publications/appxc.cfm#footnote12</ref> and by the UK in 1970.