Editing Mile (section)

==Nautical==
[[File:RechtwKugeldreieck.svg|thumb|upright=0.5|'''On the utility of the nautical mile.'''<br />Each circle shown is a [[great circle]]—the analogue of a line in spherical trigonometry—and hence the shortest path connecting two points on the globular surface. [[Meridian (geography)|Meridians]] are great circles that pass through the poles.]]
{{Main|Nautical mile}}

The ''nautical mile'' was originally defined as one [[minute of arc]] along a [[Meridian arc|meridian]] of the Earth.{{sfnp|Maloney|1978|p=34}} Navigators use dividers to step off the distance between two points on the navigational chart, then place the open dividers against the minutes-of-latitude scale at the edge of the chart, and read off the distance in nautical miles.{{sfnp|Maloney|1978|pp=34–35}} The Earth is not perfectly spherical but an [[oblate spheroid]], so the length of a minute of latitude increases by 1% from the equator to the poles, as seen for example in the [[World Geodetic System|WGS84 ellipsoid]], with {{convert|6046|ft|m|order=flip}} at the equator, {{convert|6108|ft|m|order=flip}} at the poles and average {{convert|1852|m|ft}}.

Since 1929 the international nautical mile is defined by the First International Extraordinary Hydrographic Conference in [[Monaco]] as exactly 1,852 metres (which is {{convert|1852|m|mi|sigfig=4|disp=out|abbr=off}} or {{convert|1852|m|ft|sigfig=6|disp=out|abbr=off}}).<ref>{{SIBrochure8th|page=127}}.</ref> In the United States, the nautical mile was defined in the 19th century as {{convert|6,080.2|ft|m|2}}, whereas in the United Kingdom, the ''Admiralty nautical mile'' was defined as {{convert|6,080|ft|m|2}} and was about one minute of latitude in the latitudes of the south of the UK. Other nations had different definitions of the nautical mile.

===Related units===
The nautical mile per hour is known as the [[Knot (unit)|knot]]. Nautical miles and knots are almost universally used for aeronautical and maritime navigation, because of their relationship with degrees and minutes of latitude and the convenience of using the latitude scale on a map for distance measuring.

The [[data mile]] is used in [[radar]]-related subjects and is equal to 6,000 feet (1.8288 kilometres).{{sfnp|Rowlett|2018|loc="data mile"}} The [[radar mile]] is a unit of time (in the same way that the [[light year]] is a unit of distance), equal to the time required for a radar pulse to travel a distance of two miles (one mile each way). Thus, the radar statute mile is 10.8&nbsp;μs and the radar nautical mile is 12.4&nbsp;μs.{{sfnp|Rowlett|2018|loc="radar mile"}}