Mile

From Free net encyclopedia

A mile is any of a number of units of distance, each in the magnitude of 1–10 km. In (contemporary) English contexts mile refers to the statute mile of 1760 yards, which is about 1609 m, or to the (international) nautical mile, being exactly 1852 m.

There have been several abbreviations for mile, with and without trailing period: mi, ml, m, M. NIST now uses and recommends “mi”, but miles per hour are usually shortened to “m.p.h.” or “MPH” instead of “mi/h”.

1 The original mile
2 Types of mile
- 2.1 Statute miles
- 2.2 Nautical miles
3 Usage of the mile
4 Other miles
5 See also
6 Reference
7 External links

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The original mile

A unit of distance called a mile was first used by the Romans and originally denoted a distance of 1000 (double) steps ("mille passuum" in Latin), which amounted, at approximately 0.75 m per (single) step, to 1500 metres per mile.

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Types of mile

In modern usage, various distances are referred to as a mile.

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Statute miles

A statute of the English parliament during the reign of Elizabeth I established the statute mile as eight furlongs or 1760 yards; that is, 5280 feet or 63360 inches. Prior to the statute, the mile in England was commonly considered 5000 feet, a length not divisible into yards, rods, or furlongs without fractions. There are two slightly different statute miles in current use:

The international mile is the distance typically meant when the word mile is used without qualification. It is defined to be precisely 1760 international yards (by definition, 0.9144 m each) and is therefore exactly 1609.344 metres (1.609344 km). It is used in the United States and the United Kingdom as part of the U.S. customary and Imperial systems of units, respectively. The international mile is equivalent to 8 furlongs, 80 chains or 5280 international feet.
The U.S. survey mile is based on an inch defined by 1 m = 39.37 inches exactly. It is equal to 5280 U.S. survey feet, 6336/3937 km or approximately 1609.347 m. One international mile is equal to 0.999 998 survey miles. The survey mile is used by the United States Public Land Survey System.

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Nautical miles

Image:RechtwKugeldreieck.png

The international nautical mile originated from the geographical mile (one and one-eighth by the original definition) and is now internationally defined to be 1852 m; but it's pervasive definition and utility is based in the original attempt (definition) to rationalize mathematically (scale) miles–circumference–of–the–earth into a useful integer multiple of length (miles) related to (Spherical trigonometry) the degrees of spherical rotation along a great circle; it works out as approximately 6,076 feet or (in demanding fast maneuvering approximations) close-enough to an even 1 arc-minute of latitude to be of great utility.
The Nautical mile is thus used in day-to-day long distance navigation estimates or important close-in restricted water piloting of vessels large or small. In the former case, it greatly simplifies the number of terms in a complex equation; in the latter case, it serves as a good-estimate basis for keeping to a deep water channel and off the rocks and shoals.
It is still universally used in that respect, although science has refined its base standard into the metric system without impacting its utility one way or another a jot.
It is universally used for aviation, naval and maritime purposes, specifically as it gives a good estimate related to degrees in an integer form without excessive error of approximation.

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Usage of the mile

See also: Metrication

The processes of metrication have seen the mile lose favour as a unit of measurement in most countries of the world. Currently the mile can only be found on roadsigns in the USA, UK, Liberia and Myanmar. However knots (nautical miles per hour) remain commonly used in international air and sea transport.

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Other miles

The Data mile is used in radar-related subjects and is equal to 6000 feet (1.8288 kilometres).
The Dutch mile, was nearly the 19th part of a degree (~5.8 kilometres).
The German mile was reckoned to be the 15th part of a degree (and thus about four nautical miles in length or 6.4 kilometres).
The Irish mile was equal to 2240 yards (2048.256 metres).
The Italian mile (~1.5 kilometres) was a thousand paces of 5 Roman feet each (the Roman foot being one fifth of an inch less than the London foot).
The Long mile, traditionally used by the Danes, Swedes, and Hungarians, was about a German mile and a half or 9.6 kilometre. Today in Norway and Sweden, a distance of 10 kilometre is most commonly referred to as a mile or metric mile, see mil.
The term Metric mile is used in sports such as athletics and speedskating, to denote a distance of 1.5 kilometres.
The Polish mile was nearly equal to the Dutch mile.
The Scottish mile was equal to 1976.5 yards (1807.3116 metres).