– هر اینچ برابر ۲٫۵۴ سانتیمتر است 1inches= 2.54 centimeter
– هر فوت (پا) برابر ۳۰٫۴۸ سانتیمتر است 1feet = 30.5 centimeter
– هر مایل برابر ۱٫۶ کیلومتر است 1mile = 1.6 kilometer
– هر یارد برابر ۹۱٫۴۴ سانتیمتر است 1Yard = 91.44centimeter
With qualifiers, "mile" is also used to describe or translate a wide range of units derived from or roughly equivalent to the Roman mile, such as the nautical mile (now 1.852 km exactly), the Italian mile (roughly 1.852 km), and the Chinese mile (now 500 m exactly). The Romans divided their mile into 5,000 Roman feet but the greater importance of furlongs in pre-modernEngland meant that the statute mile was made equivalent to 8 furlongs or 5,280 feet in 1593. This form of the mile then spread to the British-colonized nations some of which continue to employ the mile. The US Geological Survey now employs the metre for official purposes but legacy data from its 1927 geodetic datum has meant that a separate US survey mile (6336/3937 km) continues to see some use. While most countries replaced the mile with the kilometre when switching to the International System of Units, the international mile continues to be used in some countries, such as Liberia, the United Kingdom, the United States, and a number of countries with fewer than one million inhabitants, most of which are UK or US territories, or have close historical ties with the UK or US.
The mile was usually abbreviatedm. in the past but is now sometimes written as mi to avoid confusion with the SImetre. However, derived units, such as miles per hour or miles per gallon, continue to be universally abbreviated as mph and mpg, respectively.
The present international mile is usually what is understood by the unqualified term "mile". When this distance needs to be distinguished from the nautical mile, the international mile may also be described as a "land mile" or "statute mile". In British English, the "statute mile" may refer to the present international miles or to any other form of English mile since the 1593 Act of Parliament, which set it as a distance of 1,760 yards. Under American law, however, the "statute mile" refers to the US survey mile. Foreign and historical units translated into English as miles usually employ a qualifier to describe the kind of mile being used but this may be omitted if it is obvious from the context, such as a discussion of the 2nd-century Antonine Itinerary describing its distances in terms of "miles" rather than "Roman miles".
The mile has been variously abbreviated—with and without a trailing period—as m, M, ml, and mi. The American National Institute of Standards and Technology now uses and recommends mi in order to avoid confusion with the SImetre (m) and millilitre (ml). However, derived units such as miles per hour or miles per gallon continue to be abbreviated as mph and mpg rather than mi/h and mi/gal. In the United Kingdom road signs use m as the abbreviation for mile though height and width restrictions also use m as the abbreviation for the metre, which may be displayed alongside feet and inches. The BBC style holds that "There is no acceptable abbreviation for 'miles'" and so it should be spelled out when used in describing areas.
The Roman mile (mille passus, lit. "thousand paces"; abbr. m.p.; also milia passuum[n 1] and mille) consisted of a thousand paces as measured by every other step—as in the total distance of the left foot hitting the ground 1,000 times. The ancient Romans, marching their armies through uncharted territory, would often push a carved stick in the ground after each 1,000 paces. Well-fed and harshly driven Roman legionaries in good weather thus created longer miles. The distance was indirectly standardised by Agrippa's establishment of a standard Roman foot (Agrippa's own) in 29 BCE, and the definition of a pace as 5 feet. An Imperial Roman mile thus denoted 5,000 Roman feet. Surveyors and specialized equipment such as the decempeda and dioptra then spread its use.
In modern times, Agrippa's Imperial Roman mile was empirically estimated to have been about 1,617 yards (1,479 m) in length.
The Roman mile also spread throughout Europe, with its local variations giving rise to the different units below.
Also arising from the Roman mile is the milestone. All roads radiated out from the Roman Forum throughout the Empire – 50,000 (Roman) miles of stone-paved roads. At every mile was placed a shaped stone, on which was carved a Roman numeral, indicating the number of miles from the center of Rome – the Forum. Hence, one always knew how far one was from Rome.
Arnold's c. 1500Customs of London recorded a mile shorter than previous ones, coming to 0.947 international miles or 1.524 km.
The English statute mile was established by a Weights and MeasuresAct of Parliament in 1593 during the reign of Queen Elizabeth I. The act on the Composition of Yards and Perches had shortened the length of the foot and its associated measures, causing the two methods of determining the mile to diverge. Owing to the importance of the surveyor's rod in deeds and surveying undertaken under Henry VIII, decreasing the length of the rod by 1⁄11 would have amounted to a significant tax increase. Parliament instead opted to maintain the mile of 8 furlongs (which were derived from the rod) and to increase the number of feet per mile from the old Roman value. The applicable passage of the statute reads: "A Mile shall contain eight Furlongs, every Furlong forty Poles,[n 3] and every Pole shall contain sixteen Foot and an half." The statute mile therefore contained 5,280 feet or 1,760 yards. The distance was not uniformly adopted. Robert Morden had multiple scales on his 17th-century maps which included continuing local values: his map of Hampshire, for example, bore two different "miles" with a ratio of 1 : 1.23 and his map of Dorset had three scales with a ratio of 1 : 1.23 : 1.41. In both cases, the traditional local units remained longer than the statute mile.
The Irish mile (míle or míle Gaelach) measured 2240 yards: approximately 1.27 statute miles or 2.048 kilometres. It was used in Ireland from the 16th century plantations until the 19th century, with residual use into the 20th century. The units were based on "English measure" but used a linear perch measuring 7 yards (6.4 m) as opposed to the English rod of 5.5 yards (5.0 m).
Other historical miles
Various historic miles and leagues from an 1848 German textbook, given in feet, metres, and fractions of a meridian
Scalebar on a 16th-century map made by Mercator. The scalebar is expressed in "Hours walking or common Flemish miles", and includes three actual scales: small, medium and big Flemish miles
The Dutch mile (Mijl) has had different definitions throughout history. One of the older definitions was 5600 ells. But the length of an ell was not standardised, so that the length of a mile could range between 3280 m and 4280 m. The Dutch mile also has had historical definitions of one hour's walking (Uur gaans), which meant around 5 km, or 20,000 Amsterdam or Rhineland feet (respectively 5660 m or 6280 m). Besides the common Dutch mile, there is also the geographical mile. 15 geographical Dutch miles equal one degree of longitude on the equator. Its value changed as the circumference of the earth was estimated to a better precision. But at the time of usage, it was around 7157 m. The metric system was introduced in the Netherlands in 1816, and the metric mile became a synonym for the kilometre, being exactly 1000 m. Since 1870, the term "mile" was replaced by the equivalent "kilometre". Today, the word "mile" is no longer used, apart from some old proverbs.
The German mile (Meile) was 24,000 German feet. The standardised Austrian mile used in southern Germany and the Austrian Empire was 7.586 km; the Prussian mile used in northern Germany was 7.5325 km. Following its standardisation by Ole Rømer in the late 17th century, the Danish mile (mil) was precisely equal to the Prussian mile and likewise divided into 24,000 feet. These were sometimes treated as equivalent to 7.5 km. Earlier values had varied: the Sjællandske miil, for instance, had been 11.13 km. The Germans also used a longer version of the geographical mile.
The Saxon Post mile (kursächsische Postmeile or Polizeimeile, introduced on occasion of a survey of the Saxon roads in the 1700s, corresponded to 2000 Dresden rods, equivalent to 9.062 kilometres.
The Hungarian mile (mérföld or magyar mérföld) varied from 8.3790 km to 8.9374 km before being standardised as 8.3536 km.
The Portuguese mile (milha) used in Portugal and Brazil was 2.0873 km prior to metrication.
The Russian mile (миля or русская миля, russkaya milya) was 7.468 km, divided into 7 versts.
The Croatian mile (hrvatska milja), first devised by the JesuitStjepan Glavač on a 1673 map, is the length of an arc of the equator subtended by 1/10° or 11.13 km exactly. The previous Croatian mile, now known as the "ban mile" (banska milja), had been the Austrian mile given above.
The Ottoman mile was 1,894.35 m (1.17709 mi), which was equal to 5,000 Ottoman foot. After 1933, the Ottoman mile was replaced with the modern Turkish mile (1,853.181 m).
The international mile is precisely equal to 1.609344 km (or 25146/15625 km as a fraction). It was established as part of the 1959 international yard and pound agreement reached by the United States, the United Kingdom, Canada, Australia, New Zealand, and Union of South Africa, which resolved small but measurable differences that had arisen from separate physical standards each country had maintained for the yard. As with the earlier statute mile, it continues to comprise 1,760 yards or 5,280 feet.
The old Imperial value of the yard was used in converting measurements to metric values in India in a 1976 Act of the Indian Parliament. However, the current National Topographic Database of the Survey of India is based on the metric WGS-84datum, which is also used by the Global Positioning System.
The difference from the previous standards was 2 ppm, or about 3.2 millimetres (1⁄8 inch) per mile. The U.S. standard was slightly longer and the old Imperial standards had been slightly shorter than the international mile. When the international mile was introduced in English-speaking countries, the basic geodetic datum in America was the North American Datum of 1927 (NAD27). This had been constructed by triangulation based on the definition of the foot in the Mendenhall Order of 1893, with 1 foot = 1200/3937 metres and the definition was retained for data derived from NAD27, but renamed the U.S. survey foot to distinguish it from the international foot.[n 4]
The exact length of the land mile varied slightly among English-speaking countries until the international yard and pound agreement in 1959 established the yard as exactly 0.9144 metres, giving a mile exactly 1,609.344 metres. The U.S. adopted this international mile for most purposes, but retained the pre-1959 mile for some land-survey data, terming it the U. S. survey mile. In the United States, statute mile normally refers to the survey mile, about 3.219 mm (1⁄8 inch) longer than the international mile (the international mile is exactly 0.0002% less than the U.S. survey mile).
While most countries replaced the mile with the kilometre when switching to the International System of Units, the international mile continues to be used in some countries, such as Liberia, Myanmar, the United Kingdom and the United States. It is furthermore used in a number of countries with vastly less than a million inhabitants, most of which are UK or US territories, or have close historical ties with the UK or US: American Samoa, Bahamas, Belize, British Virgin Islands, Cayman Islands, Dominica, Falkland Islands, Grenada, Guam, The N. Mariana Islands, Samoa, St. Lucia, St. Vincent & The Grenadines, St. Helena, St. Kitts & Nevis, the Turks & Caicos Islands, and the U.S. Virgin Islands.
The mile is even encountered in Canada, though this is predominantly in rail transport and horse racing, as the roadways have been metricated since 1977.
U.S. survey mile
The U.S. survey mile is 5,280 survey feet, or about 1,609.347 metres. In the United States, statute mile formally refers to the survey mile, but for most purposes, the difference between the survey mile and the international mile is insignificant—one international mile is 0.999998 U.S. survey miles—so statute mile can be used for either. But in some cases, such as in the U.S. State Plane Coordinate Systems (SPCSs), which can stretch over hundreds of miles, the accumulated difference can be significant, so it is important to note that the reference is to the U.S. survey mile.
The United States redefined its yard in 1893, but this resulted in U.S. and Imperial measures of distance having very slightly different lengths.
The North American Datum of 1983 (NAD83), which replaced the NAD27, is defined in metres. State Plane Coordinate Systems were then updated, but the National Geodetic Survey left individual states to decide which (if any) definition of the foot they would use. All State Plane Coordinate Systems are defined in metres, and 42 of the 50 states only use the metre-based State Plane Coordinate Systems. However, eight states also have State Plane Coordinate Systems defined in feet, seven of them in U.S. Survey feet and one in international feet.
State legislation in the U.S. is important for determining which conversion factor from the metric datum is to be used for land surveying and real estate transactions, even though the difference (2 ppm) is hardly significant, given the precision of normal surveying measurements over short distances (usually much less than a mile). Twenty-four states have legislated that surveying measures be based on the U.S. survey foot, eight have legislated that they be based on the international foot, and eighteen have not specified which conversion factor to use.
On the utility of the nautical mile. Each circle shown is a great circle—the analog of a line in spherical trigonometry—and hence the shortest path connecting two points on the globular surface. Meridians are great circles that pass through the poles.
The nautical mile was originally defined as one minute of arc along a meridian of the Earth. 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. 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. Using the WGS84 ellipsoid, the commonly accepted Earth model for many purposes today, one minute of latitude at the WGS84 equator is 6,046 feet and at the poles is 6,107.5 feet. The average is about 6,076 feet (about 1,852 metres or 1.15 statute miles).
In the United States, the nautical mile was defined in the 19th century as 6,080.2 feet (1,853.249 m), whereas in the United Kingdom, the Admiralty nautical mile was defined as 6,080 feet (1,853.184 m) 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, but it is now internationally defined to be exactly 1,852 metres (6,076.11548556 feet).
Related nautical units
The nautical mile per hour is known as the 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). 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 μs and the radar nautical mile is 12.4 μs.
The Scandinavian mile (mil) remains in common use in Norway and Sweden, where it has meant precisely 10 km since metrication occurred in 1889. It is used in informal situations and in measurements of fuel consumption, which are often given as litres per mil. In formal situations (such as official road signs) and where confusion may occur with international miles, it is avoided in favour of kilometres.
The Swedish mile was standardised as 36,000 Swedish feet or 10.687 km in 1649; before that it varied by province from about 6 to 14.485 km.
Before metrication, the Norwegian mile was 11.298 km.
The traditional Finnish peninkulma was translated as mil in Swedish and also set equal to 10 km during metrication in 1887, but is much less commonly used.
A comparison of the different lengths for a "mile", in different countries and at different times in history, is given in the table below. Leagues are also included in this list because, in terms of length, they fall in between the short West European miles and the long North, Central and Eastern European miles.
Over the course of time, the length of a yard changed several times and consequently so did the English, and from 1824, the imperial mile. The statute mile was introduced in 1592 during the reign of Queen Elizabeth I
Even in English-speaking countries that have moved from the Imperial to the metric system (for example, Australia, Canada, and New Zealand), the mile is still used in a variety of idioms. These include:
^Viličić, Marina; Lapaine, Miljenko (2016). "Hrvatska milja na starim kartama" [The Croatian Mile on Old Maps] (PDF). Kartografija i geoinformacije (in Croatian and English). Zagreb: Croatian Cartographic Society. 15 (25): 4–22. Retrieved 8 July 2019.
^Convert mile [statute] to mile [statute, US] "1 metre is equal to 0.000621371192237 mile [statute], or 0.000621369949495 mile [statute, US]. ... The U.S. statute mile (or survey mile) is defined by the survey foot. This is different from the international statute mile, which is defined as exactly 1609.344 metres. The U.S. statute mile is defined as 5,280 U.S. survey feet, which is around 1609.347219 metres."
^Weights and Measures Act, accessed February 2012, Act current to 2012-01-18. Canadian units (5) The Canadian units of measurement are as set out and defined in Schedule II, and the symbols and abbreviations therefor are as added pursuant to subparagraph 6(1)(b)(ii).
^Transportation Safety Board of Canada, accessed February 2012, Rail Report – 2010 – Report Number R10E0096. Other Factual Information (See Figure 1). 2. Assignment 602 travelled approximately 12 car lengths into track VC-64 and at a speed of 9 mph struck a stationary cut of 46 empty cars (with the air brakes applied) that had been placed in the track about 21⁄2 hours earlier. Canadian railways have not been metricated and therefore continue to measure trackage in miles and speed in miles per hour.
^Leopold Carl Bleibtreu: Handbuch der Münz-, Maß- und Gewichtskunde und des Wechsel-Staatspapier-, Bank- und Aktienwesens europäischer und außereuropäischer Länder und Städte. Verlag von J. Engelhorn, Stuttgart, 1863, p. 332
Klein, Herbert Arthur (1988) [Originally published 1974], The Science of Measurement: A Historical Survey, New York: Dover Publications (Previously published by Simon & Schuster as The World of Measurements: Masterpieces, Mysteries and Muddles of Metrology).
Livy (1905), Lease, Emory Bair (ed.), Ab Urbe Condita, Vol. I, XXI, & XXII, New York: University Publishing.
Owen, Aneurin, ed. (1841), "The Venedotian Code", Ancient Laws and Institutes of Wales; Comprising Laws Supposed to be Enacted by Howel the Good, Modified by Subsequent Regulations under the Native Princes prior to the Conquest by Edward the First: And Anomalous Laws, Consisting Principally of Institutions which by the Statute of Ruddlan were Admitted to Continue in Force: With an English Translation of the Welsh Text, to which are Added A few Latin Transcripts, Containing Digests of the Welsh Laws, Principally of the Dimetian Code, London: Commissioners on the Public Records of the Kingdom. (in Welsh) & (in English)
Oxford English Dictionary, 3rd ed., Oxford: Oxford University Press, 2002.