"1 sea mile"", followed by ""For most practical purposes distance is measured from the latitude scale, assuming that one minute of latitude equals one nautical mile"". One tenth of a nautical mile is a cable length. The derived unit of speed is the knot, defined as one nautical mile per hour. The metre was originally defined as of the meridian arc from the North pole to the equator passing through Dunkirk. The Earth’s circumference is therefore approximately 40,000 km. The equatorial circumference is slightly longer than the polar circumference – the measurement based on this (40,075.017 km x x ="
"Nautical mile A nautical mile (also known as an air mile) is a unit of measurement defined as exactly . Historically, it was defined as one minute of latitude, which is one sixtieth of a degree of latitude – i.e. since a minute of a degree is x = , the Earth's polar circumference is approximately 21,600 nautical miles. It is a non-SI unit which today has a continued use in both air and marine navigation, and for the definition of territorial waters. There is no single internationally agreed symbol. While using M itself, the International Bureau of Weights and"
") is known as the geographical mile. Nautical mile A nautical mile (also known as an air mile) is a unit of measurement defined as exactly . Historically, it was defined as one minute of latitude, which is one sixtieth of a degree of latitude – i.e. since a minute of a degree is x = , the Earth's polar circumference is approximately 21,600 nautical miles. It is a non-SI unit which today has a continued use in both air and marine navigation, and for the definition of territorial waters. There is no single internationally agreed symbol. While using M"
"of latitude is not constant, but about at the poles and at the Equator, with a mean value of . Other countries measure the minute of arc at 45 degrees latitude, giving the nautical mile a length of . In 1929, the international nautical mile was defined by the First International Extraordinary Hydrographic Conference in Monaco as precisely 1,852 metres. Imperial units and United States customary units used a definition of the nautical mile based on the Clarke (1866) Spheroid. The United States nautical mile was defined as based in the Mendenhall Order foot of 1893. It was abandoned in"
"accurate because they measure angles from the horizon, eliminating errors caused by the placement of an instrument's pointers, and because their dual mirror system cancels relative motions of the instrument, showing a steady view of the object and horizon. Navigators measure distance on the globe in degrees, arcminutes and arcseconds. A nautical mile is defined as 1852 meters, but is also (not accidentally) one minute of angle along a meridian on the Earth. Sextants can be read accurately to within 0.2 arcminutes, so the observer's position can be determined within (theoretically) 0.2 miles, about 400 yards (370 m). Most ocean"
"favour of the international nautical mile in 1954. The Imperial nautical mile, often called an Admiralty mile, or more correctly, an Admiralty measured mile, was defined by its relation to the Admiralty knot, 6,080 imperial feet per hour, so 1 imperial nautical mile is about 1,853.181 metres. It was abandoned in 1970 and, legally, references to the obsolete unit are now converted to 1,853 metres. Despite the existence of precise modern definitions, in the early 21st century the old definitions are still in use. The Royal Yachting Association says in its manual for day skippers: ""1 (minute) of Latitude ="
"one minute of arc along a meridian of a spherical earth. An ellipsoid model leads to a variation of the nautical mile with latitude. This was resolved by defining the nautical mile to be exactly 1,852 metres. However for all practical purposes distances are measured from the latitude scale of charts. As the Royal Yachting Association says in its manual for day skippers: ""1 (minute) of Latitude = 1 sea mile"", followed by ""For most practical purposes distance is measured from the latitude scale, assuming that one minute of latitude equals one nautical mile"". There are six auxiliary latitudes that"
"the United States, Australia, Canada, New Zealand, South Africa, and the United Kingdom defined the length of the international yard to be exactly 0.9144 metre. The British Admiralty defined a fathom to be a thousandth of an imperial nautical mile (which was 6080 ft) or . In practice the ""warship fathom"" of exactly was used in Britain and the United States. No conflict in the real world existed as depths on Imperial nautical charts were indicated in feet if less than and in fathoms for depths above that. Until the 19th century in England, the length of the fathom was"
"longitude at the equator is thus exactly 60 geographical miles. It was closely related to the nautical mile, which was originally determined as 1 minute of arc along a great circle of the Earth, but is nowadays defined as exactly 1852 metres. The US National Institute of Standards and Technology (NIST) notes that: ""The international nautical mile of 1 852 meters (6 076.115 49...feet) was adopted effective July 1, 1954, for use in the United States. The value formerly used in the United States was 6 080.20 feet = 1 nautical (geographical or sea) mile."" (6080.2 feet is 1853.24496 meters.)"
"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 . 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"
"length (inch, foot, yard and international mile) were the same in the US, though the US rarely uses some of the intermediate units, such as the (surveyor's) chain (22 yards) and the furlong (220 yards). At one time the definition of the nautical mile was based on the sphere whose surface is the same as the Clarke Ellipsoid. In the US, the full value of 1853.256 metres was used, but in the Commonwealth, this was rounded to 6080 feet (1853.184 m). These have been replaced by the international version, which rounds the sixtieth part of the 45° to the nearest"
"determine latitude at sea. He reasoned that the lines of latitude could be used as the basis for a unit of measurement for distance and proposed the nautical mile as one minute or one-sixtieth () of one degree of latitude. As one degree is of a circle, one minute of arc is of a circle – such that the polar circumference of the Earth would be exactly 21,600 miles. Gunter used Snell's circumference to define a nautical mile as 6,080 feet, the length of one minute of arc at 48 degrees latitude. In 1791, the French Academy of Sciences selected"
"1,224 ft (373 m) long by 100 ft (30.5 m) wide. The portion of the pier for berthing is approximately 525 ft (160 m) long with a deck height of 10 ft (3.1 m). Ships are required to be bow in at the Army Pier. The ""Naha Pilot Association"" provides pilots. The association has four pilots. Six hours notice must be given for scheduling a pilot and to allow time for the pilot to travel from Naha to Buckner Bay. Three Japanese commercial tugs rated at 3,200 hp are available for White Beach. A pilot is mandatory for U.S. Navy"
"latitude is 1 nautical mile. The example above would be given as 40° 11.25′ (commonly written as 11′25 or 11′.25). The older system of thirds, fourths, etc., which continues the sexagesimal unit subdivision, was used by al-Kashi and other ancient astronomers, but is rarely used today. These subdivisions were denoted by writing the Roman numeral for the number of sixtieths in superscript: 1 for a ""prime"" (minute of arc), 1 for a second, 1 for a third, 1 for a fourth, etc. Hence the modern symbols for the minute and second of arc, and the word ""second"" also refer to"
"actual position. In 1635, Henry Gellibrand published an account of yearly change in magnetic variation. In 1637, using a specially built astronomical sextant with a 5-foot radius, Richard Norwood measured the length of a nautical mile with chains. His definition of 2,040 yards is fairly close to the modern International System of Units (SI) definition of 2,025.372 yards. Norwood is also credited with the discovery of magnetic dip 59 years earlier, in 1576. In 1714 the British ""Commissioners for the discovery of longitude at sea"" came into prominence. This group, which existed until 1828, offered grants and rewards for the"
"latitude could be used as the basis for a unit of measurement for distance and proposed the nautical mile as one minute or one-sixtieth () of one degree of latitude. As one degree is of a circle, one minute of arc is of a circle (or, in radians, ). These sexagesimal (base 60) units originated in Babylonian astronomy. Gunter used Snell's circumference to define a nautical mile as 6,080 feet, the length of one minute of arc at 48 degrees latitude. Since the earth is not a perfect sphere but is an oblate spheroid with slightly flattened poles, a minute"
"Baltimax Baltimax is a naval architecture term for the largest ship measurements capable of entering and leaving the Baltic Sea in a laden condition. It is the Great Belt route that allows the largest ships. The limit is a draft of 15.4 metres and an air draft of 65 metres (limited by the clearance of the east bridge of the Great Belt Fixed Link) . The length can be around 240 m and the width around 42 m. This gives a weight of around 100.000 metric ton. Nevertheless, there are also certain larger ship types plying the baltic sea. Particularly"
"15 m draft, similar to Baltimax. The Northern Port in Gdańsk can take the 300.000 ton 15 m draft ships. Baltimax Baltimax is a naval architecture term for the largest ship measurements capable of entering and leaving the Baltic Sea in a laden condition. It is the Great Belt route that allows the largest ships. The limit is a draft of 15.4 metres and an air draft of 65 metres (limited by the clearance of the east bridge of the Great Belt Fixed Link) . The length can be around 240 m and the width around 42 m. This gives"
"(equivalent to 914.4 m), depth as ""feet"", and velocity, in some cases, as ""feet per second"". The Navy and Air Force continue to measure distance in nautical miles and speed in knots; these units are now accepted for use with SI by the BIPM. Furthermore, in military aviation NATO countries use feet for flight heights, as they do in the civilian aviation. Illegal drugs and controlled substances are often measured in metric quantities. The federal law prohibiting them defines the penalties in metric masses. In everyday use within its subculture, marijuana is sold using a combination of metric and American"
"than approximately 1/80,000. Mariners generally use the nautical mile, which, because a nautical mile is approximately equal to a minute of latitude, can be measured against the latitude scale at the sides of the chart. While linear scales are used on architectural and engineering drawings, particularly those that are drawn after the subject has been built, many such drawings do not have a linear scale and are marked ""Do Not Scale Drawing"" in recognition of the fact that paper size changes with environmental changes and only dimensions that are specifically shown on the drawing can be used reliably in precise"
"still use US customary units despite many years of informal or optional metrication. At least two states, Kentucky and California, have even moved towards demetrication of highway construction projects. Air and sea transportation commonly use the nautical mile. This is about one minute of arc of latitude along any meridian arc and it is precisely defined as 1852 metres (about 1.151 statute miles). It is not an SI unit (although it is accepted for use in the SI by the BIPM). The prime unit of speed or velocity for maritime and air navigation remains the knot (nautical mile per hour)."
"not knotted and sailors measured the length directly on the line. With the introduction of the nautical mile as a standard unit of measure at sea in the 15th century, they began to mark the line at equal intervals proportional to the nautical mile and to the time interval used for measurement. Initially, the markings were simply knots in the line. Later, sailors worked knotted cords into the log-line. Many ships used knots spaced 8 fathoms (48 feet or 14.6 meters) apart, while other ships used the 7-fathom prescription. The time interval needs to be adjusted according to the distance"
"Relative bearing In nautical navigation the relative bearing of an object is the clockwise angle from the heading of the vessel to a straight line drawn from the observation station on the vessel to the object. The relative bearing is measured with a pelorus or other optical and electronic aids to navigation such as a periscope, sonar system, and radar systems. Since World War II, relative bearings of such diverse point sources have been and are calibrated carefully to one another. The United States Navy operates a special range off Puerto Rico and another on the west coast to perform"
"United States Navy a premiere foot race to replace the disestablished Blue Angels Marathon. The length of ten nautical miles was chosen as the length because it is roughly the distance from the shore to the horizon when viewed at sea level. It was also the distance traveled by the Allied Forces on D-Day, significant because the inaugural run of the Navy Ten Nautical Miler took place on June 6, 2010, the anniversary of D-Day. A nautical mile is approximately the distance of one minute of arc of latitude on the Earth's surface. Sailors throughout history have used this form"
"metres, making the yard 0.9144018 metres and 1896 the British authorities fixed the yard as being 0.9143993 metres. At the time the discrepancy of about two parts per million was considered to be insignificant. In 1960, the United Kingdom, United States, Australia, Canada and South Africa standardised their units of length by defining the ""international yard"" as being 0.9144 metres exactly. This change affected land surveyors in the United States and led to the old units being renamed ""survey feet"", ""survey miles"" etc. However the introduction of the metric-based Ordnance Survey National Grid Surveyors in the United Kingdom in 1938"
"will always be less than 180°.). Mayer presented a detailed description of this instrument to the Board of Longitude and John Bird used the information to construct one sixteen inches in diameter for evaluation by the Royal Navy. This instrument was one of those used by Admiral John Campbell during his evaluation of the lunar distance method. It differed in that it was graduated to 360° and was so heavy that it was fitted with a support that attached to a belt. It was not considered better than the Hadley octant and was less convenient to use. As a result,"
"3,000 to 4000 yards and slant range between 4,000 and 12,000 yards Continuous contact was used. Nine courses were obtained on slow moving naval targets at ranges from 4,000 to 12,000 yards. In these latter courses continuous and broken contact were used at different times. ""It was found, throughout the tests, that the performances of the various instruments were more nearly alike when measured in external units (Reciprocal range) than when measured in terms of error at the observer's eye, in spite of marked differences in physical dimensions of the instruments. The American MI has a base length of 4.5"
"(NAD27). This had been constructed by triangulation based on the definition of the foot in the Mendenhall Order of 1893, with 1 foot = 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. 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,"
"yard. The Weights and Measures (Metric) Act of 1897 in conjunction with Order in Council 411 (1898) made this relationship official. After 1898, the de facto legal definition of the yard came to be accepted as of a meter. The yard (known as the ""international yard"" in the United States) was legally defined to be exactly 0.9144 meter in 1959 under an agreement in 1959 between Australia, Canada, New Zealand, South Africa, the United Kingdom and the United States. In the UK, the provisions of the treaty were ratified by the Weights and Measures Act of 1963. The Imperial Standard"
"Longitude Longitude (, ), is a geographic coordinate that specifies the east–west position of a point on the Earth's surface. It is an angular measurement, usually expressed in degrees and denoted by the Greek letter lambda (λ). Meridians (lines running from pole to pole) connect points with the same longitude. By convention, one of these, the Prime Meridian, which passes through the Royal Observatory, Greenwich, England, was allocated the position of 0° longitude. The longitude of other places is measured as the angle east or west from the Prime Meridian, ranging from 0° at the Prime Meridian to +180° eastward"
"original dimensions of the ship may be found. Here, the units of length are the Spanish Burgos foot (27.86 cm) and the SI metre (100 cm), respectively: length = 213 (59.53); keel = 182 (50.82); beam = 57 (16.09); draught = 28 (8.06). She was reputed to be the largest warship in the world, for which she was nicknamed ""El Escorial de los mares"" by the Spanish, until surpassed in sheer size by the new type French 120-gun ships such as ""Océan"" (1790) and ""Orient"" (1791). In 1795, her forecastle was joined to her quarterdeck to create a fourth deck"
"Using official modern definitions, one nautical mile is exactly 1.852 kilometres, which implies that 1 kilometre is about nautical miles. This modern ratio differs from the one calculated from the original definitions by less than one part in 10,000. For much of the history of mathematics, even the greatest thinkers considered it impossible to compute the length of an irregular arc. Although Archimedes had pioneered a way of finding the area beneath a curve with his ""method of exhaustion"", few believed it was even possible for curves to have definite lengths, as do straight lines. The first ground was broken"
"Yard The yard (abbreviation: yd) is an English unit of length, in both the British imperial and US customary systems of measurement, that comprises 3 feet or 36 inches. Since 1959 it is by international agreement standardized as exactly 0.9144 meters. The name derives from the Old English ', ', &c., which was used for branches, staves, and measuring rods. It is first attested in the late-7th century laws of Ine of Wessex, where the ""yard of land"" mentioned is the yardland, an old English unit of tax assessment equal to hide. Around the same time, the Lindisfarne Gospels account"