"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"
"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)."
"as myrio-) is obsolete and not included among the prefixes when the International System of Units was introduced in 1960. 10 kilometres is equal to: A length of 100 kilometres (about 62 miles), as a rough amount, is relatively common in measurements on Earth and for some astronomical objects. It is the altitude at which the FAI defines spaceflight to begin. To help compare orders of magnitude, this section lists lengths between 100 and 1,000 kilometres (10 and 10 metres). A distance of 100 kilometres is equal to about 62 miles (or ). To help compare different orders of magnitude"
"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"
"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"
"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"
"is roughly equal to the time in minutes from the station, at the current ground speed. 1 in 60 rule In air navigation, the 1 in 60 rule is a rule of thumb which states that if a pilot has travelled sixty miles then an error in track of one mile is approximately a 1° error in heading, and proportionately more for larger errors. The rule is used by single pilots with many other tasks to perform, often in a basic aircraft without the aid of an autopilot, who need a simple process that can be performed in their heads."
"Knot (unit) The knot () is a unit of speed equal to one nautical mile per hour, exactly (approximately ). The ISO standard symbol for the knot is . The same symbol is preferred by the Institute of Electrical and Electronics Engineers (IEEE); is also common, especially in aviation where it is the form recommended by the International Civil Aviation Organization (ICAO). The knot is a non-SI unit. Worldwide, the knot is used in meteorology, and in maritime and air navigation—for example, a vessel travelling at 1 knot along a meridian travels approximately one minute of geographic latitude in one"
"conditions. Knot (unit) The knot () is a unit of speed equal to one nautical mile per hour, exactly (approximately ). The ISO standard symbol for the knot is . The same symbol is preferred by the Institute of Electrical and Electronics Engineers (IEEE); is also common, especially in aviation where it is the form recommended by the International Civil Aviation Organization (ICAO). The knot is a non-SI unit. Worldwide, the knot is used in meteorology, and in maritime and air navigation—for example, a vessel travelling at 1 knot along a meridian travels approximately one minute of geographic latitude 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"
"To compare different orders of magnitude this section lists lengths between 100 metres and 1000 metres (1 kilometre). 100 metres (sometimes termed a hectometre) is equal to: To help compare different orders of magnitude this section lists lengths between 1 kilometre and 10 kilometres (10 and 10 metres). 1 kilometre (unit symbol km) is equal to: To help compare different orders of magnitude this section lists lengths between 10 and 100 kilometres (10 to 10 metres). The ""myriametre"" (sometimes also spelled ""myriameter"", ""myriometre"" and ""myriometer"") (10,000 metres) is a deprecated unit name; the decimal metric prefix myria- (sometimes also written"
"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"
"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"
"arcsecond on a 10 m class telescope. Minutes (′) and seconds (″) of arc are also used in cartography and navigation. At sea level one minute of arc along the equator or a meridian (indeed, any great circle) equals exactly one geographical mile along the Earth's equator or approximately one nautical mile (1852 meters, or ≈1.15078 statute miles). A second of arc, one sixtieth of this amount, is roughly 30 meters or 100 feet. The exact distance varies along meridian arcs because the figure of the Earth is slightly oblate (bulges a third of a percent at the equator). Positions"
"ten thousand kilometres), was determined in the late 20th century by space satellites to be 10,002,290 meters. This small error of 2,290 meters equals 1.423 statute miles; the error in such a large measurement amounts to 14½ inches per statute mile. It represents in each meter an error of approximately 0.23 millimetres – slightly more than the width of a single strand of human hair. This discrepancy is sometimes mentioned as ""Méchain's error"", with the suggestion that the tiny variation in the length of the meridian (not detected for nearly two hundred years) can be attributed to Méchain's calculations. But"
"Lunar distance (navigation) In celestial navigation, lunar distance is the angular distance between the Moon and another celestial body. The lunar distances method uses this angle, also called a lunar, and a nautical almanac to calculate Greenwich time. That calculated time can be used in solving a spherical triangle. The method was published in 1763 and used until about 1850 when it was superseded by the marine chronometer. A similar method uses the positions of the Galilean moons of Jupiter. In celestial navigation, knowledge of the time at Greenwich and the measured positions of one or more celestial objects allows"
"or up to 800 miles (using the 100m-per-square scale). The cherub with the dividers suggests how a navigator is supposed to use the grid to calculate alargar and avanzar by visual measurement rather than manipulating numbers. Example: suppose the ship has travelled 120 miles at two quarter-winds below the intended course (e.g. traveled at ESE, when the intended course is East). Using the dividers and the 20m scale, the navigator can measure out 120 miles with his dividers. Then setting one end at the top left corner (""A""), he lays out the dividers along the ESE ray (= two quarter-winds"
"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"
"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"
"per knot. Although the unit ""knot"" does not fit within the SI system, its retention for nautical and aviation use is important because the length of a nautical mile, upon which the knot is based, is closely related to the size of the Earth. As a result, nautical miles and knots are convenient units to use when navigating an aircraft or ship. Standard nautical charts are on the Mercator projection and the horizontal (East-West) scale varies with latitude. On a chart of the North Atlantic, the scale varies by a factor of two from Florida to Greenland. A single graphic"
"consults the home port clock, every hour's discrepancy between them translates into another fifteen degrees of longitude. One degree of longitude equals four minutes of time the world over, although in terms of distance, one degree shrinks from 60.15 nautical miles or 111 km [Earth's circumference being: 21,653.521 nautical miles, or 24,901.55 statute miles at the Equator], to virtually nothing at the poles. Precise knowledge of the hour in two different places at once - a longitude prerequisite so easily accessible today from any pair of cheap wristwatches - was utterly unattainable up to and including the era of pendulum"
"Measures recognises that NM, Nm and nmi are also in use. The word mile is from the Latin word for a thousand paces: mille passus. Navigation at sea was done by eye until around 1500 when navigational instruments were developed and cartographers began using a coordinate system with parallels of latitude and meridians of longitude. In 1617 the Dutch scientist Willebrord Snell assessed the circumference of the Earth at 24,630 Roman miles (24,024 statute miles). Around that time British mathematician Edmund Gunter improved navigational tools including a new quadrant to determine latitude at sea. He reasoned that the lines of"
"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 ="
"gigametres (Gm) or 10 million kilometres, or 0.07 Astronomical units). To help compare distances at different orders of magnitude this section lists lengths starting at 10 metres (100 Gm or 100 million kilometres or 0.7 astronomical units). To help compare different distances, this section lists lengths starting at 10 m (1 Tm or 1 billion km or 6.7 astronomical units). To help compare different distances this section lists lengths starting at 10 m (10 Tm or 10 billion km or 67 astronomical units). To help compare different distances this section lists lengths starting at 10 m (100 Tm or 100"
"Metre The metre (British spelling and BIPM spelling) or meter (American spelling) (from the French unit ""mètre"", from the Greek noun μέτρον, ""measure"") is the base unit of length in some metric systems, including the International System of Units (SI). The SI unit symbol is m. The metre is defined as the length of the path travelled by light in a vacuum in second. The metre was originally defined in 1793 as one ten-millionth of the distance from the equator to the North Pole – as a result the Earth's circumference is approximately 40,000 km today. In 1799, it was"
"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 geographical mile is based upon the length of a meridian"
"10 m (1 Em or 105.7 light years) and 10 m (1057 light years). To help compare different orders of magnitude, this section lists distances starting at 10 Em (10 m or 1,100 light years). To help compare different orders of magnitude, this section lists distances starting at 100 Em (10 m or 11,000 light years). The zettametre (SI symbol: Zm) is a unit of length in the metric system equal to 10 metres. To help compare different orders of magnitude, this section lists distances starting at 1 Zm (10 m or 110,000 light years). To help compare different orders"
"the ellipsoid varies with latitude, being the longest at the pole and the shortest at the equator as is the nautical mile. A metre was originally defined as the 10-millionth part of the length from equator to North Pole along the meridian through Paris (the target was not quite reached in actual implementation, so that is off by 200 ppm in the current definitions). This means that one kilometre is roughly equal to (1/40,000) * 360 * 60 meridional minutes of arc, which equals 0.54 nautical mile, though this is not exact because the two units are defined on different"
"this section lists lengths starting at 10 m (1 Mm or 1,000 km). 1 megametre is equal to: To help compare different orders of magnitude, this section lists lengths starting at 10 metres (10 megametres or 10,000 kilometres). 10 megametres (10 Mm) is To help compare different orders of magnitude, this section lists lengths starting at 10 metres (100 megametres or 100,000 kilometres or 62,150 miles). To help compare different distances this section lists lengths starting at 10 metres (1 gigametre (Gm) or 1 billion metres). To help compare different distances this section lists lengths starting at 10 metres (10"
"Parsec The parsec (symbol: pc) is a unit of length used to measure large distances to astronomical objects outside the Solar System. A parsec is defined as the distance at which one astronomical unit subtends an angle of one arcsecond, which corresponds to astronomical units. One parsec is equal to about 3.26 light-years (30 trillion km or 19 trillion miles) in length. The nearest star, Proxima Centauri, is about from the Sun. Most of the stars visible to the unaided eye in the night sky are within 500 parsecs of the Sun. The parsec unit was probably first suggested in"
"based on a fresh water density of 62.4 lb/ft and for fsw based on a sea water density of 64.0 lb/ft. One standard metre sea water equals: One standard metre sea water is also approximately equal to: One standard foot sea water is approximately equal to: Metre sea water The metre (or meter) sea water (msw) is a unit of pressure used in underwater diving. It is defined as one tenth of a bar. The unit used in the US is the foot sea water (fsw), based on standard gravity and a sea-water density of 64 lb/ft. According to the"