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Miners also use it as a unit of area equal to 6 feet square (3.34 m 2) in the plane of a vein. [2] In Britain, it can mean the quantity of wood in a pile of any length measuring 6 feet (1.8 m) square in cross section. [2] In Central Europe, the klafter was the corresponding unit of comparable length, as was the toise in France.
The international yard and pound agreement of July 1959 defined the length of the international yard in the United States and countries of the Commonwealth of Nations as exactly 0.9144 meters. Consequently, since a foot is one third of a yard, the international foot is defined to be equal to exactly 0.3048 meters.
Roman milestone in modern Austria (AD 201), indicating a distance of 28 Roman miles (~41 km) to Teurnia. The basic unit of Roman linear measurement was the pes (plural: pedes) or Roman foot. Investigation of its relation to the English foot goes back at least to 1647, when John Greaves published his Discourse on the Romane foot.
As the metre had to be equal to one ten-millionth of this distance, it was defined as 0.513074 toise or 3 feet and 11.296 lines of the Toise of Peru, which had been constructed in 1735 for the French Geodesic Mission to the Equator. When the final result was known, a bar whose length was closest to the meridional definition of the metre was ...
In ancient Rome, according to Vitruvius, a cubit was equal to 1 + 1 ⁄ 2 Roman feet or 6 palm widths (approximately 444 mm or 17 + 1 ⁄ 2 in). [23] A 120-centimetre cubit (approximately four feet long), called the Roman ulna, was common in the Roman empire, which cubit was measured from the fingers of the outstretched arm opposite the man's hip.
A nautical mile is a unit of length used in air, marine, and space navigation, and for the definition of territorial waters. [2] [3] [4] Historically, it was defined as the meridian arc length corresponding to one minute ( 1 / 60 of a degree) of latitude at the equator, so that Earth's polar circumference is very near to 21,600 nautical miles (that is 60 minutes × 360 degrees).
Shaku (Japanese: 尺) or Japanese foot[1][2] is a Japanese unit of length derived (but varying) from the Chinese chi, originally based upon the distance measured by a human hand from the tip of the thumb to the tip of the forefinger [3][a] (compare span). Traditionally, the length varied by location or use, but it is now standardized as 10/33 m ...
A geoid is needed to convert the 3D position to sea-level elevation. Pressure altimeter measuring atmospheric pressure, which decreases as altitude increases. Since atmospheric pressure varies with the weather, too, a recent local measure of the pressure at a known altitude is needed to calibrate the altimeter. Stereoscopy in aerial photography.