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Earth radius (denoted as R 🜨 or R E) is the distance from the center of Earth to a point on or near its surface. Approximating the figure of Earth by an Earth spheroid (an oblate ellipsoid), the radius ranges from a maximum (equatorial radius, denoted a) of nearly 6,378 km (3,963 mi) to a minimum (polar radius, denoted b) of nearly 6,357 km (3,950 mi).
The reverse conversion is harder: given X-Y-Z can immediately get longitude, but no closed formula for latitude and height exists. See "Geodetic system." Using Bowring's formula in 1976 Survey Review the first iteration gives latitude correct within 10-11 degree as long as the point is within 10,000 meters above or 5,000 meters below the ellipsoid.
The rounding of the Earth's radius to metres in GRS80 has an effect of 0.0001 m. The shape of the Earth is a slightly flattened sphere, which results in the Earth's circumference being 0.168% larger when measured around the equator as compared to through the poles.
A datum is a formal description of the shape of the Earth along with an "anchor" point for the coordinate system. In surveying , cartography , and land-use planning , two North American Datums are in use for making lateral or "horizontal" measurements: the North American Datum of 1927 (NAD 27) and the North American Datum of 1983 (NAD 83).
Unless specified otherwise, the radius of the Earth for the calculations below is: R {\displaystyle R\,\!} = 6,371.009 kilometers = 3,958.761 statute miles = 3,440.069 nautical miles . D {\displaystyle D_{\,}\!} = Distance between the two points, as measured along the surface of the Earth and in the same units as the value used for radius ...
A coordinate system conversion is a conversion from one coordinate system to another, with both coordinate systems based on the same geodetic datum. Common conversion tasks include conversion between geodetic and earth-centered, earth-fixed coordinates and conversion from one type of map projection to another.
Earth radius R 🜨 ≈ 6,371 km [14] Lunar distance LD ≈ 384 402 km. [15] Average distance between the center of Earth and the center of the Moon. astronomical unit au. Defined as 149 597 870 700 m. [16] Approximately the distance between the Earth and Sun. light-year ly ≈ 9 460 730 472 580.8 km.
The WGS 84 datum surface is an oblate spheroid with equatorial radius a = 6 378 137 m at the equator and flattening f = 1 ⁄ 298.257 223 563. The refined value of the WGS 84 gravitational constant (mass of Earth's atmosphere included) is GM = 3.986 004 418 × 10 14 m 3 /s 2. The angular velocity of the Earth is defined to be ω = 72.921 15 × ...