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In geodesy, the Hayford ellipsoid is a reference ellipsoid named after the American geodesist John Fillmore Hayford (1868–1925), which was introduced in 1910. The Hayford ellipsoid was also referred to as the International ellipsoid 1924 after it had been adopted by the International Union of Geodesy and Geophysics IUGG in 1924, and was recommended for use all over the world. Many countries retained their previous ellipsoids.
The Hayford ellipsoid is defined by its semi-major axis a = 6378388.000 m and its flattening f = 1:297.00. Unlike some of its predecessors, such as the Bessel ellipsoid (a = 6377397 m, f = 1:299.15), which was a European ellipsoid, the Hayford ellipsoid also included measurements from North America, as well as other continents (to a lesser extent). It also included isostatic measurements to reduce plumbline divergences. Hayfords ellipsoid did not reach the accuracy of Helmert's ellipsoid published 1906 (a = 6378200 m, f = 1:298.3).
It has since been replaced as the "International ellipsoid" by the newer Lucerne ellipsoid (1967) and GRS 80 (1980).
In geodesy, the Hayfordellipsoid is a reference ellipsoid named after the American geodesist John Fillmore Hayford (1868–1925), which was introduced...
Bessel ellipsoid of 1841, the international Hayfordellipsoid of 1924, and (for GPS positioning) the WGS84 ellipsoid. There are two types of ellipsoid: mean...
Clarke ellipsoid of 1880. After the arrival of the geophysical reduction techniques many projects used other examples such as the Hayfordellipsoid of 1910...
isostasy and the construction of a reference ellipsoid for approximating the figure of the Earth. Hayford was elected to the United States National Academy...
initial members of the International Statistical Institute. Until Hayfordellipsoid was calculated in 1910, vertical deflections were considered as random...
axis (equatorial radius) of the Hayfordellipsoid and that of the modern WGS84 ellipsoid is 251 m; for Helmert's ellipsoid it is only 63 m. A more recent...
In the mid-1800s the Bessel ellipsoid of 1841 or the Clarke ellipsoid of 1866 were widely used; the Hayfordellipsoid of 1910 may later have been used...
normally refers to the Bessel ellipsoid. A further datum of interest was ED50 (European Datum 1950) based on the Hayfordellipsoid. ED50 was part of the fundamentals...
which have their own datums. It used the International Ellipsoid of 1924 ("Hayford-Ellipsoid" of 1909) (radius of the Earth's equator 6378.388 km, flattening...
International Geodesy), and a series of global ellipsoids of the Earth were derived (e.g., Helmert 1906, Hayford 1910/ 1924). A unified geodetic system for...
and a Scale Factor at Origin (mo) = 0.9998. The JTM is based on the Hayfordellipsoid adopted by the IUGG in 1924. No transformation parameters are presently...
Earth, the reference ellipsoid is the International Reference Ellipsoid, and the value of gravity predicted for points on the ellipsoid is the normal gravity...
global ellipsoid in 1906 with an accuracy of 100 meters (0.002 percent of the Earth's radii). The US geodesist Hayford derived a global ellipsoid in ~1910...
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