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1ellipsoid_codeellipsoid_namesemi_major_axisuom_codeinv_flatteningsemi_minor_axisellipsoid_shaperemarksinformation_sourcedata_sourcerevision_datechange_iddeprecated
21024CGCS200063781379001298.2572221011Defining parameters semi-major axis, flattening and angular velocity are same as for GRS 1980 (ellipsoid code 7019); GM = 3986004.4e8 m*m*m/s/s (from NASA 1986 Lageos determination).Chinese Academy of Surveying and Mapping.OGP2009/11/122009.0840
31025GSK-20116378136.59001298.25641511Parametry Zemli 1990 Reference Document, Military Topgraphic Department (VTU) of the General Staff of Armed Forces of the Russian Federation.IOGP2016/01/252015.0550
47001Airy 18306377563.3969001299.32496461Original definition is a=20923713, b=20853810 feet of 1796. 1/f is given to 7 decimal places. For the 1936 retriangulation OSGB defines the relationship of 10 feet of 1796 to the International metre through ([10^0.48401603]/10) exactly = 0.3048007491...Ordnance Survey of Great Britain.OGP2006/11/271998.321 1998.340 2006.9320
57002Airy Modified 18496377340.1899001299.32496461OSGB Airy 1830 figure (ellipsoid code 7001) rescaled by 0.999965 to best fit the scale of the 19th century primary triangulation of Ireland."The Irish Grid - A Description of the Co-ordinate Reference System" published by Ordnance Survey of Ireland, Dublin and Ordnance Survey of Northern Ireland, Belfast.OGP2003/06/271998.321 2002.6220
67003Australian National Spheroid63781609001298.251Based on the GRS 1967 figure but with 1/f taken to 2 decimal places exactly. The dimensions are also used as the GRS 1967 Modified ellipsoid (see code 7050)."Australian Map Grid Technical Manual"; National Mapping Council of Australia Special Publication #7; 1972OGP2008/08/112002.500 2008.0170
77004Bessel 18416377397.1559001299.15281281Original Bessel definition is a=3272077.14 and b=3261139.33 toise. This used a weighted mean of values from several authors but did not account for differences in the length of the various toise: the "Bessel toise" is therefore of uncertain length.US Army Map Service Technical Manual; 1943.OGP1999/04/221998.321 1998.3400
87005Bessel Modified6377492.0189001299.15281281Used in Norway and also in Sweden with a 1mm increase in semi-major axis.OGP1999/04/221998.3210
97006Bessel Namibia6377483.8659001299.15281281a = 6377397.155 German legal metres. This is the same value as the Bessel 1841 figure (code 7004) but in different units. Used in Namibia.Chief Directorate: Surveys and Mapping, Mowbray, South Africa.OGP1999/04/221997.1601
107007Clarke 1858209263489005208552331Clarke's 1858/II solution. Derived parameters: a = 6378293.645m using his 1865 ratio of 0.3047972654 feet per metre; 1/f = 294.26068… In Australia and Amoco Trinidad 1/f taken to two decimal places (294.26 exactly); elsewhere a and b used to derive 1/f."Ellipsoidisch Parameter der Erdfigur (1800-1950)" by Georg Strasser.OGP2005/08/141999.700 2005.3700
117008Clarke 18666378206.490016356583.81Original definition a=20926062 and b=20855121 (British) feet. Uses Clarke's 1865 inch-metre ratio of 39.370432 to obtain metres. (Metric value then converted to US survey feet for use in the US and international feet for use in Cayman Islands).US Army Map Service Technical Manual No. 7; 1943.OGP2013/01/171998.340 2012.0950
127009Clarke 1866 Michigan20926631.531900320855688.6741Used for Michigan NAD27 State Plane zones. Radius = ellipsoid radius + 800 feet; this approximates the average elevation of the state. Derived parameter: 1/f = 294.97870USGS Professional Paper #1395.OGP1995/06/021998.220 2013.0201
137010Clarke 1880 (Benoit)6378300.78990016356566.4351Adopts Clarke's values for a and b. Uses Benoit's 1895 ratio of 0.9143992 metres per yard to convert to metres.OGP1995/06/020
147011Clarke 1880 (IGN)6378249.2900163565151Adopts Clarke's values for a and b using his 1865 ratio of 39.370432 inches per metre to convert axes to metres.OGP1998/04/161998.1200
157012Clarke 1880 (RGS)6378249.1459001293.4651Adopts Clarke's values for a and 1/f. Adopts his 1865 ratio of 39.370432 inches per metre to convert semi-major axis to metres. Also known as Clarke Modified 1880.Empire Survey Review #32; 1939.OGP1995/06/020
167013Clarke 1880 (Arc)6378249.1459001293.46630771Adopts Clarke's value for a with derived 1/f. Uses his 1865 ratio of 39.370432 inch per metre to convert semi-major axis to metres.Chief Directorate: Surveys and Mapping, Mowbray, South Africa.OGP2001/06/052001.0520
177014Clarke 1880 (SGA 1922)6378249.29001293.465981Used in Old French Triangulation (ATF). Uses Clarke's 1865 inch-metre ratio of 39.370432 to convert axes to metres.OGP1995/06/020
187015Everest 1830 (1937 Adjustment)6377276.3459001300.80171Used for the 1937 readjustment of Indian triangulation. Clarke's 1865 Indian-British foot ratio (0.99999566) and Benoit's 1898 British inch-metre ratio (39.370113) rounded as 0.30479841 exactly and applied to Everest's 1830 definition taken as a and 1/fSurvey of India professional paper #28; 1939OGP1996/10/181996.2000
197016Everest 1830 (1967 Definition)6377298.5569001300.80171Adopted 1967 for use in East Malaysia. Applies Sears 1922 inch-metre ratio of 39.370147 to Everest 1830 original definition of a and 1/f but with a taken to be in British rather than Indian feet.OGP1995/06/020
207018Everest 1830 Modified6377304.0639001300.80171Adopted 1967 for use in West Malaysia. Applies Benoit 1898 inch-metre ratio of 39.370113 to Everest 1830 original definition of a and 1/f but with a taken to be in British rather than Indian feet.OGP1995/06/020
217019GRS 198063781379001298.2572221011Adopted by IUGG 1979 Canberra. Inverse flattening is derived from geocentric gravitational constant GM = 3986005e8 m*m*m/s/s; dynamic form factor J2 = 108263e-8 and Earth's angular velocity = 7292115e-11 rad/s."Geodetic Reference System 1980" by H. Moritz; Bulletin GeodesiqueOGP2013/08/231998.110 1998.320 2013.0430
227020Helmert 190663782009001298.31Helmert 1906/III solution."Ellipsoidisch Parameter der Erdfigur (1800-1950)" by Georg StrasserOGP1995/06/020
237021Indonesian National Spheroid63781609001298.2471Based on the GRS 1967 figure but with 1/f taken to 3 decimal places exactly.Rais paper.OGP1995/06/020
247022International 1924637838890012971Adopted by IUGG 1924 in Madrid. Based on Hayford 1909/1910 figures. OGP1995/06/020
257024Krassowsky 194063782459001298.31OGP1995/06/020
267025NWL 9D63781459001298.251Used by Transit Precise Ephemeris between October 1971 and January 1987.OGP1995/06/020
277027Plessis 181763765239001308.641Rescaling of Delambre 1810 figure (a=6376985 m) to make meridional arc from equator to pole equal to 10000000 metres exactly. (Ref: Strasser).IGN Paris "Constants d'Ellipsoides" February 1972.OGP1995/06/020
287028Struve 18606378298.39001294.731Original definition of semi-major axis given as 3272539 toise. In "Ellipsoidisch Parameter der Erdfigur (1800-1950)" , Strasser suggests a conversion factor of 1.94903631 which gives a=6378297.337 metres."Geodesia y Cartografia Matematica" by Fernando Martin Asin; ISBN 84-398-0248-X.OGP1998/11/111998.070 1998.3400
297029War Office637830090012961In non-metric form, a=20926201 Gold Coast feet. DMA Technical Manual 8358.1 and data derived from this quotes value for semi-major axis as 6378300.58m: OGP recommends use of defined value 6378300m exactly.Tables for the use of the Gold Coast Survey Department, 1935.OGP2009/10/292009.0750
307030WGS 8463781379001298.25722356311/f derived from four defining parameters semi-major axis; C20 = -484.16685*10e-6; earth's angular velocity ? = 7292115e-11 rad/sec; gravitational constant GM = 3986005e8 m*m*m/s/s. In 1994 new GM = 3986004.418e8 m*m*m/s/s but a and 1/f retained.DMA Technical Manual 8350.2-BIOGP2015/11/251998.320 2015.0470
317031GEM 10C63781379001298.2572235631Used for GEM 10C Gravity Potential Model.OGP1995/06/021998.3200
327032OSU86F6378136.29001298.2572235631Used for OSU86 gravity potential (geoidal) model.OGP1995/06/021998.3200
337033OSU91A6378136.39001298.2572235631Used for OSU91 gravity potential (geoidal) model.OGP1995/06/021998.3200
347034Clarke 1880209262029005208548951Clarke gave a and b and also 1/f=293.465 (to 3 decimal places exactly). In the 19th century b was normally given as the second defining parameter."Ellipsoidisch Parameter der Erdfigur (1800-1950)" by Georg Strasser.OGP2008/06/262008.0570
357035Sphere6371000900163710000Authalic sphere. 1/f is infinite. Superseded by GRS 1980 authalic sphere (code 7047).OGP1995/06/021
367036GRS 196763781609001298.2471674271Adopted by IUGG 1967 Lucerne. 1/f given is derived from geocentric gravitational constant (GM)= 398603e9 m*m*m/s/s; dynamic form factor (J2) = 0.0010827 and Earth's angular velocity w = 7.2921151467e-5 rad/s. See also GRS 1967 Modified (code 7050)."Geodetic Reference System 1967"; International Association of Geodesy special publication number 3; August 1971.OGP2011/02/251996.090 1997.252 1998.320 2002.500 2011.0160
377041Average Terrestrial System 197763781359001298.2571New Brunswick Geographic Information Corporation land and water information standards manualOGP1997/07/221998.3210
387042Everest (1830 Definition)20922931.8908020853374.581Everest gave a and b to 2 decimal places and also 1/f=300.8017 (to 4 decimal places exactly). In the 19th century b was normally given as the second defining parameter."Ellipsoidisch Parameter der Erdfigur (1800-1950)" by Georg StrasserOGP2008/06/261997.231 2008.0570
397043WGS 7263781359001298.261OGP1999/04/221999.0300
407044Everest 1830 (1962 Definition)6377301.2439001300.80172551Used by Pakistan since metrication. Clarke's 1865 Indian foot-British foot ratio (0.99999566) and his 1865 British inch-metre ratio (39.369971) rounded with slight error as 1 Ind ft = 0.3047995m exactly and applied to Everest's 1830 definition of a & b.OGP1999/10/200
417045Everest 1830 (1975 Definition)6377299.1519001300.80172551Used by India since metrication. Clarke's 1865 Indian foot-British foot ratio (0.99999566) and his 1865 British inch-metre ratio (39.369971) rounded as 1 Ind ft = 0.3047995m exactly applied to Everest's 1830 original definition taken as a and b.OGP1999/10/200
427046Bessel Namibia (GLM)6377397.1559031299.15281281The semi-major axis has the same value as the Bessel 1841 ellipsoid (code 7004) but is in different units - German Legal Metres rather than International metres - hence a different size. a = 6377483.865 International metres. Used in Namibia.Chief Directorate: Surveys and Mapping, Mowbray, South Africa.OGP2007/09/212007.0910
437047GRS 1980 Authalic Sphere6370997900163709970Authalic sphere derived from Clarke 1866 ellipsoid (code 7008). Deprecated as name and parameter values do not match; replaced by 7048.OGPOGP2001/06/051
447048GRS 1980 Authalic Sphere6371007900163710070Authalic sphere derived from GRS 1980 ellipsoid (code 7019). (An authalic sphere is one with a surface area equal to the surface area of the ellipsoid). 1/f is infinite.OGPOGP2001/06/250
457049IAG 197563781409001298.2571Chinese Sceience Bulletin, 2009, 54:2714-2721.OGP2009/11/242009.0840
467050GRS 1967 Modified63781609001298.251Based on the GRS 1967 figure (code 7036) but with 1/f taken to 2 decimal places exactly. Used with SAD69 and TWD67 datums. The dimensions are also used as the Australian National Spheroid (code 7003)."Geodetic Reference System 1967"; International Association of Geodesy special publication number 3; August 1971.OGP2008/08/112008.0170
477051Danish 18766377019.2790013001Semi-major axis originally given as 3271883.25 toise. Uses toise to French metre ratio of 1.94903631 to two decimal place precision. An alternative ratio with the German legal metre of 1.9490622 giving 6377104m has not been used in Danish work.Kort og Matrikelstyrelsen (KMS), Copenhagen.OGP2003/06/270
487052Clarke 1866 Authalic Sphere6370997900163709970Authalic sphere derived from Clarke 1866 ellipsoid (code 7008).OGPOGP2004/04/270
497053Hough 1960637827090012971DMA / NIMA / NGA TR8350.2OGP2006/01/260
507054PZ-9063781369001298.2578393031Earth's angular velocity ? = 7.292115e-5 rad/sec; gravitational constant GM = 3986004.418e8 m*m*m/s/s.Parametry Zemli 1990 Reference Document, Military Topgraphic Department (VTU) of the General Staff of Armed Forces of the Russian Federation.IOGP2016/12/152015.0550
517055Clarke 1880 (international foot)209262029002208548951Clark'es 1880 definition in feet assumed for the purposes of metric conversion to be international foot. a = 6378306.370…metres. 1/f derived from a and b = 293.4663077… Used in Fiji.Department of Lands and Survey, Fiji.OGP2006/07/140
527056Everest 1830 (RSO 1969)6377295.6649001300.80171Adopted for 1969 metrication of peninsula Malaysia RSO grid. Uses Sears 1922 yard-metre ratio truncated to 6 significant figures applied to Everest 1830 original definition of a and 1/f but with a taken to be in British rather than Indian feet.Defence Geographic CentreOGP2006/07/240
537057International 1924 Authalic Sphere6371228900163712280Authalic sphere derived from International 1924 ellipsoid (code 7022).OGPOGP2006/09/220
547058Hughes 1980637827390016356889.4491Used in US DMSP SSM/I microwave sensor processing software. Semi-minor axis derived from eccentricity=0.081816153. Semi-major axis (a) sometimes given as 3443.992nm which OGP suspects is a derived approximation. OGP conversion assumes 1nm=1852m exactly.US National Snow and Ice Data CenterOGP2006/09/220
557059Popular Visualisation Sphere6378137900163781370Sphere with radius equal to the semi-major axis of the GRS80 and WGS 84 ellipsoids. Used only for Web approximate mapping and visualisation. Not recognised by geodetic authorities.Microsoft.OGP2008/03/142008.1141