Ellipsoid_Name Ellipsoid_Code Semi-Major_Axis_a Semi-Minor_Axis_b Inverse_Flattening_rf Length_Unit_Code Length_Unit_Name Information_Source Remarks Revision_Date name code - - - UNITS.code UNITS.name - - - Airy 1830 7001 6377563.396 299.32496 9001 metre Original definition of a and b in feet. OSGB defines 1/f to 7 d.p. 02-Jun-95 Airy Modified 1849 7002 6377340.189 299.32496 9001 metre 02-Jun-95 Australian National Spheroid 7003 6378160 298.25 9001 metre Australian Map Grid Technical Manual. National Mapping Council of Australia Special Publication 7; 1972. 02-Jun-95 Bessel 1841 7004 6377397.155 299.15281 9001 metre 02-Jun-95 Bessel Modified 7005 6377492.018 299.15281 9001 metre 02-Jun-95 Bessel Namibia 7006 6377483.865 299.15281 9001 metre 02-Jun-95 Clarke 1858 7007 20926348 20855233 9005 Clarke's foot """Ellipsoidisch Parameter der Erdfigur (1800-1950)"" by Georg Strasser" Clarke 1858/II solution. Derived parameters: a = 6378293.639m; 1/f = 294.26068 02-Jun-95 Clarke 1866 7008 6378206.4 6356583.8 9001 metre Uses Benoit 1896 foot-metre ratio. Derived parameter: 1/f = 294.97870 02-Jun-95 Clarke 1866 Michigan 7009 20926631.53 20855688.67 9004 Modified American foot USGS Professional Paper #1395 Used for Michigan old T.M. S.P. zones. Derived parameters: 1/f = 294.97870 02-Jun-95 Clarke 1880 7034 20926202 20854895 9005 Clarke's foot """Ellipsoidisch Parameter der Erdfigur (1800-1950)""by Georg Strasser""." Derived parameter: 1/f = 293.46631 02-Jun-95 Clarke 1880 (Arc) 7013 6378249.145 293.46631 9001 metre 02-Jun-95 Clarke 1880 (Benoit) 7010 6378300.79 6356566.43 9001 metre Uses Benoit 1896 inch-metre ratio. Derived parameter: 1/f = 293.46623 02-Jun-95 Clarke 1880 (IGN) 7011 6378249.2 293.46602 9001 metre 02-Jun-95 Clarke 1880 (RGS) 7012 6378249.145 293.465 9001 metre 02-Jun-95 Clarke 1880 (SGA 1922) 7014 6378249.2 293.46598 9001 metre Used in Old French Triangulation (ATF). 02-Jun-95 Everest 1830 (1937 Adjustment) 7015 6377276.345 300.8017 9001 metre Used for the 1937 adjustment of Indian triangulation 02-Jun-95 Everest 1830 (1967 Definition) 7016 6377298.556 300.8017 9001 metre Adopted 1967 for use in East Malaysia. Uses Sears 1928 inch-metre ratio. 02-Jun-95 Everest 1830 (1975 Definition) 7017 6377301.243 6356100.231 9001 metre Used by Surveys of India and Pakistan since 1975. Derived parameter: 1/f = 300.80174 02-Jun-95 Everest 1830 Modified 7018 6377304.063 300.8017 9001 metre Adopted 1967 for use in West Malaysia. Uses Benoit 1898 inch-metre ratio. 02-Jun-95 GEM 10C 7031 6378137 298.25722 9001 metre Used for GEM 10C Gravity Potential Model. 02-Jun-95 GRS 1980 7019 6378137 298.25722 9001 metre Adopted by IUGG 1979 Canberra. 02-Jun-95 Helmert 1906 7020 6378200 298.3 9001 metre """Ellipsoidisch Parameter der Erdfigur (1800-1950)"" by Georg Strasser" Helmert 1906/III solution. 02-Jun-95 Indonesian National Spheroid 7021 6378160 298.247 9001 metre 02-Jun-95 International 1924 7022 6378388 297 9001 metre Adopted by IUGG 1924 in Madrid. Based on Hayford 1909/1910 figures. 02-Jun-95 International 1967 7023 6378160 298.25 9001 metre Adopted by IUGG 1967 Lucerne. Inverse flattening defined to 2 d.p. 02-Jun-95 Krassowsky 1940 7024 6378245 298.3 9001 metre 02-Jun-95 NWL 10D 7026 6378135 298.26 9001 metre Used by Transit Broadcast Ephemeris before 1989. Also referred to as WGS72 spheroid. 02-Jun-95 NWL 9D 7025 6378145 298.25 9001 metre Used by Transit Precise Ephemeris between October 1971 and January 1987. 02-Jun-95 OSU86F 7032 6378136.2 298.25722 9001 metre Used for OSU86 gravity potential (geoidal) model. 02-Jun-95 OSU91A 7033 6378136.3 298.25722 9001 metre Used for OSU91 gravity potential (geoidal) model. 02-Jun-95 Plessis 1817 7027 6376523 308.64 9001 metre "IGN Paris ""Constants d'Ellipsoides"" February 1972." 02-Jun-95 Sphere 7035 6371000 6371000 9001 metre Authalic sphere. 02-Jun-95 Struve 1860 7028 6378297 294.73 9001 metre 02-Jun-95 War Office 7029 6378300.583 296 9001 metre 02-Jun-95 WGS 84 7030 6378137 298.25722 9001 metre DMA Technical Manual 8350.2-B 02-Jun-95 7036