7001,Airy 1830,,6377563.396,9001,299.3249646,,1995-06-02 00:00:00,Ordnance Survey of Great Britain.,EPSG,Original definition is a=20923713 and b=20853810 feet of 1796. For the 1936 retriangulation OSGB defines the relationship of feet of 1796 to the International metre through log(1.48401603) exactly [=0.3048007491...]. 1/f is given to 7 decimal places.,98.321 98.34
7002,Airy Modified 1849,,6377340.189,9001,299.3249646,,1995-06-02 00:00:00,,EPSG,OSGB Airy 1830 figure rescaled by 1.000035 to best fit the primary triangulation of Ireland.,98.321
7003,Australian National Spheroid,,6378160.0,9001,298.25,,1995-06-02 00:00:00,"\"Australian Map Grid Technical Manual\"; National Mapping Council of Australia Special Publication #7; 1972",EPSG,Based on the GRS 1967 figure but with 1/f taken to 2 decimal places exactly.,
7004,Bessel 1841,,6377397.155,9001,299.1528128,,1999-04-22 00:00:00,US Army Map Service Technical Manual; 1943.,EPSG,"Original 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.",98.321 98.34
7005,Bessel Modified,,6377492.018,9001,299.1528128,,1999-04-22 00:00:00,,EPSG,Used in Norway and also in Sweden with a 1mm increase in semi-major axis.,98.321
7006,Bessel Namibia,,6377483.865,9001,299.1528128,,1999-04-22 00:00:00,,EPSG,a = 6377397.155 German legal metres. This is the same value as the Bessel 1841 figure (code 7004) but in different units. Used in Namibia.,97.16
7007,Clarke 1858,,20926348.0,9005,,20855233.0,1995-06-02 00:00:00,"\"Ellipsoidisch Parameter der Erdfigur (1800-1950)\" by Georg Strasser.",EPSG,Clarke's 1858/II solution. Derived parameters: a = 6378293.645m using his 1865 ratio of 0.304797265 feet per metre; 1/f = 294.26068à In historic usage in Australia 1/f taken to two decimal places (294.26 exactly); elsewhere a and b used to derive 1/f.,99.70
7008,Clarke 1866,,6378206.4,9001,,6356583.8,1995-06-02 00:00:00,US Army Map Service Technical Manual No. 7; 1943.,EPSG,Original 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 United States using 39.37 exactly giving a=20925832.16 ft US).,98.34
7009,Clarke 1866 Michigan,,20926631.531,9003,,20855688.674,1995-06-02 00:00:00,USGS Professional Paper #1395.,EPSG,Used for Michigan NAD27 State Plane zones. Radius = ellipsoid radius + 800 feet; this approximates the average elevation of the state. Derived parameter: 1/f = 294.97870,98.22
7010,Clarke 1880 (Benoit),,6378300.789,9001,,6356566.435,1995-06-02 00:00:00,,EPSG,Adopts Clarke's values for a and b. Uses Benoit's 1895 ratio of 0.9143992 metres per yard to convert to metres.,
7011,Clarke 1880 (IGN),,6378249.2,9001,,6356515.0,1998-04-16 00:00:00,,EPSG,Adopts Clarke's values for a and b using his 1865 ratio of 39.370432 inches per metre to convert axes to metres.,98.12
7012,Clarke 1880 (RGS),,6378249.145,9001,293.465,,1995-06-02 00:00:00,Empire Survey Review #32; 1939.,EPSG,Adopts 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.,
7013,Clarke 1880 (Arc),,6378249.145,9001,293.4663077,,1999-04-22 00:00:00,,EPSG,Adopts 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.,
7014,Clarke 1880 (SGA 1922),,6378249.2,9001,293.46598,,1995-06-02 00:00:00,,EPSG,Used in Old French Triangulation (ATF). Uses Clarke's 1865 inch-metre ratio of 39.370432 to convert axes to metres.,
7015,Everest 1830 (1937 Adjustment),,6377276.345,9001,300.8017,,1996-10-18 00:00:00,Survey of India professional paper #28; 1939,EPSG,Used 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/f,96.20
7016,Everest 1830 (1967 Definition),,6377298.556,9001,300.8017,,1995-06-02 00:00:00,,EPSG,Adopted 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.,
7018,Everest 1830 Modified,,6377304.063,9001,300.8017,,1995-06-02 00:00:00,,EPSG,Adopted 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.,
7019,GRS 1980,,6378137.0,9001,298.257222101,,1998-11-11 00:00:00,"\"Geodetic Reference System 1980\" by H. Moritz; Bulletin Geodesique",EPSG,Adopted by IUGG 1979 Canberra. Inverse flattening is derived from geocentric gravitational constant GM = 3986005e8 m*m*m/s/s; dynamic form factor J2 = 108263e8 and Earth's angular velocity = 7292115e-11 rad/s.,98.11 98.32
7020,Helmert 1906,,6378200.0,9001,298.3,,1995-06-02 00:00:00,"\"Ellipsoidisch Parameter der Erdfigur (1800-1950)\" by Georg Strasser",EPSG,Helmert 1906/III solution.,
7021,Indonesian National Spheroid,,6378160.0,9001,298.247,,1995-06-02 00:00:00,Rais paper.,EPSG,Based on the GRS 1967 figure but with 1/f taken to 3 decimal places exactly.,
7022,International 1924,,6378388.0,9001,297.0,,1995-06-02 00:00:00,,EPSG,Adopted by IUGG 1924 in Madrid. Based on Hayford 1909/1910 figures.,
7025,NWL 9D,,6378145.0,9001,298.25,,1995-06-02 00:00:00,,EPSG,Used by Transit Precise Ephemeris between October 1971 and January 1987.,
7027,Plessis 1817,,6376523.0,9001,308.64,,1995-06-02 00:00:00,"IGN Paris \"Constants d'Ellipsoides\" February 1972.",EPSG,Rescaling of Delambre 1810 figure (a=6376985 m) to make meridional arc from equator to pole equal to 10000000 metres exactly. (Ref: Strasser).,
7028,Struve 1860,,6378298.3,9001,294.73,,1998-11-11 00:00:00,"\"Geodesia y Cartografia Matematica\" by Fernando Martin Asin; ISBN 84-398-0248-X.",EPSG,"Original 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.",98.07 98.34
7030,WGS 84,,6378137.0,9001,298.257223563,,1998-11-11 00:00:00,DMA Technical Manual 8350.2-B,EPSG,Inverse flattening derived from four defining parameters (semi-major axis; C20 = -484.16685*10e-6; earth's angular velocity w = 7292115e11 rad/sec; gravitational constant GM = 3986005e8 m*m*m/s/s).,98.32
7031,GEM 10C,,6378137.0,9001,298.257223563,,1995-06-02 00:00:00,,EPSG,Used for GEM 10C Gravity Potential Model.,98.32
7032,OSU86F,,6378136.2,9001,298.257223563,,1995-06-02 00:00:00,,EPSG,Used for OSU86 gravity potential (geoidal) model.,98.32
7033,OSU91A,,6378136.3,9001,298.257223563,,1995-06-02 00:00:00,,EPSG,Used for OSU91 gravity potential (geoidal) model.,98.32
7034,Clarke 1880,,20926202.0,9005,293.465,20854895.0,1995-06-02 00:00:00,"\"Ellipsoidisch Parameter der Erdfigur (1800-1950)\" by Georg Strasser.",EPSG,Clarke gave a and b and also 1/f=293.465 (to 3 decimal places). 1/f derived from a and b = 293.4663077à,
7035,Sphere,,6371000.0,9001,,6371000.0,1995-06-02 00:00:00,,EPSG,Authalic sphere. 1/f is infinite.,
7036,GRS 1967,,6378160.0,9001,298.247167427,,1998-11-11 00:00:00,"\"Geodetic Reference System 1967\"; International Association of Geodesy special publication number 3; August 1971.",EPSG,Adopted by IUGG 1967 Lucerne. Inverse flattening 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.,96.09 97.252 98.32
7041,Average Terrestrial System 1977,,6378135.0,9001,298.257,,1997-07-22 00:00:00,New Brunswick Geographic Information Corporation land and water information standards manual,EPSG,,98.321
7042,Everest (1830 Definition),,20922931.8,9080,300.8017,20853374.58,1999-10-20 00:00:00,"\"Ellipsoidisch Parameter der Erdfigur (1800-1950)\" by Georg Strasser",EPSG,Everest gave a and b to 2 decimal places and also 1/f=300.8017 (to 4 decimal places).,97.23
7044,Everest 1830 (1962 Definition),,6377301.243,9001,300.8017255,,1999-10-20 00:00:00,,EPSG,Used 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.,
7045,Everest 1830 (1975 Definition),,6377299.151,9001,300.8017255,,1999-10-20 00:00:00,,EPSG,Used 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.,