identifier |
description |
naming _system |
inverse _flattening |
semimajor _axis |
semiminor _axis |
source _reference |
source _content |
source |
version |
status |
|
|
naming _system .identifier |
|
|
|
|
|
|
ref _version .identifier |
|
Airy 1830 |
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. |
EPSG name |
299.3249646 |
6377563.396 m |
|
Ordnance Survey of Great Britain. |
EPSG |
POSC |
epicentre 2.1 |
current |
Airy Modified 1849 |
OSGB Airy 1830 figure rescaled by 1.000035 to best fit the primary triangulation of Ireland. |
EPSG name |
299.3249646 |
6377340.189 m |
|
|
EPSG |
POSC |
epicentre 2.1 |
current |
Australian National Spheroid |
Based on the GRS 1967 figure but with 1/f taken to 2 decimal places exactly. |
EPSG name |
298.25 |
6378160 m |
|
Australian Map Grid Technical Manual; National Mapping Council of Australia Special Publication #7; 1972 |
EPSG |
POSC |
epicentre 2.1 |
current |
Bessel 1841 |
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. |
EPSG name |
299.1528128 |
6377397.155 m |
|
US Army Map Service Technical Manual; 1943. |
EPSG |
POSC |
epicentre 2.1 |
current |
Bessel Modified |
Used in Norway and also in Sweden with a 1mm increase in semi-major axis. |
EPSG name |
299.1528128 |
6377492.018 m |
|
|
EPSG |
POSC |
epicentre 2.1 |
current |
Bessel Namibia |
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. |
EPSG name |
299.1528128 |
6377483.865 m |
|
|
EPSG |
POSC |
epicentre 2.1 |
current |
Clarke 1858 |
Clarke's 1858/II solution. Derived parameters: a = 6378293.645m using his 1865 ratio of 0.304797265 feet per metre; 1/f = 294.26068. In historic usage in Australia 1/f taken to two decimal places (294.26 exactly); elsewhere a and b used to derive 1/f. |
EPSG name |
|
20926348 ftCla |
20855233 ftCla |
Ellipsoidisch Parameter der Erdfigur (1800-1950) by Georg Strasser. |
EPSG |
POSC |
epicentre 2.1 |
current |
Clarke 1866 |
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). |
EPSG name |
|
6378206.4 m |
6356583.8 m |
US Army Map Service Technical Manual No. 7; 1943. |
EPSG |
POSC |
epicentre 2.1 |
current |
Clarke 1866 Michigan |
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 |
EPSG name |
|
20926631.53 ftUS |
20855688.67 ftUS |
USGS Professional Paper #1395. |
EPSG |
POSC |
epicentre 2.1 |
current |
Clarke 1880 (Benoit) |
Adopts Clarke's values for a and b. Uses Benoit's 1895 ratio of 0.9143992 metres per yard to convert to metres. |
EPSG name |
|
6378300.789 m |
6356566.435 m |
|
EPSG |
POSC |
epicentre 2.1 |
current |
Clarke 1880 (IGN) |
Adopts Clarke's values for a and b using his 1865 ratio of 39.370432 inches per metre to convert axes to metres. |
EPSG name |
|
6378249.2 m |
6356515 m |
|
EPSG |
POSC |
epicentre 2.2.2 |
current |
Clarke 1880 (RGS) |
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. |
EPSG name |
293.465 |
6378249.145 m |
|
Empire Survey Review #32; 1939. |
EPSG |
POSC |
epicentre 2.1 |
current |
Clarke 1880 (Arc) |
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. |
EPSG name |
293.4663077 |
6378249.145 m |
|
|
EPSG |
POSC |
epicentre 2.1 |
current |
Clarke 1880 (SGA 1922) |
Used in Old French Triangulation (ATF). Uses Clarke's 1865 inch-metre ratio of 39.370432 to convert axes to metres. |
EPSG name |
293.46598 |
6378249.2 m |
|
|
EPSG |
POSC |
epicentre 2.1 |
current |
Everest 1830 (1937 Adjustment) |
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 |
EPSG name |
300.8017 |
6377276.345 m |
|
Survey of India professional paper #28; 1939 |
EPSG |
POSC |
epicentre 2.1 |
current |
Everest 1830 (1967 Definition) |
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. |
EPSG name |
300.8017 |
6377298.556 m |
|
|
EPSG |
POSC |
epicentre 2.1 |
current |
Everest 1830 Modified |
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. |
EPSG name |
300.8017 |
6377304.063 m |
|
|
EPSG |
POSC |
epicentre 2.1 |
current |
GRS 1980 |
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. |
EPSG name |
298.2572221 |
6378137 m |
|
Geodetic Reference System 1980 by H. Moritz; Bulletin Geodesique |
EPSG |
POSC |
epicentre 2.1 |
current |
identifier |
description |
naming _system |
inverse _flattening |
semimajor _axis |
semiminor _axis |
source _reference |
source _content |
source |
version |
status |
Helmert 1906 |
Helmert 1906/III solution. |
EPSG name |
298.3 |
6378200 m |
|
Ellipsoidisch Parameter der Erdfigur (1800-1950) by Georg Strasser |
EPSG |
POSC |
epicentre 2.1 |
current |
Indonesian National Spheroid |
Based on the GRS 1967 figure but with 1/f taken to 3 decimal places exactly. |
EPSG name |
298.247 |
6378160 m |
|
Rais paper. |
EPSG |
POSC |
epicentre 2.1 |
current |
International 1924 |
Adopted by IUGG 1924 in Madrid. Based on Hayford 1909/1910 figures. |
EPSG name |
297 |
6378388 m |
|
|
EPSG |
POSC |
epicentre 2.1 |
current |
Krassowsky 1940 |
|
EPSG name |
298.3 |
6378245 m |
|
|
EPSG |
POSC |
epicentre 2.1 |
current |
NWL 9D |
Used by Transit Precise Ephemeris between October 1971 and January 1987. |
EPSG name |
298.25 |
6378145 m |
|
|
EPSG |
POSC |
epicentre 2.1 |
current |
Plessis 1817 |
Rescaling of Delambre 1810 figure (a=6376985 m) to make meridional arc from equator to pole equal to 10000000 metres exactly. (Ref: Strasser). |
EPSG name |
308.64 |
6376523 m |
|
IGN Paris Constants d'Ellipsoides February 1972. |
EPSG |
POSC |
epicentre 2.1 |
current |
Struve 1860 |
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. |
EPSG name |
294.73 |
6378298.3 m |
|
Geodesia y Cartografia Matematica by Fernando Martin Asin; ISBN 84-398-0248-X. |
EPSG |
POSC |
epicentre 2.1 |
current |
War Office |
|
EPSG name |
296 |
6378300.583 m |
|
|
EPSG |
POSC |
epicentre 2.1 |
current |
WGS 84 |
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). |
EPSG name |
298.2572236 |
6378137 m |
|
DMA Technical Manual 8350.2-B |
EPSG |
POSC |
epicentre 2.1 |
current |
GEM 10C |
Used for GEM 10C Gravity Potential Model. |
EPSG name |
298.2572236 |
6378137 m |
|
|
EPSG |
POSC |
epicentre 2.1 |
current |
OSU86F |
Used for OSU86 gravity potential (geoidal) model. |
EPSG name |
298.2572236 |
6378136.2 m |
|
|
EPSG |
POSC |
epicentre 2.1 |
current |
OSU91A |
Used for OSU91 gravity potential (geoidal) model. |
EPSG name |
298.2572236 |
6378136.3 m |
|
|
EPSG |
POSC |
epicentre 2.1 |
current |
Clarke 1880 |
Clarke gave a and b and also 1/f=293.465 (to 3 decimal places). 1/f derived from a and b = 293.4663077. |
EPSG name |
293.465 |
20926202 ftCla |
20854895 ftCla |
Ellipsoidisch Parameter der Erdfigur (1800-1950) by Georg Strasser. |
EPSG |
POSC |
epicentre 2.1 |
current |
Sphere |
Authalic sphere. 1/f is infinite. |
EPSG name |
|
6371000 m |
6371000 m |
|
EPSG |
POSC |
epicentre 2.1 |
current |
GRS 1967 |
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. |
EPSG name |
298.2471674 |
6378160 m |
|
Geodetic Reference System 1967; International Association of Geodesy special publication number 3; August 1971. |
EPSG |
POSC |
epicentre 3.0 |
current |
Average Terrestrial System 1977 |
|
EPSG name |
298.257 |
6378135 m |
|
New Brunswick Geographic Information Corporation land and water information standards manual |
EPSG |
POSC |
epicentre 2.1 |
current |
Everest (1830 Definition) |
Everest gave a and b to 2 decimal places and also 1/f=300.8017 (to 4 decimal places). |
EPSG name |
300.8017 |
20922931.8 ftInd |
20853374.58 ftInd |
Ellipsoidisch Parameter der Erdfigur (1800-1950) by Georg Strasser |
EPSG |
POSC |
epicentre 3.0 |
current |
WGS 72 |
|
EPSG name |
298.26 |
6378135 m |
|
|
EPSG |
POSC |
epicentre 3.0 |
current |
Everest 1830 (1962 Definition) |
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. |
EPSG name |
300.8017255 |
6377301.243 m |
|
|
EPSG |
POSC |
epicentre 3.0 |
current |
Everest 1830 (1975 Definition) |
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. |
EPSG name |
300.8017255 |
6377299.151 m |
|
|
EPSG |
POSC |
epicentre 2.1 |
current |