Abbreviation

Ellipsoid Name

Length of Major Axis (a)

Reciprocal of Flattening (1/f)

airy

Airy 1830

6377563.396000m

299.32497530

andrae

Andrae 1876

6377104.430000m

300.00000000

aust_SA

Australian National & South American 1969

6378160.000000m

298.25000000

APL4.9

Applied Physics Laboratory 1965

6378137.000000m

298.25000000

ATS77

Average Terrestrial System 1977*

6378135.000000m

298.25700000

bessel

Bessel 1841

6377397.155000m

299.15281285

bess_mod

Bessel 1841 (Modified)

6377492.017600m

299.15281000

bess_nam

Bessel 1841 (Namibia)

6377483.865000m

299.15281285

clrk58

Clarke 1858

6378293.639000m

294.26068000

clrk66

Clarke 1866

6378206.400000m

294.97869820

clrk66mi

Clarke 1866 (Michigan)

6378693.704000m

294.97868450

clrk80

Clarke 1880 Modified (Arc)

6378249.145326m

293.46630760

clrk80ben

Clarke 1880 Modified (Benoit)

6378300.790000m

293.46623450

clrk80IGN

Clarke 1880 Modified (IGN)

6378249.200000m

293.46602130

clrk80o

Clarke 1880

6378249.136000m

293.46631540

clrk80RGS

Clarke 1880 Modified (RGS)

6378249.145000m

293.46500000

clrk80SGA

Clarke 1880 Modified (SGA 1922)

6378249.200000m

293.46598000

CPM

Commission des Poids et Mésures 1799

6375738.700000m

334.29000000

danish

Danish National Grid*

6377103.965000m

300.00000000

delmbr

Delambre 1810

6376428.000000m

311.50000000

engelis

Engelis 1985

6378136.050000m

298.25660000

evrst30

Everest 1830

6377276.345800m

300.80170000

evrst48

Everest 1948

6377304.063000m

300.80170000

evrst56

Everest 1956

6377301.243000m

300.80174000

evrst69

Everest 1969

6377295.664000m

300.80170000

evrstP

Everest (Pakistan)*

6377309.613000m

300.80170000

evrstSS

Everest (Sabah & Sarawak)

6377298.556000m

300.80170000

fschr60

Fischer (Mercury Datum) 1960

6378166.000000m

298.30000000

fschr60m

Modified Fischer 1960

6378155.000000m

298.30000000

fschr68

Fischer 1968

6378150.000000m

298.30000000

fschr68mmd

Fischer 1968 (MMD)*

6378160.000000m

298.24716740

GRS67

Geodetic Reference System 1967 or International Astronomical Union 1968

6378160.000000m

298.24716743

GRS80

Geodetic Reference System 1980 or New International

6378137.000000m

298.25722210

helmert

Helmert 1906

6378200.000000m

298.30000000

hough

Hough 1960

6378270.000000m

297.00000000

IAU76

International Astronomical Union 1976

6378140.000000m

298.25722200

indon

Indonesian National Spheroid

6378160.000000m

298.24700000

intl

International or Hayford

6378388.000000m

297.00000000

kaula

Kaula 1961

6378163.000000m

298.24000000

krass

Krassovsky 1942 (1940)

6378245.000000m

298.30000000

lerch

Lerch et al. 1979

6378139.000000m

298.25700000

MERIT

MERIT 1983

6378137.000000m

298.25700000

mod_airy

Modified Airy 1849

6377340.189000m

299.32493740

mprts

Maupertius 1738

6397300.000000m

191.00000000

new_intl

New International 1967

6378157.500000m

298.24961540

NWL9D

Naval Weapons Laboratory 1965

6378145.000000m

298.25000000

OSU86F

OSU86 Gravity Potential Model

6378136.200000m

298.25722000

OSU91A

OSU91 Gravity Potential Model

6378136.300000m

298.25722000

plessis

Plessis 1817

6376523.000000m

308.64099710

seasia

Southeast Asia

6378155.000000m

298.30000720

SGS85

Soviet Geodetic System 1985

6378136.000000m

298.25700000

shdanov

Shdanov 1893

6377717.000000m

299.70000000

struve

Struve 1860

6378297.000000m

294.73000000

walbeck

Walbeck 1817

6376896.000000m

302.78000450

war_off

War Office

6378300.583000m

296.00000000

WGS60

World Geodetic System 1960

6378165.000000m

298.30000000

WGS66

World Geodetic System 1966

6378145.000000m

298.25000000

WGS72

World Geodetic System 1972

6378135.000000m

298.26000000

WGS84

World Geodetic System 1984

6378137.000000m

298.25722356