You are here: Home > Earth Monitoring > Geodesy & GPS > Geodetic Infrastructure - Datums

Get Acrobat Reader Icon. Use this link to go to Adobe's website and download the Free Acrobat Reader for PDFs. Some of the documents on this webpage may be in PDF Format. Please download the Free PDF reader from Adobe to view these files.
Updated:  24 November 2011

Parameters for commonly used Ellipsoids

Ellipsoid Parameters Ellipsoid Name "165" ANS CLARKE 1858 GRS80 WGS84 WGS72 International 1924
Major Semi Axis a 6378165.000 6378160.000 6378293.645 6378137 6378137 6378135 6378388
Inverse Flattening 1/f 298.3 298.25 294.26 298.2572221 298.2572236 298.26 297
Flattening f = 1 / f 0.003352330 0.003352892 0.003398355 0.003352811 0.003352811 0.003352779 0.003367003
Minor Semi Axis b = a * ( 1 - f ) 6356783.287 6356774.719 6356617.938 6356752.314 6356752.314 6356750.520 6356911.946
Eccentricity e 0.081813334017 0.081820179996 0.082372092204 0.081819191043 0.081819190843 0.081818810663 0.081991889979
Eccentricity squared e**2=2f-f**2=(a**2-b**2)/a**2 0.006693421623 0.006694541855 0.006785161574 0.006694380023 0.006694379990 0.006694317778 0.006722670022
Second Eccentricity e' 0.082088521821 0.082095437120 0.082652976376 0.082094438152 0.082094437950 0.082094053920 0.082268889607
Second Eccentricity squared e'**2=e**2/(1-e**2)=(a**2-b**2)/b**2 0.006738525415 0.006739660796 0.006831514504 0.006739496775 0.006739496742 0.006739433689 0.006768170197

[back to top]

For more information contact: geodesy@ga.gov.au
Unless otherwise noted, all Geoscience Australia material on this website is licensed under the Creative Commons Attribution 3.0 Australia Licence.
feedback | security & privacy | disclaimer | © Commonwealth of Australia 2010 | Creative Commons Attribution Licence