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This section will provide a generalised overview of the Geocentric
Datum of Australia. For more information refer to the GDA homepage and also look at our
next page (Datum Overview).
"News in Science - Australia prepares to shift north - Friday, 13
November 1998
Sometime during the year 2000, the Australian landmass will
shift 200 metres to the northeast.
The move will occur when Australia officially adopts a new map reference system, the
Geocentric Datum of Australia (GDA), to bring it in line with international satellite
navigation technology. The GDA is calculated mathematically, using the earth's centre of
mass as a reference point, rather than the current standard, the Australian Geodetic
Datum, which is based on astronomic positions.
The two reference systems vary by about 200 metres - a constant source of confusion for
bushwalkers, four-wheel drivers and boating enthusiasts whose maps don't line up with
their satellite global positioning coordinates.
State governments are currently phasing in the new reference system and all Australian
government bodies will convert to the GDA by the year 2000. The changes will particularly
affect the mining industry since most mining leases are defined by map coordinates.
The latitude and longitude of most Australian landmarks will change under the GDA by
between 190 and 210 metres."
Sourced from The Lab (www.abc.net.au/science)
© 1998 Australian Broadcasting Corporation
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