Abstract
The implementation of the Geocentric Datum of Australia (GDA) is proceeding, with its nationwide implementation recommended by the year 2000. This involves an approximate 200-metre change from existing Australian Geodetic Datum (AGD) coordinates. The definitions of regional and geocentric datums, and the history of datums in Australia are reviewed. The benefits and effects of the GDA upon the users and producers of spatial information are coined. The method of updating maps and spatial databases, using a seven-parameter transformation, is explained.