Geodetic Datums

This section describes the geodetic datums that are currently or that have previously been used in New Zealand and information about their reference ellipsoids.

A geodetic datum is a reference system for describing positions on the curved surface of the Earth. Datum coordinates are normally expressed in degrees, minutes and seconds of latitude and longitude.

New Zealand Geodetic Datum 2000 (NZGD2000)

This is the current official geodetic datum for New Zealand and its offshore islands that was implemented in 1998. more...

Ross Sea Region Geodetic Datum 2000 (RSRGD2000)

This is the current official geodetic datum for the Ross Sea region of Antarctica that was implemented in 2000. more...

World Geodetic System 1984 (WGS84)

This is the datum used by the Global Positioning System (GPS). New Zealand's current official datums (NZGD2000 and RSRGD2000) are coincident with WGS84. more...

New Zealand Geodetic Datum 1949 (NZGD1949)

Implemented in 1949, this datum served New Zealand's needs well for over 50 years. A number of deficiencies in its definition led to its replacement with NZGD2000 in 1998. more...

Chatham Islands Geodetic Datum 1979 (CIGD1979)

This was the official geodetic datum for the Chatham Islands until it was superseded in 1998 by the NZGD2000. more...

Chatham Islands Geodetic Datum 1971 (CIGD1971)

This was the official geodetic datum for the Chatham Islands until it was superseded in 1981 by the CIGD1979. more...

Reference ellipsoids

The above geodetic datums are based on ellipsoidal approximations of the earth's shape. This section describes the two ellipsoids used in New Zealand: Geodetic Reference System 1980 (GRS80), International 1924 and World Geodetic System 1984 (WGS84). more...