New Zealand offshore island projections

Toitū Te Whenua has responsibilities for mapping and supporting the use of spatial data for New Zealand and its surrounding offshore islands. Different mapping projections will best represent the data of different areas, so individual projections have been created for each of the offshore island groups.

There will always be some distortion when coordinates are converted from a curved surface, such as Earth, to a flat map. Projections help to manage this distortion so the resulting map best supports the needs of its users. The projection used on the New Zealand mainland, New Zealand Transverse Mercator 2000 (NZTM2000), has distortion in its east-west extents. As a result it is not recommended for mapping offshore islands, and separate projections are used for New Zealand's continental shelf:

New Zealand Continental Shelf Lambert Conformal 2000 (NZCS2000)

The projections for our offshore island have been developed using a transverse Mercator projection. This is cylinder-shaped and is well suited for depicting elongated areas, like New Zealand. The false Northing and Easting coordinates of the different projections ensure that different points on land will not have the same coordinates, reducing the chance of confusion.

The offshore island projections are defined in the LINZ standard LINZS25002:

Standard for New Zealand Geodetic Datum 2000 Projections