The North Island and South Island of New Zealand have been mapped on one projection with one grid known as the New Zealand Map Grid.

The projection adopted was derived from mathematical analysis to give a small range of scale variation over the land area of New Zealand. This has been achieved at the expense of abandoning the orderly arrangement of scale curves. Such a projection has no recognized name. It is simply called the New Zealand Map Grid projection. The projection is conformal but is unlike any other projection used for detailed mapping.

Easting values are always less than 5,000,000 meters and northing values are always greater than 5,000,000 meters.

There are no required parameters for defining a New Zealand Map Grid Coordinate System in the Geographic Calculator.