This topic describes the nature and applicability of the geodetic transformation techniques supported by the coordinate conversion system. The USE clause present in each datum definition identifies the technique that will be applied to transform coordinates between datums.
With few exceptions, the geodetic transformation is a mathematical process by which geographic coordinates are converted from some datum to the WGS84 reference ellipsoid.
Available geodetic transformation methods:
NZGD49 to NZGD2K via Grid File
Seven Parameter Transformation
Three Parameter Transformation
WGS72 to WGS84 via DMA Formula