Height Conversions

The two height systems used in New Zealand are normal-orthometric and ellipsoidal. Normal-orthometric heights refer to the Earth’s gravity field and include the NZVD2009 and 13 local mean sea level datums. Ellipsoidal heights refer to a geometric figure approximating the Earth (an ellipsoid) and include the NZGD2000 and GNSS/GPS receivers.

Heights can be converted between datums using NZGeoid2009 as a transformation surface (and also an offset if required). The general relationship between the different datums is shown in the figure below.

This diagram shows the general relationship between the different datums.

Converting between NZVD2009, NZGD2000 and local mean sea level datums

Explains how to convert heights to and from NZVD2009. This conversion uses the NZGeoid2009 geoid model. more...

Converting between local mean sea level datums

Explains how to convert heights between the 13 local mean sea level datums. more...

Examples of height conversion

Examples of the transformation of heights between different datums. more...