This zip file contains the following files:

nzgeoid05.lln.zip :

Lists the 2 arc-minute grid of geoid values as
(longitude latitide geoid) triplets for each grid cell within the
area of computation (160°E-170°W, 25°S-60°S).


nzoffset05.txt :

Lists the offset from NZGeoid05 to each of the thirteen major
New Zealand levelling datums.


readme.txt :

The file you are currently reading.



To convert from ellipsoid heights to levelling heights subtract the
geoid and add the offset to the ellipsoid height.

For example: CE 21 (Geodetic Code: ADND), Auckland 1946

Latitude:           36° 58' 25.78152" S
Longitude:          174° 59' 31.29868" E
NZGD2000 height:    120.660 m

To convert to Auckland 1946 levelling datum:

Interpolated geoid: 34.5516 m
Auckland offset:    0.496 m

Auckland height = NZGD2000 - geoid + offset
                = 120.660 - 34.5516 + 0.496
                = 86.6044 m


