Heights can be transformed between the 13 major local vertical datums and New Zealand Vertical Datum 2016 (NZVD2016) using relationship grids.

The 13 local vertical datums (LVD) datums are defined in terms of mean sea level at their respective standard ports. They offset from each other and from NZVD2016. The value of this offset varies depending on horizontal position; this means that a relationship grid is required when transforming heights between datums. 

The vertical datum relationship grids can be used in conjunction with NZGeoid2016 to transform NZGD2000 ellipsoidal heights to normal-orthometric heights in terms of the local datums. The relationships between the different height surfaces are shown in the figure below.

Diagram showing the relationship between different height surfaces
Diagram showing the relationship between different height surfaces

The vertical datum relationship grids are calculated using the values from the local datum to NZGeoid2016. These values are interpolated on a 2’ x 2’ arc grid of which covers the datum extent. The vertical datum relationship grid values are positive when NZGeoid2016 is above the local datum.

Local vertical datum

Relationship grid extents

One Tree Point 1964

34.3°S – 36.8°S, 172.6°E – 175.0°E

Auckland 1946

36.1°S – 38.0°S, 174.0°E – 176.2°E

Moturiki 1953

36.5°S – 40.7°S, 174.5°E – 178.3°E

Gisborne 1926

37.4°S – 39.0°S, 177.0°E – 178.6°E

Napier 1962

38.6°S – 40.6°S, 175.6°E – 177.9°E

Taranaki 1970

38.3°S – 41.1°S, 173.6°E – 176.4°E

Wellington 1953

39.1°S - 41.6°S, 174.4°E – 176.4°E

Nelson 1955

40.4°S – 42.7°S, 171.3°E – 174.4°E

Lyttelton 1937

41.3°S – 45.1°S, 168.5°E – 174.2°E

Dunedin 1958

43.9°S – 46.5°S, 168.4°E – 171.3°E

Dunedin-Bluff 1960

45.0°S – 46.7°S, 167.4°E – 169.9°E

Bluff 1955

46.3°S – 46.8°S, 168.2°E – 169.9°E

Stewart Island 1977

46.5°S – 47.5°S, 167.2°E – 168.8°E

There is a unique vertical datum relationship grid for each of the LVD, the location and extents of which are shown in the image below. 

Map showing LVD extents over NZ
Map of New Zealand showing LVD location and extents

 

RegionLocal vertical datumnumber of control marksMean (m)Standard DeviationMin (m)Max (m)Range (m)Reference MarkDatum Relationship at ReferenceRelationship Grid Grid Version
One Tree Point One Tree Point 19641370.0770.042-0.030.1550.185RNZN BM (DJM9)0.080OTP64-NZVD162016.1
Auckland Auckland 19462600.2920.0290.2260.3670.14298-21 SO 69501 (DD1N)0.367AUK46-NZVD162016.1
Moturiki Moturiki 19535190.3090.0710.1400.5400.401BC 84 (B309)0.199MOT53-NZVD162016.1
Gisborne Gisborne 19262740.3430.0250.2530.3970.143GB 01 (ACVP)0.361GSB26-NZVD162016.1
NapierNapier 19622070.2030.0340.1240.2990.175H 40 (B3XM)0.193NPR62-NZVD162016.1
Taranaki Taranaki 19701250.2860.0260.2160.3560.140New Plymouth Fundamental (AGMH)0.297TNK70-NZVD162016.1
Wellington Wellington 19531370.4080.0540.2960.5170.221K 80/1 (ABPB)0.388WGN53-NZVD162016.1
Nelson Nelson 19552560.3290.0390.2150.4400.225N 1 (AC4T)0.330NSN55-NZVD162016.1
Lyttelton Lyttelton 19379230.3400.0410.2000.4890.289UD 40 (B40V)0.389LTN37-NZVD162016.1
Dunedin Dunedin 19581970.3260.0430.1740.4580.284WW 83 (AFEQ)0.377DUN58-NZVD162016.1
Dunedin-Bluff Dunedin-Bluff 19602050.2540.0390.1540.3640.210Z 41 (B3R8)0.329DBL60-NZVD162016.1
Bluff Bluff 1955710.2730.0340.2130.3520.138Bluff Fundamental (ABCC)0.316BLF55-NZVD162016.1
Stewart Island Stewart Island 197740.2990.0250.2760.3380.062N (Paterson SD) (A017)0.299STI77-NZVD162016.1
Last Updated: 24 June 2016