The Orders of normal-orthometric heights have been updated to reflect the accuracy definitions in the LINZS25005 and LINZS25006 standards.

LINZS25005
LINZS25006

The major change to the height Orders is that they now provide information about the accuracy of the height, whereas the previous height Orders were based on the method of survey.

LINZ does not describe the accuracy of ellipsoidal heights using these Orders. Instead the vertical accuracy of the control mark Orders is used for ellipsoidal heights because they are determined in conjunction with the horizontal position.

The height Orders and the changes from the previous system are summarised in the following table:

OrderPurposeNetwork AccuracyLocal Accuracy
Tier(m)ClassConstant
(m)
Proportion
(m/m)
Relative Accuracy (old)
1VNational Height NetworkE0.30VI0.013x10-61st and 2nd order precise levelling
2V-F0.35VII0.011x10-53rd order precise levelling
3VCadastral Vertical ControlF0.35IX0.021x10-4Less accurate techniques with 1V or 2V origin
4V-G0.50X0.021.5X10-4Systemic techniques with poor origin or correction
5V-H1XII0.306x10-4Unknown or unreliable accuracy
6V-------

Previous values are shown in italics. The terms 1st and 2nd Order precise levelling refer to the misclose of the levelling observations.