The accuracy of a coordinate or height can be measured in different ways. Toitū Te Whenua uses orders to determine coordinates which meet both a network and local accuracy standard:
- Network accuracy represents the absolute uncertainty of a coordinate in relation to a datum. Network accuracy is categorised by tier.
- Local accuracy represents the uncertainty of a coordinate in relation to other nearby coordinates. Local accuracy is categorised by class.
In general, the lower the order number the more accurate the coordinate is, with 0 the most accurate and 12 the least accurate. Three order classifications are used in New Zealand:
The current order framework has been in place since 2010.
Read more about past coordinate and height orders
New Zealand Geodetic Datum 2000 (NZGD2000), Ross Sea Region Geodetic Datum 2000 (RSRGD2000) and New Zealand Vertical Datum 2016 (NZVD2016) order have been determined using statistical testing, in the National Geodetic Adjustment.
The National Geodetic Adjustment
Historic coordinates (such a New Zealand Geodetic Datum 1949 (NZGD1949) and local vertical datum were determined based on observational accuracy.