Navigating elevation data in Auckland requires knowing which vertical reference system your plans use, especially as local projects fully adopt modern height standards. Auckland Level Datum 1946 (AUCK1946) and New Zealand Vertical Datum 2016 (NZVD2016) are the two primary systems you will encounter across site plans, drainage as-builts, and council records.
Understanding the Two Datums
| Feature | AUCK1946 (Auckland Level Datum 1946) | NZVD2016 (NZ Vertical Datum 2016) |
| Basis | Local Mean Sea Level recorded at Auckland Harbour tide gauges in 1946 | Modern nationwide gravity model (NZGeoid2016) and satellite positioning |
| Coverage | Auckland regional area only | Unified nationwide standard |
| Status | Historical regional standard; legacy system | Official nationwide height datum adopted by Auckland Council on 1 July 2024 |
| Key Advantage | Simple historical benchmark network | Highly accurate, seamlessly links with GPS/GNSS, immune to sea-level shifts |
The Elevation Offset
Across the Auckland region, NZVD2016 heights are lower than AUCK1946 heights by approximately 250 mm to 360 mm. Because early physical levelling accumulated minor distortions across long distances, the shift is not a single flat number—it varies based on your precise location.
To convert between the two systems, apply the site-specific offset:
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Converting to NZVD2016: NZVD2016 = AUCK1946 – Offset
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Converting to AUCK1946: AUCK1946 = NZVD2016 + Offset
Example: A benchmark recorded at 10.000 m in AUCK1946 with a local offset of 0.288 m becomes 9.712 m in NZVD2016.
Methods for Converting Site Heights
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LINZ Data Service (GIS & CAD): Use Toitū Te Whenua LINZ’s online transformation software or upload the official grid file (
AUCK46-NZVD2016) into your spatial tools for automatic coordinate-based conversion. -
Dual-Datum Benchmarks: For small localized sites, reference nearby survey marks that publish official elevations in both datums to derive your local offset.
Surveyor’s Warning: Always check the title block on site plans, flood hazard maps, and drainage diagrams. A 300 mm datum mix-up can cause gravity-fed stormwater pipes to slope backward or result in non-compliant finished floor levels (FFL) relative to flood plains.