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Find the period over which tidal observations were analysed to produce our tide predictions.

How to calculate the times and heights of and between high and low waters.

Unusually high or low barometric pressure, or prolonged periods of strong winds, can mean the actual sea level is higher or lower than the predicted height.

Until quite recently the use of float gauges was the most common method of measuring and recording sea levels.

New Zealand and Australia have rights over areas of ocean called their Exclusive Economic Zones (EEZ).

Download New Zealand’s maritime boundaries

Standards and specifications for carrying out hydrographic surveys for safety of navigation, and the benefits of hydrographic survey data.

Tidal levels for standard ports, information on reading tide predictions, and the standard port datum descriptions for New Zealand ports.

Find out about tide prediction formats and how to interpret the values.

Find New Zealand's standard port chart datums. These are the datums used for stating the depths of the sea on nautical charts, including the level of the water at ports.

New Zealand's tidal regime is semi-diurnal, so on most days two high and two low tides occur at any location.

Learn about tidal theory and the different types of tides around New Zealand.

Information on applications to undertake marine scientific research (MSR).

Data about the marine environment which helps us understand how to protect our biodiversity and ecosystems.

Finding and accessing data facilitates its reuse.

Find out about what causes tides and how they vary depending on time and location.

LINZ publishes Annual New Zealand Notices to Mariners and fortnightly New Zealand Notices to Mariners (NTMs).

Learn about keeping your nautical charts up-to-date with our Notices to Mariners.

Toitū Te Whenua LINZ collects hydrographic data for charting purposes using our hydrographic standards and technical specifications detailed in HYSPEC.

A “collect once, use many times” approach can grow the value of marine geospatial data.

Find out more about New Zealand's maritime zones and boundaries.

Find the standard tidal levels for ports around New Zealand.

Definitions of common tidal terms.

The tide you see is a combination of all the different water movements happening at that location.

Standards and specifications for hydrographic surveys and the production of nautical charts and publications, and links to International Hydrographic Organization (IHO) resources.

You can keep your charts and nautical publications up to date using our Notices to Mariners.

Information for survey and spatial professionals who are preparing maps to support applications by iwi, hapu or whānau groups for recognition of customary interests under the Marine and Coastal Area (Takutai Moana) Act 2011.

New Zealand has sovereign rights over a vast area of ocean, along with the fishery, mineral and petroleum resources that may exist in that area.

How to print tracings and blocks in Notices to Mariners.