New Zealand bathymetry - Further information

Technical information about our datasets and methodology along with related resources.

Source information - NZ region bathymetry

Bathymetric compilation, interpretation, and terrain model by Charting Around New Zealand (CANZ) group.

Bathymetry compiled from data held at the National Institute of Water & Atmospheric Research (NIWA); Hydrographic Office, Royal New Zealand Navy; National Geophysical Data Centre (U.S.); South Pacific Applied Geoscience Commission (Fiji); published scientific papers; recent swath bathymetric surveys funded by NIWA, Institute Francais de Recherche pour l’Exploitation de la Mer (IFREMER), France; Seabed Mapping New Zealand Limited and Land Information New Zealand (LINZ).

Onshore data are derived from Eagle Technology Ltd.’s EagledataTM, which is a derivative of the 1:50 000 Digital Vector Topographic Land Information New Zealand dataset.

Ships’ tracks

5,005,568 km of single beam ship tracks providing depth information. Data confidence is greater in areas of dense coverage (black) versus areas of sparse to no coverage (white). See Figure 1. to the right.

Multibeam swath locality diagram

Areas (2,593,115 km2, including overlaps) where multibeam swath depth information of the seafloor around New Zealand have been acquired. The resulting surveys show far greater detail than multiple lines using a single beam echo sounder. See Figure 2.

Bathymetric Tints

These are the colour coded depths on our bathymetry charts. See Figure 3. and 4.

How do we map the sea floor?

The sea floor is mapped using various types of echo sounders. Single beam echo sounders, which direct a single beam of sound to the seabed directly below a ship, only provide depth information along the ship's trackline. Tracklines are often spaced 10's to 100's of kilometres apart, thus features lying between are not visible to the system. Alternatively multibeam echo sounders emit a fan of sound beams to the seafloor to scan a wide swath of the seabed in great detail and thus mapping all features on the seabed.  

Multibeam echo sounder system

Hull-mounted on the RV Tangaroa, the EM-302 multibeam echosounder maps the seafloor using a fan of 288 acoustic beams, producing up to 864 soundings per ping in dual swath mode, providing 100% coverage of the seabed. Only recently have oceanographers been able to map the seabed in something near the detail possible on land. Using acoustic technology we can now produce accurate, aerial-like images of the seafloor. See Figure 5.

Discovering the ocean floor

In 1874, HMS Challenger conducted the first oceanographic survey of the world ocean. This was the start of systematic charting of the southwest Pacific Ocean. Since then, successive surveys by naval and oceanographic ships have greatly improved our knowledge of the 4 million square kilometres of ocean enclosed by the New Zealand Exclusive Economic Zone. See Figure 6.

Go to our charts and posters to view and purchase printed copies.

Map information and metadata

Projection Mercator (WGS84 Datum) at 41°S.

This chart includes all of British Admiralty areas 383, 384, 385, 414, 415, 416, 445, 446, 447, 474, 475, 476, 501 and parts of 382, 386, 500, 524, 525, 526.

Digital data information 

Projection Mercator (WGS84 Datum) at 41°S true latitude and 100°E central meridian (EPSG 3994).

Bibliographic reference

CANZ, 2008: New Zealand Region Bathymetry, 1:4 000 000, 2nd Edition. NIWA Chart, Miscellaneous Series No. 85.

Attribution: Content, Datasets and Imagery provided by NIWA

Source information - Hauraki Gulf bathymetry

Onshore land representation derived from Land Information New Zealand topographic and the Ministry for the Environment LCDB II digital datasets.

Offshore representation derived from Land Information New Zealand hydrographic and NIWA bathymetric surveys.

Not to be used for navigational purposes. 

Hauraki Gulf data coverage

Denotes areas where multibeam swath and single beam information of the Hauraki seafloor  have been acquired.  Data confidence is greater in areas of dense coverage (gray) versus areas of sparse coverage (white).  See Figure 7.

Map information and metadata

Projection Mercator (WGS84 Datum) at 41°S.

Digital data information

Projection Mercator (WGS84 Datum) at 41°S true latitude and 100°E central meridian (EPSG 3994). 

Bibliographic reference

Mackay, K.A., Mackay, E.J., Neil, H.L., Mitchell, J.S., Bardsley, S.A., 2012: Hauraki Gulf. NIWA Chart, Miscellaneous Series 91

Published by the National Institute of Water & Atmospheric Research Ltd

Copyright © All rights reserved

Attribution: Content, Datasets and Imagery compiled by NIWA, from data sourced from NIWA and LINZ.

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Figure 1. Ships’ tracks. 5,005,568 km of single beam ship tracks providing depth information.

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Figure 2. Multibeam swath locality diagram. Areas (2,593,115 km2, including overlaps) where multibeam swath depth information of the seafloor around New Zealand have been acquired. [NIWA]

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Figure 3. Bathymetric tints. These are the colour coded depths on our bathymetry charts.

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Figure 4. RV Tangaroa's sophisticated multibeam echosounder can trace the image of a seabed 7.5 kilometres beneath the surface. [Erica Mackay]

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Figure 5. Multibeam bathymetric image of an active submarine volcano from the Kermadec Ridge.

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Figure 6. Discovering the Ocean Floor poster.

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Figure 7. Hauraki Gulf data coverage. Denotes areas where multibeam swath and single beam information of the Hauraki seafloor have been acquired. Data confidence is greater in areas of dense coverage (gray) versus areas of sparse coverage (white). [NIWA]