This index enables you to identify the freely available bathymetric data held and used by LINZ on its Antarctic (Ross Dependency) coastal nautical charts. Some of our data holdings date back to the 1960s. The polygons comprising the index show the extent of the survey datasets. The attributes attached to each polygon will enable you to view, amongst other attributes, the age and quality of the bathymetric data.
Please refer to the LINZ Bathymetric Index Data Dictionary for further information about the attributes of this dataset.
The bathymetric data is not downloadable from the LINZ Data Service. Datasets prior to the year 2000 are predominantly available only as georeferenced TIFF images of the original hard copy sounding sheets. Data post-2000 is often available as both georeferenced TIFF images and as digital data files (vector data in plain text format).
Requests for the bathymetric data should be sent to email@example.com with “Hydro Bathy Data” in the subject line. Requests must, as a minimum, specify the id, chart_no and serial_no as shown in the attributes attached to each polygon representing the datasets of interest.
The Royal New Zealand Navy and, more recently, LINZ have been responsible for undertaking or commissioning hydrographic surveys to facilitate the production of nautical charts to enable New Zealand to meet its obligations under the International Convention for the Safety of Life at Sea.
Prior to the year 2000 the bathymetric data collected during hydrographic surveys was rendered only as sounding sheets in hard copy form, often as A1 (or larger) sheets. Post-2000 the bathymetric datasets have often been rendered as both sounding sheets and as digital data files. The sounding sheets have been scanned and georeferenced to make them available as TIFF images.
This index has been derived from extents and information derived from the bathymetric datasets used on Antarctic (Ross Dependency) coastal nautical charts as at October 2014. Some data on our Antarctic nautical charts dates back to 1965, however, for all data since that date you will also need to refer to the Antarctic Scanned Sounding Sheet index.
With the exception of dense point cloud datasets, LINZ’s bathymetric data is usually based on minimum seabed depth (shoal-biased) values. This means if two soundings are close together we choose the lesser (shallower) one as safety is our primary concern.