This index enables you to identify the freely available georeferenced TIFF images of sounding sheets held by LINZ for the New Zealand coastal area. Some of these sounding sheets date back to the 1930s. The polygons comprising the index show the extent of each original hard copy sheet - not just the soundings shown on the sheet. The attributes attached to each polygon will enable you to view, amongst other attributes, the date and scale of the bathymetric data shown on the sounding sheet.
Please refer to the LINZ Bathymetric Index Data Dictionary for further information about the attributes of this dataset. The georeferenced TIFF images are not downloadable from the LINZ Data Service.
Requests for sounding sheets should be sent to firstname.lastname@example.org 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 sounding sheets of interest.
LINZ also holds images of New Zealand sounding sheets provided by third parties, which are subject to different licencing terms and conditions. View our "NZ Scanned Sounding Sheet Index – Third Party" dataset to request these sounding sheets.
The Royal New Zealand Navy and, more recently, LINZ have been responsible for undertaking or commissioning hydrographic surveys to faciliate the prodcution of nautical charts to enable New Zealand to meet its obligations under the International Convention for the Safety of Life at Sea.
Traditionally the bathymetric data collected during hydrogarphic surveys was rendered only as sounding sheets in hard copy form, often as A1 (or larger) sheets. More recently the bathymetric datasets have often been rendered as both sounding sheets and as digital data files, with the provision of sounding sheets diminishing over time. The sounding sheets have been scanned and georeferenced to make them available as TIFF images.
The index has been derived from the extents of the georeferenced images and infomration held in LINZ's hydrographic information database.
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.