Understanding hydrographic data

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

Our hydrographic survey data meets the high-quality standards required to produce and update authoritative nautical chart products for navigation safety. This data can also be used for further analysis to support scientific research into areas such as seabed habitat mapping, anthropogenic impact and monitoring marine aquaculture farms.

Data collected in a hydrographic survey

Bathymetry is one of the key types of data collected in a hydrographic survey. A bathymetric model shows the topography of the seabed and can be used to extract terrain attributes like slope and rugosity. LINZ also collect the strength of the multi-beam sonar return signals (backscatter) which can give information about the bottom type and is a key dataset for habitat mapping. In addition, the water column reflectance is recorded which can be used to extract features above the seabed like algae, wrecks, gas plumes or fish schools.

Additional sensors can be deployed to collect information about currents, water temperature,salinity and density, acidity levels, etc. These factors can influence the biodiversity and species abundance and be of interest for ecologists. It can also be used by councils to refine mooring or anchorage areas, update consents for shoreline infrastructures or help assess coastal erosion for monitoring and planning purposes.

Partnership opportunities

There are opportunities for other organisations to collaborate with us on our hydrographic surveys to collect additional data. Instead of duplicating efforts and expenses to collect marine data, organisations can leverage from our surveys to collect information required for their own projects.

For more detail about the types of information that can be extracted from a hydrographic survey, how it can be used and ways of working with us see: