Eight months, 30 terabytes and 40,000 hectares later, a state-of-the-art scanning project of the Marlborough Sounds seabed has wrapped up.
The scans of Queen Charlotte Sound and Tory Channel will create three-dimensional maps of the depths below, and mark the first significant update to boat charts since 1942.
The joint project between Marlborough District Council, National Institute of Water and Atmospheric Research (NIWA) and Land Information New Zealand (LINZ) began in October last year.
Niwa national projects manager Dr Helen Neil said the Sounds had thrown up some challenges for the hydrographic and scientific survey.
"Successful work was carried out in a challenging marine environment, the palette of the Sounds changed each day with sunshine, fog and occasionally those windy bumpy seas," she said.
"It has been a privilege to work within one of New Zealand's natural treasures, unlocking nature's secrets and working with a community that is passionate about the environment."
Multi-beam technology was used to map the seabed and capture water column features.
Scientists described the process as similar to "mowing the lawn" - where they proceeded up and back to scan each strip of the ocean floor.
The results would offer a data-rich snapshot of the sea floor to determine habitats, identify seeps and plumes and detect fish shoals and kelp beds.
The team from Niwa spent about 2800 hours on the water to finish the job, Neil said.