GEOGRAPHY:

FOR experts in the field of ocean mapping, it is no small irony that we know more about the surfaces of the moon and Mars than we do about our planet’s sea floor.

‘‘Can you imagine operating on the land without a map, or doing anything without a map?’’ asked Larry Mayer, director of the USbased Centre for Coastal and Ocean Mapping, a research body that trains hydrographers and develops tools for mapping.

‘‘We depend on having that knowledge of what’s around us — and the same is true for the ocean.’’

With their deep craters and mountain ranges, the contours of the earth beneath the waves are both vast and largely unknown.

But a huge mapping effort is under way to change that. The UNbacked project, called Seabed 2030, is urging countries and companies to pool data to create a map of the entire ocean floor by 2030. The map will be freely available to all.

‘‘We obviously need a lot of cooperation from different parties — individuals as well as private companies,’’ said Mao Hasebe, project coordinator at the Nippon Foundation, a Japanese philanthropic organisation supporting the initiative.

‘‘We think it’s ambitious, but we don’t think it’s impossible.’’

The project, which launched in 2017, is expected to cost about $US3 billion ($NZ4.37 billion). It is a collaboration between the Nippon Foundation and Gebco, a nonprofit association that is already involved in charting the ocean floor.

The end result would be greater knowledge of the oceans’ biodiversity, improved understanding of the climate, advanced warning of impending disasters and the ability to better protect or exploit deepsea resources, Hasebe said.