由日本財團資助的 "海底2030 "正在鼓勵任何遠離陸地的人打開他們的聲納設備，進行深度探測。而且這不僅僅是大船的測量，裝有數據記錄器的小型遠洋遊艇也可以做出貢獻。
Seabed 2030的明星之一是美國冒險家Victor Vescovo。這位德克薩斯州的金融家正在使用一個潛水器訪問世界上最深的地方，但他所到之處，他的支持船都會打開回聲測深儀。
It's thought a further 10-15% is still squirrelled away on servers, in part because the owners worry they might be giving away commercial or defence secrets if they release the information.
"One of the messages we're trying to get across is that we don't require high-resolution data. Hi-res is nice; we can work with it. But lower resolution is perfectly acceptable.
In addition, the rugged seafloor influences the behaviour of ocean currents and the vertical mixing of water. This is information required to improve the models that forecast future climate change - because it is the oceans that play a pivotal role in moving heat around the planet.
At the moment, our knowledge of just over three-quarters of the planet's underwater terrain comes only from low-resolution satellite measurements that have inferred the presence of tall seamounts and deep valleys from the gravitational influence these features have on the sea surface. Water piles up over the mass of a large submarine mountain and dips slightly where there is a trench.
Seabed 2030, which is funded by Japan's Nippon Foundation, is encouraging anyone who ventures away from the land to switch on their sonar equipment and take depth soundings. And this isn't just about measurements from big ships; small ocean-going yachts fitted with data loggers can also make a contribution.
One of Seabed 2030's stars is the American adventurer Victor Vescovo. The Texan financier is using a submersible to visit the deepest places in the world's oceans, but everywhere he goes his support ship switches on its echosounder.
"We're not a commercial outfit so we don't have to follow the most fuel-efficient routes. When we go on an expedition we ask [Seabed 2030], 'what are your priority areas?'; and we divert a little bit to cover those areas."
It's clear, however, that to come close to obtaining a full picture of the shape of Earth's ocean bottom, there will need to be a step change in approach and capability. Many parts of the world are so remote, few ships will visit them, let alone acquire depth data in those regions.
There is a glimpse of how this will work in one line of data featured in the map at the top of this page. It was gathered by the Saildrone Surveyor on a cruise between San Francisco and Honolulu last year.