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Mapping the Seabed through Crowdsourced Bathymetry

Mapping the Seabed through Crowdsourced Bathymetry

Disabled fishing boat Sea Siren as the Coast Guard Cutter Juniper prepares to take it in tow. (Photo courtesy of Coast Guard, Petty Officer Officer 3rd Class Jeff Quinn)
Disabled fishing boat Sea Siren as the Coast Guard Cutter Juniper prepares to take it in tow. (Photo courtesy of Coast Guard, Petty Officer Officer 3rd Class Jeff Quinn)

Navigating a vessel or building infrastructure to cross a river may seem like relatively straightforward tasks, but doing so requires intricate knowledge of water’s depth and the terrain beneath it. While most high-traffic waterways have been mapped through systematic hydrographic surveys, approximately 75% of the world’s oceans remains unexplored with modern survey standards. In fact, numerous authors comment that we know more about the surface of Mars and our moon than we do Earth’s own seafloor. 

Lofty goals

With so little known about the seafloor, several organizations — including NGA — aim to work together developing environmentally sustainable and collaborative ocean mapping models. 

Seabed 2030 is the international initiative by the Nippon Foundation — a social innovation hub — and the General Bathymetric Chart of the Oceans — a nonprofit organization dedicated to becoming the leading authority on bathymetric data — to work with partners across industry, governments, research, philanthropy and civil society to achieve a complete map of the ocean floor by 2030. A similar initiative by the United Nations’ Decade of Ocean Science for Sustainable Development works towards creating a digital model of the oceans — a digital twin — within the 2030 timeline.

Achieving these goals would enhance safety of navigation at sea across the globe.

Finding the solution

To satisfy scientific curiosity and bolster safety of navigation, the International Hydrographic Organization and its partners — including NGA — have turned to Crowdsourced Bathymetry (CSB).

Bathymetry — the study of water depths in oceans, lakes and seas — provides a general configuration of the seafloor. The IHO defines CSB as “the collection and sharing of depth measurements from vessels, using standard navigation instruments, while engaged in routine maritime operations.” 

Most oceangoing ships navigate with echo sounding equipment that constantly monitors waters’ depth in accordance with regulations of the International Convention for Safety of Life at Sea. This depth information — if made easily accessible — can be compiled to create a rough map of the ocean’s seafloor without expending additional resources to obtain that data through other means. 

CSB is a collaboration of diverse international stakeholders voluntarily providing bathymetric data obtained incidentally through their routine maritime operations, in line with best maritime practices. CSB differs from systemic hydrographic surveying or marine scientific research since the data has been collected by vessels using standard navigational instruments in their routine operations. In general, CSB is not as precise as data obtained through surveying. 

The benefit of CSB is that, unlike hydrographic surveying or scientific research under the United Nations Convention on the Law of the Sea, it does not require the permission of the coastal state under certain circumstances. The data results from echo sounding records vessels obtain incidentally through routine operations such as vessel passages or transits. The data CSB produces may be the best available in some regions — especially where nothing else currently exists — and can improve navigation information and knowledge of the ocean environment.

Establishing a baseline of bathymetric data through CSB allows for supplemental changes to existing models as new information is gathered.

The role NGA plays

NGA — along with the Naval Oceanographic Office — represents the Department of Defense as part of the U.S. delegation to the IHO. The National Oceanic and Atmospheric Administration represents U.S. civil interests. The U.S delegation aims to promote safety of navigation, and establish and improve development of uniform international standards for hydrographic data, information, products, services and techniques.

Within the IHO, the CSB Working Group strives to provide guidance and advocate for developing technology to collect and distribute CSB data to the public. The amalgamation of the information collected by ships ensures that critical insights into hydrography benefit navigators around the globe. 

Mr. Akim Mahmud, NGA’s Strategic Engagement Representative to IHO’s CSB Working Group, emphasizes the importance of seeking new innovative solutions, technology and collaboration in the maritime community — especially within the CSB initiative.

“Ocean mapping isn’t relatively easy or cheap compared to the vastness of the ocean and ever-changing marine environment,” said Mahmud. “No one single solution or technology will help our ocean become fully mapped in a relatively short time frame.  We need to go grassroots with ocean mapping and encourage a diverse range of maritime stakeholders to get involved with the CSB concept to collect and demonstrate the value of CSB data to a broader international community. “

While CSB aims to provide vital knowledge in maximizing safety of navigation, not every IHO member state is onboard the CSB initiative yet. Of the 99 total member states, only the U.S., Papua New Guinea and the Republic of Palau have approved the unconditional release of CSB in their waters subject to national jurisdiction. Of the remaining states, six have authorized the release of their CSB with minimal caveats, 25 have authorized release with varying caveats and 64 have not responded to the IHO circular letters requesting responses.

“If the IHO continues to generate positive responses from other coastal states, it may lead to the availability of billions of datapoints per year and this can significantly accelerate the goals for Seabed 2030 and building a digital model of the seabed,” said Mr. Steven Keating, an Assistant General Counsel in the Mission and International Law Division of NGA’s Office of General Counsel, and U.S. Observer to the Advisory Board on the Law of the Sea.

Among coastal member states, the U.S. leads the way in authorizing the free distribution of data obtained from vessels within U.S. internal waters, its territorial sea — out to 12 nautical miles — and exclusive economic zone — which generally extends out to 200 nautical miles. 

In line with the example set forth by the U.S., NGA strongly advocates for the free and public availability of CSB to all users. The U.S. provides financial support to the IHO-initiated project to maintain a global database for CSB, hosted by the IHO’s Data Centre for Digital Bathymetry. The database establishes the infrastructure necessary to provide archiving, discovery, display and retrieval of releasable global CSB data for mariners around the world. 

“The collection and release of CSB data in the waters in which NGA acts as a Primary Charting Authority has potential value to NGA for working to maintain accurate and up-to-date nautical charts and maps of their waters,” said Mahmud. “It also provides NGA’s Maritime Safety Office with a free, continuous source of reported depth data and incorporation of new bathymetry data holdings will better support NGA’s Safety of Navigation products.”

Applying artificial intelligence and machine learning

Efforts to map the world’s oceans stand to benefit greatly through recent advancements in artificial intelligence and machine learning. 

NGA’s Research and Maritime Safety Office developed the Satellite-Computed Bathymetry Assessment (SCuBA) program to provide critical coastal bathymetry data and improve existing satellite-derived bathymetry tools in near-shore regions that are inaccessible via traditional survey platforms. SCuBA leverages NASA’s Ice, Cloud and Land Elevation SATellite-2 space lidar as a measurement and calibration tool, focusing on coastal areas about which accurate depth information often is lacking. 

"Building upon SCuBA capability, the program successfully demonstrated the application of machine learning techniques for fusion of satellite multispectral-imagery with SCuBA products to derive an improved seafloor map from satellite sensors,” said Monique Walker, Ph.D., NGA Research and Development.

Overall, the integration of AI and ML into bathymetry is transforming the field, allowing us to gather important information from underwater environments and make informed decisions for Safety of Navigation and sustainable marine resource management, said Keating and Mahmud.

So, what?

If someone has never been on a ship or sailed the seven seas, what do they stand to gain from increased bathymetric data?

Ocean shipping is the primary method of transporting goods for the global economy. Improving accurate bathymetric information on the depths of water and potential underwater hazards, such as seamount or reefs, is crucial to maintaining safe and efficient maritime transportation. Similar to how drivers in an unfamiliar area may use roadmaps to find their way, mariners use nautical charts based on bathymetric data to guide them.

Although much of the world’s ocean floor still remains a mystery, Crowdsourced Bathymetry aims to help map the remaining parts of the ocean and improve the world’s understanding of the ocean environment. 

“These initiatives will advance NGA’s goal to Know the Earth, Show the Way…from Seabed to Space,” said Mahmud.