Both the Moon and Mars have been more comprehensively mapped than the world’s seas and ocean. Contrary to popular belief, less than 15 percent of the ocean has been measured directly, and only 50 percent of the world’s coastal waters (200 meters deep and below) have ever been surveyed. Bathymetry, knowledge of the depth and shape of the seafloor, underpins the safe, sustainable, cost-effective execution of almost every human activity in the sea, yet most of the seafloor remains unmapped, unobserved, and unexplored.
For context, the United States has about 3.4 million square nautical miles of water within our coastal and Great Lakes jurisdiction. NOAA’s Office of Coast Survey, which is responsible for charting that vast area, averages only about 3,000 square nautical miles of surveying each year. The survey data updates over a thousand NOAA charts. However, hydrographic surveys such as these are expensive and laborious, so the Coast Survey directs resources toward the highest priority sites, which can leave many coastal areas without updates for years.
Forming International Partnerships
Since 2014, the International Hydrographic Organization (IHO) has been encouraging innovative supplementary data-gathering and data-maximizing initiatives to increase our knowledge of bathymetry by including crowdsourced bathymetry (CSB). In this case, the “crowd” encompasses existing mariners.
Most ships are inherently capable of measuring and digitally recording the depth in coastal waters, and an increasing number of vessels are capable of taking measurements in deeper water—both using existing ship equipment. The vision is to tap into the enthusiasm for mapping the ocean floor by enabling trusted mariners to easily contribute data to fill the gaps in current bathymetric coverage.
CSB is used to identify areas where nautical charts are inadequate and proper hydrographic surveys are needed. The key to successful CSB efforts are volunteer observers who operate vessels-of-opportunity in places where charts are poor or where the seafloor is changeable and hydrographic assets are not easily available.
While crowdsourced data may not always meet the accuracy requirements for charting certain areas, the data still hold significant potential for other uses. If vessels collect and contribute depth information, their data can be used to help identify uncharted features, to assist in verifying previously charted areas, and help to confirm that existing charts are accurate. Crowdsourced bathymetry can also provide vital information to support development activities as well as scientific studies in areas where little to no other data exists. Crowdsourcing can be a valuable and efficient way to determine where rigorous surveys need to take place.
Mission: Collect and Share
NOAA chairs the IHO Crowdsourced Bathymetry Working Group and hosts the IHO Data Centre for Digital Bathymetry (IHO DCDB) at NCEI. NCEI has been working over the last few years to enhance the infrastructure and interface of the DCDB to provide archiving, discovery, display, and retrieval of global crowdsourced bathymetry data contributed from mariners around the world.
The purpose of the IHO Crowdsourced Bathymetry Working Group is to encourage all properly equipped vessels to collect bathymetric data as part of their normal operations—in the same way that mariners currently and routinely observe the weather and make other marine environmental observations. With other members, NOAA actively participates in the working group and works to compile a CSB Guidance Document for layman mariners who wish to contribute data to the IHO DCDB. This document will provide volunteer collectors information about CSB, the installation and use of CSB data loggers, data quality issues, and instructions for submitting data to the IHO repository.
A first draft of the IHO guidelines on crowdsourced bathymetry will be distributed for public comment in 2017. The IHO guidelines on CSB are expected to be adopted by the IHO in late 2018.