HYDRO 3-2025 by Geomares Publishing

Exploring the potential of fused imaging and Lidar data for seabed classification

Large-area shallow water and coastal zone mapping opportunities

A new catalogue of Antarctic submarine canyons

How NOAA Coast Survey streamlines workflows for vital navigation products

Shaping the hydrographic profession in Oman

Director Strategy & Business Development

Durk Haarsma

Financial Director Meine van der Bijl

Editorial Board Huibert-Jan Lekkerkerk, Mark Pronk, BSc, Marck Smit, Auke van der Werf

Head of Content Wim van Wegen

Copy Editor Serena Lyon

Marketing Advisors Myrthe van der Schuit, Peter Tapken, Sandro Steunebrink

Circulation Manager Adrian Holland

Design Persmanager, The Hague

Hydro International is an independent international magazine published by Geomares. The magazine and related e-newsletter inform worldwide professional, industrial and governmental readers of the latest news and developments in the hydrographic, surveying, marine cartographic and geomatics world. Hydro International encompasses all aspects, activities and equipment related to the acquisition, processing, presentation, control and management of hydrographic and surveyingrelated activities.

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Something’s missing

While writing this editorial, the last chance in our academic year for handing in research theses was upon me. One student has conducted research into whether AI could aid in the detection of MBES artefacts, and more specifically those produced by sound velocity (SV) and roll. At the same time, I am working on my Professional Doctorate on the specification and verification of coastal construction projects. For this, I am developing a Monte Carlo MBES simulation tool to assess the effects of specifically systematic errors.

For as long as I have been working as a surveyor/lecturer, the importance of SV profiles has been stressed. Much research has gone into the effect of SV in MBES and everyone in the industry seems to agree that it is one of the most important residual errors in surveys. While developing my own

simulator (and while reading the thesis), I started wondering how SV was to be implemented in such a simulator.

I know, at first this may seem obvious. You take a profile, feed it to the software and that is it. But is it? I wondered how software copes with the changing altitude of the MBES in tidal waters. In other words, as the water rises, what happens to the ‘zero’ of the profile entered in the software? While I still need to ask the various software developers how they handle this, from the manuals of some of the main vendors I surmised that the process is exactly as described. The profile is taken from the ‘waterline’ down. This becomes even clearer when looking at the SV sensor at the MBES head, which can be inserted into the profile at the ‘depth’ of the transducer.

At the same time, I started to wonder whether this was an issue. To test this, I took some data from an older thesis of one of my students, Raoul Michels. His research was on the applicability of SV profiles in the Port of Rotterdam, mainly in tidal waters. To support his research, he took multiple SV profiles during different tidal stages and at different locations in the port. I processed these profiles both with and without a tidal correction. In other words, rather than referencing the profiles to the waterline, I referenced them to chart datum (in this case the Dutch NAP).

This showed that the SV profiles are much more stable when referenced to chart datum than when referenced to the waterline. Not entirely surprising, but again, from what I could see in software manuals, not considered in the majority of if not all hydrographic acquisition software. Have I stumbled on an opportunity or is the actual processing of SV profiles more complicated than I derive from the manuals? I will approach the various manufacturers for more information soon…

The above is just a small part of my research, with most of it focusing on how coastal construction works are verified during the acceptation stage. In other

Sound velocity profiles taken during different tidal phases referenced to the waterline and chart datum (NAP).

words, does the client get what the client has asked (and paid) for? My research is now in the execution phase after an extensive literature review into the ‘state of the art’. The literature review produced two main findings. The first is that much is written about specification and survey verification, but seldomly in the same document. There are (if I may say so) decent books about hydrographic surveying and there are very good books on designing

coastal constructions and how to specify works. However, I have not been able to find one document that was a) up to date and b) encompassed all aspects. Nevertheless, all the necessary knowledge is available.

The second finding is that there are many parties involved in construction work. Not just the client and the contractor, but usually also a designer or engineer. Among those main parties, the civil engineering work, which includes specifications, is spread over different people. For example, one engineer makes the design, another is responsible for testing it in a hydraulic laboratory or software model, and yet another writes the specifications. Contract award may be done by another engineer, who may or may not be involved with the execution and acceptance of the project for the client. The contractor has its own engineer during the

execution, and so forth. Am I missing a group of professionals here? Yes: the hydrographic surveyors. On most projects I have been involved in, the surveyor comes into play when the contract is ready for execution (and thus designed, specified and awarded). This contract sometimes has almost impossible survey requirements, which then require extensive discussion while the works are constructed: not necessarily ideal.

One important question, apart from many smaller technical/survey questions that I have in my research, is ‘why’. Why are specifications so often less than possible and why are surveyors not involved in writing them more often? Your suggestions are more than welcome!

I hope I have given you some food for thought. Happy reading!

Huibert-Jan Lekkerkerk Technical editor, Hydro International info@hydrografie.info

Headlines

The Bahamas joins IHO, setting course for national hydrographic service

The International Hydrographic Organization (IHO) has welcomed a new Member State: the Commonwealth of The Bahamas. By joining the IHO, the island nation aims to establish a national hydrographic service and gradually build the technical capability to meet its obligations under the International Convention for the Safety of Life at Sea (SOLAS) on its own. The move follows the government’s commitment to strengthening hydrographic capacity as part of its broader maritime policy goals. “As new members of the IHO, we look forward to collaborating with other Member States and the organization to enhance hydrographic capabilities, share knowledge and contribute to global maritime safety and efficiency,” said Kimberley Lam, head of the Maritime & Ocean Affairs Bureau at the Ministry of Foreign Affairs. IHO director Luigi Sinapi: “For the Commonwealth of The Bahamas, being a Member of the IHO represents not only an opportunity to improve the Maritime National Policy, but above all a unique opportunity to become part of an international organization where cooperation and knowledge of the marine environment represent the real added value for domestic progress and sustainable development of a national economy that has the ocean as its greatest source of wealth and well-being.”

Meeting of The Bahamas’ national stakeholders on hydrography. (Image courtesy: Commonwealth of The Bahamas)

University of Rhode Island students discover historic shipwrecks

A team of eight students, scientists and engineers from the University of Rhode Island (URI) recently returned from the first survey of known shipwrecks in the Lake Ontario National Marine Sanctuary. Using the university’s new, state-of-the-art remotely operated vehicle (ROV) – aptly named Rhody – the student-led team documented 17 shipwrecks. Having embarked from Oswego, New York, aboard the research vessel Lake Guardian, which is owned and operated by the Environmental Protection Agency, the team discovered several new shipwrecks while mapping the lakebed. The ultra-high-resolution surveys conducted at each site will aid the National Oceanic and Atmospheric Administration (NOAA) in identifying and preserving these relics. The URI team was joined by maritime archaeologists from NOAA’s Office of National Marine Sanctuaries, which funded the project through the NOAA Ocean Exploration Cooperative Institute (OECI).

OceanAlpha’s L25 USV achieves long-range survey milestone in Malaysia

Dutch navy adopts AUV tech from Lobster Robotics

In late June 2025, OceanAlpha’s L25 marine uncrewed surface vehicle (USV) successfully completed its first public demonstration in Malaysia, showcasing its advanced marine survey capabilities in real-world conditions at Port Klang. The event, attended by over 60 maritime industry leaders, marked a significant step forward for autonomous survey operations in the region. The L25 USV directly addresses critical constraints for offshore marine surveys: crew dependence and the costly support vessels typically required for operations beyond the line-of-sight (LOS) control range. By successfully conducting a survey mission 33 kilometres offshore while maintaining continuous, stable satellite communications and real-time payload data transmission, the L25 validated reliable over-thehorizon (OTH) capability, which is essential for large-scale or remote survey areas. In the congested waters of Port Klang, the vessel’s advanced perception systems enabled autonomous navigation around moored vessels while dynamically adjusting course to maintain safe distances from high-speed marine traffic. The L25’s integrated automated towfish system demonstrated seamless deployment and retrieval of sidescan sonar equipment, eliminating traditional manual winching requirements and reducing operational risk.

The Royal Netherlands Navy has become the launch customer for Lobster Robotics’ underwater drone, Scout, following the signing of a rapid adoption action plan (RAAP) agreement at the NATO summit in The Hague. The agreement was signed by Deputy Minister of Defence Gijs Tuinman and Lobster Robotics CEO Stephan Rutten. As Lobster Robotics’ first military-grade autonomous underwater vehicle (AUV), this version of Scout will be tailored for naval reconnaissance and seabed object detection. Scout combines high-resolution optical imaging and mapping systems to locate and identify seabed features with exceptional precision. Lobster Robotics, a Dutch high-tech company, designs, manufactures and rents out fully integrated underwater drones that blend robotics, automation and advanced data processing – eliminating the traditional trade-offs between scale, accuracy and efficiency. The militarized Scout will allow the Royal Netherlands Navy to conduct remote and continuous seabed inspections. It can identify unknown objects, mine-like threats or infrastructure damage without exposing personnel to risk. A recent case study showed that using the underwater drone can deliver imagery up to 20 times faster than is possible with divers. Its capabilities provide faster, safer and more consistent results compared to traditional diverbased surveys.

Lobster Robotics CEO Stephan Rutten and Deputy Defence Minister Gijs Tuinman signed a RAAP deal at the NATO summit, making the Royal Netherlands Navy the first Scout underwater drone customer.

From left, Quinlan Fahy of the University of Maine; Joseph Bevilacqua, a Master’s degree student in URI’s Graduate School of Oceanography (GSO); David Casagrande, a marine development engineer from GSO; and Benjamin Rahming, a GSO PhD candidate, safely recover Rhody after a successful dive. (Image courtesy: Marley Parker)

OceanAlpha’s L25 USV showcasing its advanced marine survey capabilities in real-world conditions at Port Klang, Malaysia. (Image courtesy: OceanAlpha)

Hydrographic authority orders Exail’s new long-range USV

New SatLab solution enhances USV-based multibeam surveys

Since its debut in 2017, Exail’s DriX USV has logged more than 500,000 nautical miles in some of the world’s most demanding maritime environments, the company reports. (Image courtesy: Gilles Martin Raget)

Exail has secured the first sale of its new long-range uncrewed surface vehicle (USV), the DriX H-9, to a major global hydrographic authority that has not yet been publicly disclosed. The deal marks a significant step in the company’s expansion in both commercial and defence markets and underscores the growing demand for autonomous maritime systems. The DriX H-9 builds on the success of Exail’s earlier H-8 model, offering up to 20 days of autonomous endurance, greater payload capacity and enhanced flexibility to support a wide variety of missions. Designed for persistent, over-thehorizon surveys, the H-9 reduces offshore logistics requirements while extending operational reach – capabilities increasingly sought in offshore energy, subsea infrastructure and naval surveillance.The vessel can accommodate multiple geophysical sensors simultaneously, including sidescan sonar, magnetometers, multibeam echosounders and sub-bottom profilers. Its aft launch and recovery system allows the deployment of towed sensors and remotely operated vehicles, while an adaptable mast supports optical systems and advanced communications for maritime domain awareness. A gondola architecture, optimized for hydroacoustic sensors, ensures stable, high-quality data collection. Exail has also developed a common framework across the DriX series, simplifying fleet integration and streamlining maintenance. “With this sale of the H-9, alongside the recent success of the DriX O-16, the DriX series is becoming a true reality at sea –enabling operations from shallow to deep waters, with expanding endurance, the ability to accommodate a wide range of sensors, and the capability to launch and recover various assets,” said Sébastien Grall, head of maritime autonomy activity at Exail.

SatLab recently launched the HydroBoat 1200MB, a compact uncrewed surface vehicle (USV) system designed for 3D hydrographic surveying in inland and nearshore waters. The all-in-one solution combines SatLab’s autonomous vessel platform with the HydroBeam M2 multibeam echosounder, offering a portable system that aims to streamline data acquisition in shallow or confined environments. Developed as a fully integrated unit, the HydroBoat 1200MB brings together navigation, sonar data acquisition, real-time visualization and data management. It is intended to support small teams in conducting geospatial reconnaissance and hydrographic assessments with minimal setup and reduced operational complexity. According to SatLab, the system supports a seamless workflow from survey planning to final deliverables. An integrated inertial navigation system (INS) provides roll, pitch and yaw measurements without requiring field calibration. Real-time data visualization capabilities allow users to view high-resolution 3D point clouds, bathymetric profiles and sidescan imagery across multiple devices, supporting on-the-fly quality control and immediate decisionmaking in the field. The HydroBoat 1200MB also incorporates SatLab’s proprietary SPIN (sound speed profile inversion) technology, enabling real-time sound velocity correction without the need for separate sound velocity profilers.

The HydroBoat 1200MB is a compact USV tailored for 3D hydrographic surveying in shallow and nearshore waters. (Image courtesy: SatLab)

Egypt advances digital navigation with new S-101 test datasets

The Egyptian Navy Hydrographic Department (ENHD) has released two new S-101 test datasets, marking a significant milestone in Egypt’s ongoing efforts to modernize its hydrographic services and strengthen maritime safety. The datasets cover the strategically important ports of Alexandria and Port Said, two of the country’s most dynamic maritime hubs. This release underscores ENHD’s commitment to advancing digital navigation and reflects its broader strategic objective to provide state-of-the-art navigational tools that enhance both safety and operational efficiency at sea. By adopting the S-101 standard – part of the next-generation S-100 framework – the department is aligning national hydrographic capabilities with global best practices and technological developments. As Egypt’s official representative to the International Hydrographic Organization (IHO), ENHD continues to play a pivotal role in shaping the future of global hydrography. The release of these datasets demonstrates Egypt’s proactive approach in embracing digital transformation and enhancing its stature within the international maritime community.

Head of Oman National Hydrographic Office receives 2025 Alexander Dalrymple Award

The UK Hydrographic Office (UKHO) has honoured Captain Ahmed Al Badi, head of the Oman National Hydrographic Office (ONHO) with the prestigious 2025 Alexander Dalrymple Award, recognizing his outstanding contributions to hydrography. The award was presented during a celebratory ceremony on 6 August. Captain Ahmed Al Badi was invited to the UKHO, where he was presented with this year’s award. Hosted by the UK’s national hydrographer and director of data acquisition and defence at the UKHO, Rear Admiral Angus Essenhigh OBE, the presentation was attended by members of the wider UKHO team as well as by Colonel Said Al Mamari, assistant military attaché from the Embassy of the Sultanate of Oman. The Alexander Dalrymple Award committee recognized Captain Ahmed Al Badi’s ‘impressive strategic vision and leadership’ in leading ONHO in the S-100 space and forming a five-year implementation plan –the first of its kind for a member of the Regional Organization for the Protection of the Marine Environment (ROPME) Sea Area Hydrographic Commission (RSAHC). As a result of this, Captain Al Badi was elected the RSAHC’s first S-100 coordinator.

Commenting on the award, Rear Admiral Angus Essenhigh said: “The decision to present Captain Al Badi with the award this year was unanimous; my fellow Committee Members and I were all impressed with his strategic vision and leadership in developing the OHNO, particularly with regard to preparedness for the S-100 data standard and their contributions regionally within the ROPME Sea Area Hydrographic Commission.”

The new Egyptian S-101 datasets incorporate an advanced data model along with improved portrayal features. (Image courtesy: Egyptian Navy Hydrographic Department)

Ireland’s Marine Institute to help map Barbados’ ocean territory

Ireland and Barbados are deepening their partnership in marine science and sustainable ocean management. This summer, experts from Ireland’s Marine Institute are deploying the RV Celtic Explorer to begin mapping the seabed within Barbados’ exclusive economic zone. The work follows a newly signed memorandum of understanding (MoU) between the Marine Institute and Barbados’ Coastal Zone Management Unit. Under the MoU, the Celtic Explorer will carry out a bathymetric survey to chart water depths and underwater features, assess seafloor resources and provide vital data to support the development of a marine spatial plan for the sustainable use of Barbados’ marine resources. The framework of the agreement provides for the participation and engagement of key personnel from the Barbados coastal management unit with the institute’s team of scientists. The knowledge exchange between scientists from both organizations supports the Marine Institute’s contribution to achievement of the United Nations Sustainable Development Goals. The MoU agreement also aligns with the objectives of the Marine Institute’s Our Shared Ocean programme, which supports research, knowledge exchange and capacity building in partnerships with Small Island Developing States. The Our Shared Ocean programme is funded through Irish Aid, Ireland’s programme for overseas development, and managed by the Marine Institute.

Archive photo of the RV Celtic Explorer docked in Galway Harbour, Ireland. (Image courtesy: Shutterstock)

Rear Admiral Angus Essenhigh and Captain Ahmed Al Badi during the Alexander Dalrymple Award presentation. (Image courtesy: UKHO)

Captain Ahmed Al Badi on how marine data is shaping sustainability, security and prosperity

Honouring Oman’s hydrographic journey

By Wim van Wegen, Hydro International

Stretching over more than 3,000 kilometres, Oman’s coastline runs along the Arabian Gulf, the Sea of Oman and the Arabian Sea. It is a maritime landscape of islands, bays, coral reefs and the Strait of Hormuz – one of the world’s busiest and most strategic passages – making Oman’s waters among the most dynamic and complex anywhere. It is therefore no surprise that hydrography plays a vital role in the country’s economic and social planning framework. In this interview, Captain Ahmed Al Badi, head of the Oman National Hydrographic Office (ONHO) and recipient of the 2025 Alexander Dalrymple Award, shares his insights on the challenges and opportunities shaping the profession in Oman.

Congratulations on receiving the 2025 Alexander Dalrymple Award. How do you reflect on this recognition?

Receiving the Alexander Dalrymple Award is both a personal honour and, more importantly, a recognition of Oman’s hydrographic journey over the past three decades. For me, it reflects the dedication and hard work of the men and women at ONHO, who have consistently made great efforts to bring our services up to international standards. It also underscores Oman’s strategic role in safeguarding one of the world’s busiest sea routes. I am especially grateful for the continued support and guidance of the Commander of the Royal Navy of Oman, who has been instrumental in achieving these milestones. This award reaffirms that our vision – anchored in Oman Vision 2040 – is on the right path, balancing tradition with innovation and ensuring that hydrography contributes not only to safer seas but also to sustainable economic and environmental development.

Looking back over the past years, what progress has been made in the work of the Oman National Hydrographic Office? The progress has been both steady and transformative. From producing Oman’s very first nautical chart in 1995 to releasing a full suite of electronic navigational charts in 2019, our journey has been marked by

milestones that placed Oman among the leaders in the region. The inauguration of our modern headquarters in 2021 provided the platform to expand services, host advanced data centres and strengthen research and capacity building. Today, our work goes well beyond navigation safety. We contribute to port development, maritime boundary projects, continental shelf submissions and even environmental protection. Looking ahead, initiatives such as the Marine Spatial

Data Infrastructure and the adoption of the S-100 framework promise to take hydrography in Oman into a fully digital era, directly supporting the country’s growth and sustainability goals.

Can you describe the characteristics of the waters surrounding Oman, and what challenges they present from a hydrographer’s perspective? Oman’s waters are among the most dynamic

The Oman National Hydrographic Office has made significant progress in transitioning from traditional charting to digital products.

and complex in the world, stretching over 3,165 kilometres across the Arabian Gulf, the Sea of Oman and the Arabian Sea. This coastline includes islands, bays, coral reefs and the Strait of Hormuz – one of the busiest and most strategic maritime passages globally. Such diversity makes hydrography in Oman both a national asset and a significant challenge. From a scientific perspective, conditions vary greatly: in the Sea of Oman, warm surface layers overlie saltier waters from the Arabian Gulf, creating sharp sound speed gradients that can bend acoustic beams unless corrected by frequent CTD casts. In the Arabian Sea, the summer monsoon drives upwelling along the southern coast, bringing cold, nutrient-rich water to the surface, and generating internal waves, eddies and strong currents that complicate positioning. Nearshore, sediment and seasonal runoff increase turbidity and reduce acoustic penetration. These factors require hydrographic surveys to remain flexible, with frequent sound speed checks.

How does the hydrographic profession align with Oman Vision 2040, the national framework for economic and social planning for 2021–2040?

Hydrography is deeply aligned with the priorities of Oman Vision 2040, which places strong emphasis on economic diversification, sustainability and knowledge-based growth. Accurate hydrographic

data underpins nearly every aspect of the blue economy – from ensuring safe and efficient maritime transport to supporting fisheries, coastal tourism, renewable energy projects and environmental conservation. ONHO’s work extends beyond navigation safety by enabling national development projects, assisting in port expansion and supporting marine spatial planning in line with international standards. At the same time, hydrographic data contributes to climate resilience by monitoring sea-level rise, coastal dynamics and environmentally sensitive areas. Through initiatives such as the transition to the S-100 framework and the development of a Marine Spatial Data Infrastructure, ONHO is making marine data widely accessible for decision makers across government, academia and industry. In this way, hydrography acts as a strategic enabler of Vision 2040, transforming marine resources into a foundation for sustainable prosperity.

How would you describe the outlook for the hydrographic industry and related fields in your country? Do you see potential for growth?

The outlook for hydrography in Oman is very promising and closely tied to the nation’s economic and environmental priorities. As Oman continues to invest in its ports, logistics hubs, fisheries and coastal tourism, the demand for precise and reliable hydrographic data is steadily increasing. ONHO has already transitioned from traditional charting to digital products such as electronic navigational charts, and is preparing to implement the S-100 data framework and Marine Spatial Data Infrastructure. These advancements will make hydrographic information more accessible and useful across multiple sectors, from shipping and energy to environmental monitoring and research. Regionally and internationally, Oman’s active role in IHO commissions further strengthens its capabilities and partnerships. Looking ahead, ONHO plans to integrate autonomous surface vehicles (ASVs) into its operations, expanding survey coverage and efficiency. Together, these initiatives signal strong growth potential, with hydrography set to become a driver of safety, innovation and sustainable development in Oman.

Attracting a new generation of skilled professionals is a major challenge for the sector worldwide. How is this situation in Oman?

We view this as both a challenge and an opportunity. Oman has invested heavily in building its own hydrographic expertise, training young professionals in hydrography, GIS, oceanography and related sciences. Through partnerships with universities and hands-on training programmes, we are ensuring that the next generation is not only qualified but also passionate about the sea. Initiatives such as the Digital School Atlas bring hydrography into classrooms, inspiring young Omanis to see the relevance of this field to their lives and their country’s future. By offering real opportunities for growth and exposure to international forums, we are creating a pipeline of talent that will secure the sustainability of hydrographic services in Oman.

International collaboration is key in hydrography, for example in implementing the S-100 data standard. What is your perspective on this?

International collaboration is fundamental to the progress of hydrography. No single nation can address the challenges of maritime safety and digital transformation alone, which is why ONHO

Captain Ahmed Al Badi is presented with the Alexander Dalrymple Award by Rear Admiral Angus Essenhigh. (Image courtesy: UKHO)

places great importance on working closely with regional and global partners. A key example is the implementation of the S-100 framework. Oman became the first member of the ROPME Sea Area Hydrographic Commission to develop a comprehensive five-year S-100 implementation plan, and I was elected as the Commission’s first S-100 coordinator. This reflects our strong commitment to shaping the future of digital marine services. The UK Hydrographic Office also recognized ONHO’s collaborative approach, particularly in prioritizing knowledge-sharing and ensuring compliance with international standards. Beyond S-100, Oman has hosted several IHO capacitybuilding events, providing opportunities for training and regional cooperation. For us, collaboration is not simply about technology – it is about building a resilient global hydrographic community that benefits all.

What do you currently see as the most exciting developments in hydrography?

One of the most exciting developments in

hydrography today is the transformation from traditional paper charts to a digital, interconnected environment. The implementation of the S-100 framework, for example, will allow hydrographic data to be layered with meteorological, oceanographic and environmental information, creating a richer picture for mariners, planners and decision makers. For Oman, this is particularly relevant as ONHO prepares to launch a Marine Spatial Data Infrastructure that will make national marine data widely accessible online. Another exciting area is the use of autonomous survey technologies. ASVs and autonomous underwater platforms equipped with advanced sensors are enabling faster and safer coverage of areas that were once difficult to access. These tools expand the scope of hydrography beyond navigation safety to applications in climate monitoring, renewable energy and marine science. Together, these developments mark a new era of hydrography as a data-driven enabler of sustainable growth.

The technology to capture hydrospatial data is evolving rapidly. Are there particular solutions you would like to see implemented in Omani waters?

In Oman, we are focused on adopting technologies that increase efficiency, expand survey coverage and improve data quality. A key solution we are preparing to implement is the wider use of ASVs, which can safely and cost-effectively survey coastal areas, ports and offshore regions where conventional ships face limitations. These platforms, combined with autonomous underwater systems, will give us the flexibility to work in challenging environments and extend coverage in areas that remain poorly charted. Another priority is advancing the Marine Spatial Data Infrastructure, which will provide a single, integrated national platform for marine data, accessible to government, academia and industry. By pairing modern acquisition tools with digital data integration, we can support not only navigation but also environmental monitoring, coastal development and

Oman’s waters, stretching over 3,000 kilometres across the Arabian Gulf, Sea of Oman and Arabian Sea, are among the world’s most complex and require advanced hydrographic surveying.

scientific research. These solutions will place Oman at the forefront of hydrospatial innovation and ensure that our waters are managed sustainably.

About Captain Ahmed Al Badi

Captain Ahmed Al Badi is the head of the Oman National Hydrographic Office (ONHO), where he has led Oman’s transformation into a regional and global leader in hydrography. Under his leadership, ONHO developed the first five-year S-100 implementation plan in the ROPME region. He was elected as the region’s first S-100 coordinator, reflecting Oman’s proactive role in shaping the future of digital hydrography. In 2025, Captain Al Badi was honoured with the Alexander Dalrymple Award, recognizing the collective achievements of ONHO in advancing hydrography, strengthening international cooperation and supporting Oman Vision 2040. He is also dedicated to building national capacity, expanding opportunities for civilian and female hydrographers, and ensuring that ONHO continues to serve as both a guardian of maritime safety and a driver of innovation and sustainable growth.

Looking ahead, what is your ambition for the Oman National Hydrographic Office by 2040, and what steps are needed to achieve it?

By 2040, my ambition is for ONHO to be recognized as a global centre of excellence in hydrography and marine data management. We aim to provide fully integrated digital services that extend far beyond navigation, supporting national security, climate resilience and the blue economy. Achieving this requires several steps. First, we must continue to invest in advanced technologies such as ASVs and data-driven platforms. Second, we must fully implement the S-100 framework and establish a mature Marine Spatial Data Infrastructure, ensuring that marine information is accessible in real time to all stakeholders. Third, we must strengthen human capital through training and capacity building, including empowering young professionals and supporting women in hydrography. Finally, active participation in international cooperation will ensure we remain aligned with global standards. By 2040, ONHO will not only meet Oman’s needs but also contribute meaningfully to international ocean governance.

Is there anything else you would like to share with the readers of Hydro International?

I would like to stress that hydrography is no longer a niche technical discipline – it is a foundation for safety, sustainability and prosperity. In Oman, hydrographic data supports a wide range of national priorities, from port expansion and fisheries to climate adaptation and renewable energy. ONHO has worked hard to build national capacity and adopt international standards, ensuring our products serve both local needs and global users. Looking forward, our focus is on innovation, digital transformation and collaboration. The integration of ASVs, the transition to S-100 and the creation of a Marine Spatial Data Infrastructure are all part of this future. But perhaps most important is the human element – building a new generation of hydrographers who will carry the profession forward. My message to readers is simple: hydrography is vital and, through cooperation, we can safeguard the oceans for generations to come.

How NOAA Coast Survey streamlines workflows for vital navigation products

Unlocking hydrographic data throughput

By Matt Wilson, Tyanne Faulkes and Giuseppe Masetti

Coast Survey’s newly revised hydrographic survey specifications and advanced toolsets streamline workflows, boost automation and enable seamless integration with the National Bathymetric Source (NBS) – Coast Survey’s compilation of best-available bathymetry used across all navigation products. As a result, Coast Survey has driven consistent year-over-year reductions in the time required for data throughput. Final processing, packaging and delivery from field units to the shoreside branches is 65% faster in 2025 than in 2021, and data quality review and delivery from the branches to the NBS is 74% faster in 2025 than in 2021.

The NOAA Office of Coast Survey provides navigation products and services that support maritime commerce, keep people safe and secure and protect coastal environments. Timeliness is critical in meeting these objectives, which is why Coast Survey is committed to accelerating and optimizing the delivery of these products and services. It is imperative for Coast Survey to be able to rapidly ingest, qualify and integrate this data (measured collectively as ‘data throughput’) into navigation products and services. This data originates from hydrographic data collected not just by NOAA but also over 150 external data providers (comprising tens of thousands of individual survey contributions).

The comprehensive, multi-year overhaul of the hydrographic survey specifications and deliverables, or HSSD, published publicly in 2024 leveraged the use of S-100-based metadata and universal licence tags, enabling rapid and scalable data qualification and handling. The document also underwent a significant reduction in length (with a 53% reduction in page count), and was made more accessible through both PDF and online HTML formats.

To support the new HSSD, HydrOffice QC Tools 4 and other critical tools

were released, with specifications and software co-developed to ensure optimal compatibility. Altogether, QC Tools 4 fully or partially automates ten distinct sections of the new HSSD. The development team continually receives suggestions and requests for additional automation from both NOAA users and the broader global user community.

Modernized specifications

Ocean mapping capabilities are continually evolving. The specifications that dictate these must – at the survey and product level – therefore also evolve. The HSSD represents NOAA’s implementation of the International Hydrographic Organization (IHO) standards for hydrographic survey and product specifications. The fully revised

HSSD, first published in 2024, marked the largest overhaul of the document in more than 20 years. This comprehensive rewrite ensures full compatibility with advanced, data-driven processes that embrace automation and standardization.

The new HSSD adopts S-100-based metadata attributes to describe data quality in terms of coverage, uncertainty and feature detection. This metadata framework has been incorporated throughout the entire Coast Survey workflow, ensuring seamless consistency and compatibility from specification to final product. As a result, the requirements, evaluation, ingestion and synthesis of bathymetric data for product creation are all accomplished in the same S-100 metadata framework, eliminating the

Figure 1: The HSSD is available in PDF (left) and HTML (right) formats. The latter is accessible via the QR code (centre).

need for metadata translation or conversion at any stage of the workflow.

Coast Survey ingests vast amounts of data generously contributed by external providers, who range from other NOAA offices and federal partners to regional and state initiatives, universities, private sector surveyors, port authorities and beyond. Thus, it was imperative for data sharing to become much more simplified. Traditional models that relied upon custom legal agreements were laborious, time-consuming and often did not sufficiently clarify terms for third-party use. The modernized data sharing approach in the new HSSD embraces the use of universal data licences, wherein a data provider applies a well-known and recognized licence to their data. This ensures that Coast Survey and all third-party users are properly informed of the terms of use, without requiring any meetings or legal reviews. The known licence terms enable automated handling of the data – recognition of the licence makes it ‘machine readable’; that is, an automated process was built and implemented to handle data under the known licence type. This shift makes data sharing and data handling vastly more simplified, streamlined and scalable.

To further facilitate data contributions from external providers, the new HSSD provides a general framework for submitting data of all types to Coast Survey, not specific to any type of sensor, and not restricted to any type of survey (e.g. safety of navigation surveys). Ideally, this opens the aperture for more external data submissions by clearly defining minimum submission requirements alongside what is maximally expected of a hydrographic survey conducted for safety of navigation. Additionally, the S-100 metadata framework in use has the attributes ‘decoupled’ for a more flexible data qualification. For example, the lack of uncertainty calculations in an external data submission would not by itself degrade the feature detection capabilities exhibited or the bathymetric coverage achieved in a survey.

The HSSD document itself was made much more concise, and reduced to focus solely on technical specifications. Guidance, procedures and best practices (which had accumulated over the years in the legacy HSSD) are instead maintained in more applicable references (e.g. Standards of Ocean Mapping Protocol, Field Procedures Manual and vendor documentation). This results in a more focused document that is not redundant with other

Figure 2: Coast Survey throughout the years: operating a projection ruling machine in the WWII era (left), onboard the NOAA Ship Surveyor in 1990 (centre), and a Navigation Response Team vessel in 2025 (right), superimposed on historical charts (left and centre) and the modern-day National Bathymetric Source (right).

ArcGIS brings geographic dimension to big data

Big data analytics has significant applications in hydrography, leading to smarter, safer and more efficient maritime operations. ArcGIS brings a geographic dimension to big data, allowing you to create manage, and analyse vast amounts of spatial and temporal information. This includes survey data, pipeline and cable laying information, port infrastructure, bathymetry and sedimentation data, and more.

Easily navigate big data archives

ArcGIS allows you to manage and analyse massive amounts of data in a single searchable archive so that you can obtain a common operational picture by unifying port infrastructure data with navigational charts and other spatial data.

Big data analytics

ArcGIS enables you to improve operational efficiency, reduce costs and enhance sustainability. Analyse massive amounts of 2D and 3D data for temporal sedimentation patterns, optimize dredging operations, and track cargo in real time.

Share and visualise big data on the web

In ArcGIS, you can visualize, interrogate, and share data using easily configurable web applications. Your data can be shared across your organization, with stakeholders or the public, enhancing collaboration and supporting data-driven decisions with the best available information.

Automatically generate S-100-based products

ArcGIS provides tools to automate the generation of standard products such as S-102, S-101 and S-57 from the latest survey data. Ensure your content is always up to date and compliant with international standards for enhanced safety of navigation and improved efficiency.

Explore how ArcGIS modernizes maritime organizations:

Figure 3: The functions in QC Tools (left) scan bathymetric grids, features files and data submission to ensure hydrographic data meets accuracy and completeness requirements as defined by the specifications. QC Tools 4 is compatible with the new HSSD (release announcement; centre). The QC Tools team is composed of Dr Giuseppe Masetti (lead developer; top right), Tyanne Faulkes and Matt Wilson (developers; centre and bottom right, respectively).

resources, and it is easier for users to find the information they need. Additionally, the HSSD is maintained in Adobe RoboHelp, which offers one-click export to both PDF and HTML versions, the latter of which offers a wiki-like experience to view NOAA hydrographic specifications. Because of the rapid update capability, new HSSD versions are released on an as-needed basis, and potentially midseason, to disseminate critical information to surveyors.

Following a guideline of letting digital data speak for itself as often as possible, without human encroachment, reporting requirements in the new HSSD were substantially reduced from the legacy version. Initially, only an XML metadata file was produced; however, in response to user feedback, a more human-readable PDF report has since been added. Despite this addition, the reporting requirements remain intentionally minimal, aligned with Coast Survey’s datadriven and streamlined approach. Prose is limited to aspects that cannot be directly inferred from data or metadata. This balance is still being refined, however, and working groups within NOAA are actively engaging with surveyors and end users to determine the best equilibrium between a traditional descriptive reporting style and an automated XML metadata output.

Effective data quality review

HydrOffice QC Tools is a long-standing collaborative effort between Coast Survey and the Center for Coastal and Ocean Mapping and Joint Hydrographic Center (CCOM/JHC) aimed at automating compliance with NOAA hydrographic specifications and, more broadly, identifying common data quality issues across the hydrographic community.

The release of QC Tools 4, a major version update, was strategically aligned with the debut of the overhauled HSSD in 2024, ensuring full compatibility with the new specifications. Other critical tool updates supporting the new HSSD were released at the same time by Coast Survey developers, and these included Charlene (for automated data transfer and processing), Scribble (for automated survey metric reporting) and xmlDR (for streamlined survey metadata generation).

The co-development of these tools alongside the new specifications, combined with real-time field testing, provided critical feedback loops

between writing teams and software developers, to ensure the new specifications effectively support automation.

QC Tools 4 serves as the primary tool to ensure compliance with the HSSD. Within its parameters, a user may set the NOAA quality metrics as defined in the new HSSD, which in turn govern the evaluation criteria of the various automated checks. As with previous versions, QC Tools 4 assesses the core deliverables of a hydrographic survey: bathymetric grids, feature files and the submission folder structure. A list of QC Tools 4 features and functionalities are outlined below (and shown in Figure 3):

• Bathymetric grids are evaluated for compliance with uncertainty, resolution (for VR) and density, while potentially anomalous depth nodes (i.e. ‘fliers’) are also flagged for inspection (see Figure 3).

• Feature files are evaluated to verify correct attribution and ensure that all wrecks, rocks and obstructions have depths in agreement with the underlying grid nodes.

• Data submissions are examined to ensure adherence to HSSD requirements regarding structure, folder names and file validity

• Auxiliary tools support uncertainty calculations and comparisons, provide downloadable custom attribution files tailored to NOAA workflows and offer other specialized utilities.

• A Command Line Interface is also available, enabling integration of QC Tools functions in external applications, including other in-house software utilities and commercial solutions.

Bathymetric Attributed Grids (BAGs), developed by the Open Navigation Surface Working Group (ONSWG), are required deliverables under the new HSSD, and serve as the primary input format into the NBS. Consequently, recent development in QC Tools 4 has placed particular emphasis on BAG Checks, which evaluates BAGs to ensure compliance with the HSSD and their seamless ingestion into

Figure 4: QC Tools Flier Finder employs six different algorithms to detect potentially anomalous depths in bathymetric grids. As shown above in overhead (top) and 3D (bottom) views in QPS Qimera software, suspect nodes are ‘flagged’.

the NBS. A list of BAG Checks functionality is outlined below.

• Structure validation: BAGs are evaluated for proper structure in terms of metadata, elevation, uncertainty and tracking list.

• Metadata checks: Additional BAG metadata checks ensure the proper encoding of the coordinate reference system, as well as for the inclusion of survey start and end dates.

• Node integrity checks: All BAG nodes are scanned to ensure the presence of elevation and uncertainty, with specific checks for negative or unrealistically high uncertainty.

• Compatibility checks: Additional checks to ensure compatibility of the BAG with the Geospatial Data Abstraction Library (GDAL) version in use by NOAA.

BAG Checks offers two profile settings: a ‘General’ profile, aligned with the ONSWG BAG specification, and a more comprehensive ‘NOAA NBS’ profile, which enforces the NBS requirements and flags individual nodes that fail any of the checks.

The NBS has ingested roughly 2,800 BAGs since 2018. NBS data is available to the public as BlueTopo, which is the best-available bathymetry as determined from survey dates and the various metadata attributes (e.g. coverage, uncertainty and feature detection)

About the authors

that are available at each node. BlueTopo is served from NOAA’s nowCOAST, a cloudbased web mapping GIS portal for real-time

Figure 5: The National Bathymetric Source (NBS) as viewed in NOAA’s nowCOAST. A seamless compilation of bathymetry may be viewed as elevation (top centre), uncertainty (top right), bathymetric coverage (bottom right), source survey ID (bottom centre) and several other layers (not shown). Individual tiles (delineated as black lines in the top centre image) may be retrieved, and individual nodes may be queried for the S-100-based metadata attributes (left) that originate from the source survey’s requirements and qualifications.

Matt Wilson, streamlining team lead at the NOAA Atlantic Hydrographic Branch in Norfolk, is focused on the more efficient throughput of hydrographic data towards products and services. He holds an MS in Ocean Mapping from the NOAA-UNH Joint Hydrographic Center and an MBA from Penn State.

Tyanne Faulkes, streamlining team lead at the NOAA Pacific Hydrographic Branch in Seattle, advances hydrographic data workflows through automation and innovation. She blends grit, technical innovation and a passion for mentoring and leadership to drive meaningful change in ocean mapping.

Giuseppe Masetti is an adjunct research associate professor affiliated with the NOAA-UNH Joint Hydrographic Center. His research interests focus on various aspects of hydrography, and he leads the development of the HydrOffice research framework.

meteorological and oceanographic data (see Figure 4). BlueTopo is currently available in all US East Coast, Gulf and Caribbean waters, with the Pacific, West Coast, Great Lakes and Alaska regions to be built out in 2026.

A culture of streamlining

In 1967, HydroPlot, the first fully automated system for hydrographic data collection and processing, was installed on the NOAA Ship Whiting. Since then, Coast Survey has consistently harnessed the power of computing to streamline and enhance hydrographic operations. With advancements in hardware and software capabilities, Coast Survey’s tools evolved accordingly, with Shipboard Data System (SDS) in the 1980s, Hydrographic Data Acquisition and Processing System (HDAPS) in the early 1990s and Pydro in the early 2000s. The current ocean mapping tools developed by CCOM/JHC and NOAA (freely available via the open source Pydro and HydrOffice suites) have been instrumental in enhancing hydrographic workflows.

Coast Survey developers work relentlessly to replace tedious and manual processes with automated workflows, bridging gaps where commercial software lacks the flexibility required to meet Coast Survey’s needs. This continuous focus on streamlining reflects a wellestablished culture within Coast Survey; one that was firmly in place long before the publication of the new HSSD in 2024.

Since its introduction in 2015, HydrOffice QC Tools has seen widespread adoption within NOAA and beyond. It has delivered significant benefits, notably bringing much-needed consistency in the review practices between ship and shore. It has also helped define a clear ‘finish line’ for review tasks, that otherwise is not easy to define. Additionally, it has proven to be highly valuable as a practical tool for familiarizing new personnel with hydrographic survey specifications. Similarly, Charlene, a tool first released in 2016, has revolutionized data management and processing in Coast Survey. By automating workflows and minimizing human error, Charlene has led to substantial improvements in data quality. In 2022, the Hydrographic Data Review (HDR) process was launched at Coast Survey’s shore-based processing branches, resulting in a

Conclusion

With the new HSSD as the foundation for streamlined, data-driven workflows – and tailored toolsets delivered to support them –Coast Survey has drastically improved the speed and efficiency of hydrographic data throughput. This advancement enables the timely ingestion of high-quality data into the NBS and, ultimately, to NOAA’s end users. Aligned with a broader organizational commitment to streamlining, these efforts set a clear trajectory for ongoing workflow optimization, greater scalability and a future-ready navigation product pipeline.

More information

• NOAA Office of Coast Survey, Standards and Requirements (https://www.nauticalcharts.noaa.gov/publications/standardsand-requirements.html)

• HydrOffice (https://www.hydroffice.org/)

• Pydro (https://nauticalcharts.noaa.gov/data/tools-apps.html)

• Masetti, G., Faulkes, T., Wilson, M., & Wallace, J. (2022). Effective Automated Procedures for Hydrographic Data

Promising results in automation, with clear limits and potential

AI/ML boosts hydrographic data processing in SONARMUS

By Witold Kazimierski, Maritime University of Szczecin, Poland

Artificial intelligence (AI) is currently one of the hottest trends in many fields, including GeoAI for the processing of spatial data. This study briefly describes research in one project working to achieve HydroAI – the use of AI/ML methods for the processing of hydrographic data to ease the work of hydrographers and to automate some of the routine tasks. Results show promising automation potential, but also underline where classic algorithms still outperform AI.

The information presented here is closely related to the SONARMUS project. This was a research project, lasting for 12 months, entitled ‘Technology for intelligent processing of hydrographical data acquired with the use of imaging sonar and single-beam echosounder, mounted on autonomous surface vehicle’. It was funded by the Foundation for Polish Science under grant number FENG.02.07-IP.05-0489/23. The project was carried out at InnoPM Ltd., which is part of the Maritime University of Szczecin (MUS), Poland, and all the researchers involved were employees of the MUS Department of Hydrography and Spatial Analysis and the Department of Geoinformatics and Teledetection. They are listed on the project website (www. sonarmus.eu).

The project in a nutshell

The goal of the project was to develop AIbased methods for the processing of sonar and single-beam echosounder data. As part

of this effort, the SONARMUS_app – a visual and testing environment – was developed to enable the qualitative evaluation of the implemented methods and system functionalities.

The technological goal was to propose machine learning (ML) methods and algorithms suitable for various hydrographic data to automate and facilitate the workflow and reduce the hydrographer’s workload during the data processing phase. It was assumed that these methods can effectively handle many typical tasks in a hydrographer’s work.

The project included three main phases: workflow analysis and method development with initial training of the algorithms; new data acquisition and retraining and implementation of the algorithms; and testing and evaluation. One of the main challenges was to gather datasets suitable for training, especially for imaging sonar.

The data was acquired using two MUS research platforms. These are the inland survey research vessel HYDROGRAF XXI and the autonomous surface vehicle MINIMUS (see Figure 1). Survey equipment included the Edgetech 4125 SSS, the StarFish 992H Hull-Mount System for ASV, the EA400 single-beam echosounder and the Echologger EU400 for ASV with additional auxiliary sensors. The survey areas included inland waters of the Odra River around Szczecin with depths typical for harbour areas, and various objects in the riverbed.

AI/ML approach for hydrographic data processing

GeoAI, understood as the application of AI to handle geospatial data, has been proven as an interesting solution for various marine-related problems. AI, or more widely speaking, ML methods are however computationally demanding, and as such are not suitable for all applications.

Therefore, the first task in the project was to analyse the process of various forms of hydrographic data handling and to extract the steps in which AI could be useful. Then, suitable algorithms were proposed. The project’s scope covered the handling of sidescan sonar and singlebeam echosounder data (SBES). The use of AI made it possible to create a SMART interface in which most processing steps are automated and final products are created for the user.

Figure 1: Platforms used in the research: a) HYDROGRAF XXI, b) MINIMUS.

In the case of sidescan sonar, typical final products are target reports, with information about contacts, and sonar mosaics, presenting georeferenced sonograms fused within one image. In the case of SBES, typical outcomes are digital bottom models and depth contour maps. Additionally, surveys often include the processing of data from auxiliary sensors, namely positioning and heading, to filter out outliers. These products are available and automated in SONARMUS. Generally, AI was proposed for sonar image handling, target detection and classification, bathymetric data reduction and interpolation and navigational data processing. For automation of other steps, numerical algorithms were implemented. All the algorithms were implemented with open source libraries for data science in Python.

Sidescan sonar data processing

Sidescan sonar data processing can be effectively handled with AI in the form of images, as some of these methods, such as convolutional neural networks, are designed for images. In SONARMUS, AI was proposed for sonograms’ denoising and for target detection and classification.

For denoising, the Neighbour2Neighbour method, based on the U-net architecture, was proposed and validated. This is a deep learning approach used for denoising images. In SONARMUS, the approach without ground truth was proposed. The results are very good, although the implementation requires some modifications and recalculations related to the sonograms’ resolution and other parameters.

A large part of the work was concerned with target detection on the sonograms and classification – a phase that required both the elaboration of algorithms and the preparation of the training samples database. Selected algorithms, used in data science for detection and classification, were used.

Training data for the detection and classification was gathered in several areas using both sonars. The targets were identified and labelled manually on the sonograms as a whole, and also clipped as snippets. This allowed additional augmentation to increase the volume of the training dataset. Six classes were proposed: tire, boulder, corpse, trash, longitudinal target, wreck, and were artificially

created for the testing cube (1x1x1 metre). In the first step of the research, the focus was on the classification.

During the tests, the following algorithms, all based on convolution neural networks, were analysed for the classification: AlexNet, ResNet50, ResNet34, GoogLeNet and Vgg19, showing that the classification potential is very high for these known approaches, even though the training set was not very large.

Figure 2 shows the accuracy achieved for the training set in each test.

In the second part of the research, the detection component was added to the algorithm, which led directly to the use of the YOLO (you only look once) algorithm. As with the classification, this is based on the assumptions of deep convolution neural networks as a backbone, but with the detection component added. YOLO therefore handles both tasks – detection and classification – during one training process.

The custom implementation of YOLOv8x in SONARMUS was prepared as an additional detection/classification component for the user. The main window of this component is presented in Figure 3.

The implementation enables satisfactory results of detection and classification to be achieved, although the accuracy depends very much on the number of objects of a particular class in the training datasets. Better results can therefore be achieved following training iterations in which additional training datasets are added. The training of the model took a few hours and the detection/classification process in the software is dependant on the implementation and processing parameters of the workstation. However, the timeframe is reasonable and significantly shorter than the manual processing of the sonograms. As a result, the user can produce a report with target position, class, estimated dimensions and IHO classification.

Figure 2: Comparison of accuracy in sonar target detection for various architectures and parameters.

Figure 3: Target classification window in SONARMUS.

Single-beam echosounder data processing

In SONARMUS, SBES data is treated as filtered XYZ points, since the filtering tasks are handled during preprocessing. As a result, the input to SBES processing takes the form of a point cloud, with its density closely tied to the survey pattern. For ASV surveys, a high-density profile can be achieved, making point cloud processing methods particularly suitable in this context. The goal was to provide a 3D surface from which two typical products – the DBM and depth contour map – can be developed. The only setting that the user has to make in the SMART variant is the resolution. SBES processing includes three major steps – data reduction, interpolation and the generation of isobaths.

Reduction aims at deleting part of the data, while retaining the most important data so as not to lose the characteristics of the seabed. Several ML algorithms were analysed, mainly focusing on the clustering techniques and including, but not limited to, self-organizing map (SOM), densitybased spatial clustering of applications with noise (DBSCAN), K-means, agglomerative clustering and autoencoders. Some of these were rejected due to large distortions, and finally the best results were achieved with SOM and hierarchical clustering. For various parameters of the methods and the area, results were achieved that made it possible to reduce 60–80% of the data while maintaining the quality of the seabed model.

Interpolation was the next step. The main purpose of this was to achieve a regular grid from randomly distributed reduced data. The challenge is to achieve a smooth yet accurate surface. For this purpose, selfteaching algorithms were again analysed, including random forest, gradient boosting machine, multilayer perception, general regression neural networks and generative adversarial networks. The methods were analysed based on qualitative and quantitative criteria and also in terms of processing speed and computational burden. Based on this, random forest and gradient boosting methods were chosen for implementation. These provide good accuracy, while maintaining quantitative characteristics of the seabed model. An example of the 3D surface for reduced data is presented in Figure 4a.

The final step was to determine depth contours. This stage was done without AI, using the classical approach based on Gaussian filters for isobath smoothing. It was assumed that the AI implemented in the interpolation stage sufficiently affects the process, making it unnecessary to employ additional AI algorithms for depth contours. The result were highly correlated with interpolation method. An example of a depth contours map is presented in Figure 4b.

Data filtering and preprocessing

While auxiliary information such as heading and position is not directly derived from sonar or SBES, it is still crucial for effective data processing. The GNSS and heading signal tends to be jammed and susceptible to local disturbances, shadowing and spoofing, so that it is important to filter such data prior to the processing of sonar or SBES.

In SONARMUS, it was decided to analyse this data gathered in profiles, using time series analysis methods known from data science. Both numerical and neural approaches were proposed. Numerical filters included the Gaussian filter, moving average, Holt-Winters filter and the Whittaker smoother. From neural filters, mainly recurrent networks were tested, namely RNN (recurrent neural network), LSTM (long short-term memory)

Conclusion

The SONARMUS project led to the development of the demonstrator of a technology for sonar and SBES data processing with the use of AI/ML methods for several processing steps. Particularly valuable results were achieved for target detection and classification on sonograms, as well as for depth data reduction and interpolation. Other steps, such as sonogram denoising, mosaicing, depth contour generation,

- An example of using AI for hydrographic purposes: https://www.hydro-international. com/content/article/mbes-feature-detection-using-machine-learning - Attention-enhanced temporal LSTM network as a sonar position predictor for sidescanning sonar waterfall image: https://ieeexplore.ieee.org/document/11132345

- More about GeoAI: GeoAI in the marine domain, Hydro International - DL methods description: https://openaccess.thecvf.com/content/CVPR2021/papers/Huang_Neighbor2Neighbor_ Self-Supervised_Denoising_From_Single_Noisy_Images_CVPR_2021_paper.pdf

- https://www.ultralytics.com/blog/introducing-ultralytics-yolov8

- Project website (currently only in Polish): www.sonarmus.eu

Figure 4: Final products of SBES data processing: a) 3D interpolated surface, b) depth contours.

outlier detection and smoothing were also automated to reduce the hydrographer’s workload.

The project shows that some tasks can be effectively automated, but that AI is not a solution for everything. In some stages (e.g. preprocessing), numerical algorithms are faster and sufficiently accurate. In other stages, the use of AI requires long training and considerable computational facilities. AI algorithms are also very much dependent on the volume and quality of training data. This seems

About the author

Witold Kazimierski is a navigator, hydrographer and GIS specialist who received a PhD in geodesy and cartography in 2008. He is currently an associate professor and head of department of Hydrography and Spatial Analysis at the Maritime University of Szczecin, Poland, and focuses in his research on data fusion, spatial analysis and USV navigation, also using AI. He is acting head of the SONARMUS project.

The data is specific, so that existing solutions typically need to be additionally trained for this purpose.

Nevertheless, the project has shown that this direction is promising. Very positive feedback on the technology was received during tests performed by experienced external hydrographers. Automated functionalities and the entire workflow were highly rated. Therefore, future work is planned, focusing mainly on the processing of MBES data, the acquisition of additional datasets for further development,

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Figure 5: Preprocessing of depth profile from SBES in SONARMUS.

Rapid mission automation with plug-and-play integration

Ocean Aero uses NEPI for AI-enabled maritime inspection and monitoring

Ocean Aero first partnered with Numurus to bring AI-powered automation to the ocean, using Numurus’s NEPI Engine software platform to rapidly integrate edge-AI processing for 360-degree maritime monitoring. That success proved how quickly advanced mission autonomy could be fielded on Ocean Aero’s TRITON hybrid vehicles. Building on that foundation, Numurus is now expanding on the initial effort to add additional automated mission capabilities into its TRITON platform. These include pan and tilt target tracking, auto-camera stabilization and event triggered data collection automation, all supported by NEPI’s intuitive browser-based user-interface system.

Past work: AI for maritime monitoring

The first collaboration began with a clear challenge. Ocean Aero needed to automate target detection and data collection on its TRITON autonomous surface-submersible vehicles without relying on constant operator input. This required connecting multiple fixed cameras, deploying onboard AI models, automating a high-resolution pan and tilt mounted camera, and streaming actionable information to remote centres.

The system detected and identified maritime threats autonomously and delivered information such as images, speeds and directions to operators. This reduced human workload, shortened response times and validated the power of edge AI for at-sea operations.

Traditionally, this would have meant many months of hardware integration and custom software development for a specific automation solution. With Numurus’s NEPI platform, however, Ocean Aero was able to use ready-to-go drivers, AI deployment tools and automation scripts to rapidly build and demonstrate the solution to customers in just a few months. “The combination of Numurus’s NEPI smart system software, off-the-shelf computer hardware and its responsive engineering support team was a big factor in the success of this project. It saved our internal team a lot of development work we’d otherwise have to do ourselves,” says Kevin Decker, CEO of Ocean Aero.

Current work: expanding mission autonomy

Building on that success, Ocean Aero and Numurus are now tackling new challenges. The focus has shifted from a single use case to a broader vision of smart autonomy for ocean vehicles. Current

Ocean Aero’s TRITON vehicles equipped with NEPI software autonomously detect and track maritime activity.

Edge AI-enabled camera system deliveres actionable real-time monitoring data.

projects include integrating new sensors like thermal imaging cameras, creating adaptive control logic for improved target tracking and image stabilization, and expanding event-driven data collection automation tools able to adjust sensor settings in real time. The pan and tilt automation application has been updated to add significant mission capabilities while maintaining an intuitive user interface for end users.

Recent efforts highlight the value of sensor fusion, where data from cameras, sonar and navigation systems is combined into a unified picture. By managing this complexity, the partnership is enabling vehicles to make faster, smarter decisions in real time. NEPI’s role remains the same: simplifying hardware integration and AI deployment so that Ocean Aero can test, validate and deliver new capabilities quickly.

Technology in focus

At the centre of the story is NEPI, Numurus’s

open-source edge-AI software platform.

NEPI simplifies the integration of disparate, complex software into a single software package that enables solution developers and integrators to bring smart inspection solutions to the market faster.

NEPI provides:

• A library of plug-and-play drivers for oceanographic sensors and payloads

• Integrated AI and automation applications for detection, tracking and event-driven automation and collection

• A low-code environment that lets developers and operators build mission workflows quickly, along with a complete ROS data and controls interface API.

These tools remove the heavy lifting associated with building all the underlying middleware, allowing the rapid development and deployment of inspection automation capabilities into any robotic or other in-field deployment platform.

About Numurus

Numurus delivers turnkey plug-andplay edge AI solutions that simplify smart system development for automation and robotics. Its NEPI software platform and hardware solutions help organizations rapidly connect sensors, integrate AI models and automate real-time actions, without requiring deep programming expertise. With built-in drivers for a wide range of hardware, a browser-based low-code interface and a suite of integrated AI and automation applications, Numurus shortens development timelines from months or years to days or weeks. From industry professionals optimizing operations to researchers accelerating discoveries to students gaining handson experience, Numurus empowers users across science, education and commercial industries to harness the full potential of edge AI.

More information

Interested in testing NEPI for your projects? Send an email to nepi@numurus.com to sign up as a beta tester for the new NEPI NVIDIA Jetson container release and receive a free licence.

Updated pan and tilt automation application adds adaptive mission autonomy to TRITON platforms.

How the ambitious Florida Seafloor Mapping Initiative is setting the standard for our understanding of coastal environments

Lidar + Sonar = a revolution in seafloor mapping

By Ryan Cross, Dave Neff and Karen Hart, United States

There are few regions of the United States as defined by or as dependent upon their coastal waters as the state of Florida. Florida’s annual maritime economy is valued at US$402 billion, incorporating tourism, commerce and trade. Cruise and cargo operations alone contribute to at least US$117 billion and over 900,000 direct and indirect jobs across the state, according to the Florida Ports Council.

At a time when shifting climate patterns are affecting coastal regions around the world in myriad, often undetermined ways, and with

a need to understand coastal vulnerabilities and other issues, Woolpert and partners embarked on the ambitious Florida Seafloor

Mapping Initiative (FSMI), a multifaceted project led by the Florida Department of Environmental Protection (FDEP) to create a high-resolution seafloor surface model of the state’s coastal waters.

Deploying aircraft, ships and uncrewed surface vessels, the team mapped tens of thousands of square kilometres of the Florida coast. Using Lidar sensors from the air and multibeam sonar technology from the sea – a combination of technologies deployed at a scale not previously attempted – the team has generated highly-detailed imaging of Florida’s underwater environment.

Since October 2023, experts and technicians faced down hurricanes, freezing winds and weeks spent on ships far offshore. But with significant and wide-ranging project outcomes expected, the effort is deemed worth the challenges.

Slated for hosting on the website of the National Centers for Environmental Information and the Florida Geographic Information Office, this sophisticated mapping database will help with habitat and ecological management, promote methods for safer navigation and assist with fishery and other resource management efforts. It is also expected to aid with coastal resilience efforts, the identification of precise locations of shipwrecks and other popular underwater tourism sites, and provide a host of yet-tobe-determined returns.

RV Thunder is owned and operated by Woolpert. This purpose-built vessel surveyed in both the Gulf of Mexico and on the Atlantic coast.

What is more, making the data available to the public allows anyone – from recreational fishers to curious students anywhere in the world – to see and experience exactly what lies underneath Florida’s coastline.

Mapping from the air

Woolpert’s topographic-bathymetric (topobathy) Lidar mapping efforts focus on FSMI’s Region 3, covering nearly 27,000 square kilometres off the southern coast of Florida, including the Florida Keys, the remote Dry Tortugas National Park and parts of the south-east Gulf of Mexico. Since October 2023, four aircraft equipped with Leica Chiroptera-5 and HawkEye-5 sensors have conducted five mapping expeditions, collecting seafloor data to depths of 48 metres.

With priorities centred on shallow-water regions, the Lidar imaging has uncovered submerged channels critical for navigation, blue holes and carbonate banks. It also generated detailed datasets for habitat systems and environments crucial to the health of manatee populations, coral reefs and mangrove forests in places such as the Big Sable Creek mangrove forest ecosystem in the Everglades National Park.

The ability of topobathy Lidar to collect huge swathes of data using a single flight line makes it a key tool for completing projects quickly and accurately.

And from the sea

Deploying up to eight boats ranging from

50 to 130 feet in size, the sonar surveying operations have covered nearly 18,000 square kilometres of seafloor in areas within regions 1 (north-east Florida), 5 (the Big Bend region) and 6 (the Florida Panhandle). To improve the efficiency of the sonar operation, sections of the mapping process saw a dual-head setup on ships that supported a wide swathe of surveying, boosting coverage areas to five times the water depth in shallow water.

Woolpert exclusively uses R2Sonic (2022, 2024 and 2026) multibeam sonar surveying technology systems that can scan more than 200 metres beneath the surface of the sea. While some of these coastal areas have been mapped in the past, this project stands out in its ability to deliver higher resolution and image quality than achieved before to establish a new level of clarity. And while past projects have relied on autonomous vessel mapping, this FSMI project is the first of its scale to deploy over-the-horizon autonomous systems, meaning these vessels are operating uncrewed and alone in open water. Satellite technologies such as Starlink enable surveyors and technicians to be on the vessels, virtually.

Project technicians remotely operated the autonomous, uncrewed vessel MC29, which can work for weeks at a time using Starlink communications. Woolpert installed its equipment on the 29-foot-long vessel, which was operated by Chance Maritime pilots, to map around 2,150 square kilometres of seafloor. This remote MC29 operation made

Bathymetric data acquired in 85 metre depths off Florida’s Atlantic coast. The dunes are about 15 metres tall and continue for hundreds of kilometres. the project far more efficient than when requiring a traditional crewed vessel.

Woolpert deployed a ‘follow the sun’ system, whereby data collectors based in South Carolina, Alaska, Australia and Ireland maintained a 24-hour system to collect data remotely and in real time.

Far-reaching goals

The scale and ambition of the FSMI project served up challenges and opportunities to propel new advancements in equal measure. In similar projects, mapping is conducted typically only during the summer months, when surface water conditions are relatively

More than a dozen wrecks were mapped in the bathymetric data including this 170 by 70-metre floating drydock that was sunk in 40 metres of water to create an artificial reef.

MC29 uncrewed surface vehicle that acquired over 2,500 square kilometres of bathymetric data in the Panhandle Region of Florida.

calm. This short mapping season could have turned the FSMI project into a three- to five-year endeavour, but the Woolpert team kept working throughout the year, often in challenging sea conditions.

Florida’s coastal waters routinely face weather not seen in most other parts of the world. For five months of the year, hurricanes can be a major concern for residents, businesses and tourists. Allocating vessels while attempting to anticipate storm tracks as they rolled through western Florida during the second half of 2024 proved to be a challenge for project managers working to keep the FSMI project on track. In October 2024, Hurricane Milton, the strongest tropical cyclone to have occurred anywhere in the world that year, wreaked havoc across Florida’s peninsular coast in the form of widespread damage and fatalities.

Another daunting challenge was managing and processing petabytes of data. Data collection from multiple sensors on up to four different aircraft could have resulted in significant variances in datasets. To remedy this potential obstacle, the Woolpert team automated much of the offshore processing, including such processes as noise removal, to save significant time and align with the project budget. Occasionally, environmental challenges such as water turbidity resulted in the need for reflown flight lines.

Opportunities to innovate

The FSMI project presented the team with more than just challenges; it also offered opportunities for learning and adaptation, opening the door for more innovation going forward. After Hurricane Milton hit the Tampa Bay region, a nearby Woolpert research vessel quickly mobilized to map the artificially dredged shipping channel leading into Tampa Bay to identify any debris blockages. This effort enabled large tanker traffic to quickly enter the bay in the crucial hours and days following the devastating hurricane.

Moreover, in past projects, vessels typically went offshore for days or weeks at a time, returning with massive banks of data. To support a more continuous project schedule, the Woolpert team developed a data workflow plan leveraging automation, autonomy and innovative new technology.

Now, thanks in part to satellite systems such as Starlink, that data can be received and processed in a continuous, steady feed in real time,

About the authors

Ryan Cross is a seasoned geophysicist and NSPS/THSOA certified hydrographer with over 18 years of experience in hydrographic and geophysical surveying. As a senior geophysicist and project manager, Ryan specializes in the integration of advanced spatial data collection and has led complex, multivessel survey campaigns across the US.

Dave Neff is an NSPS/THSOA certified hydrographer and Woolpert maritime market director with over 20 years of experience performing and managing hydrographic survey projects from the eastern, western and gulf regions of the US, as well as internationally.

Karen Hart has a comprehensive geospatial and hydrographic background and has been working in hydrography and geosciences for over 25 years. She joined Woolpert in early 2022 and is the marine geospatial discipline leader, overseeing the company’s topobathymetric Lidar processing, sonar data processing and maritime charting groups.

cutting out potential data transfer bottlenecks and uneven demands for computing power – two issues that can significantly disrupt the flow of a project of this scale.

In addition to the technical learnings the project has presented, the team uncovered a host of critical environmental data points. For example, when coastlines require repair in the aftermath of storms – an issue that many scientists expect to become more prominent in the years ahead – repair crews will know exactly where to look for the large underwater sand deposits essential to completing the projects, thanks to the mapping efforts. What is more, we know that reefs can act as a buffer to protect metropolitan areas from storms and sea surges. Finding and mapping those reefs now means that communities may be better prepared to deal with the adverse effects of severe weather events.

By bringing together a host of contractors and interests to map its state waters, FDEP has displayed remarkable ambition and teamwork. And with an estimated US$28 million annual return on investment, Florida seafloor mapping is an asset that is set to pay off for Floridians today, tomorrow and well into the future.

Seamless topobathymetric Lidar digital elevation model (DEM) of an area of the Dry Tortugas National Park, Florida.

Mapping the Antarctic continental slopes to understand shelf to abyss connectivity

A new catalogue of Antarctic submarine canyons

by Riccardo Arosio and David Amblas

Submarine canyons, carved into continental margins worldwide, play a key role in ocean circulation, sediment transport and marine biodiversity. Around Antarctica, their influence extends to global thermoregulation and ecosystem functioning, yet detailed knowledge remains limited. Using the new International Bathymetric Chart of the Southern Ocean v2 and semi-automatic hydrological techniques, a new study (Arosio and Amblas, 2025) delivers the most comprehensive inventory to date: 332 drainage networks and 3,291 canyon streams, revealing striking regional contrasts shaped by differing glacial histories between East and West Antarctica.

Submarine canyons are widespread geomorphic features found along all continental margins. Typically steep-sided and sinuous, they form narrow, V-shaped valleys with rugged slopes that begin at the continental shelf or slope and extend down to the rise or abyssal plain. Antarctic canyons resemble those elsewhere but are generally larger and deeper, shaped by prolonged glacial activity and the vast quantities of sediment delivered to the shelf by ice. Their development is driven primarily by turbidity currents, which transport suspended sediments downslope at high velocity, scouring the valleys they traverse.

In Antarctica, the combination of steep submarine topography and abundant glacial input intensifies these processes, resulting in exceptionally large canyon systems. These canyons are increasingly recognized as critical to understanding climate impacts, as they enhance mixing and channel focused flows, thereby facilitating exchange between continental shelves and deep ocean basins. Because of their role in water mass dynamics and the climate system, detailed mapping and characterization are essential. Without such knowledge, it is difficult to assess how Antarctic oceanography and the global climate will respond to ongoing and future change. The release of version 2 of the International Bathymetric Chart of the Southern Ocean (IBCSO v2) in June 2022 (Dorschel et al., 2022) provides the most complete and high-resolution regional bathymetry to date, offering an opportunity to update and refine the Antarctic canyon inventory since the work of Harris et al. (2014). The aim of this study was to identify, map and characterize Antarctic submarine canyons on the continental slope using a tailored semi-automatic approach that enables efficient extraction of submarine drainage networks.

A protocol for canyon mapping

Isolated or dendritic valley-like features on the continental slope, up to the detail of the resolution of the bathymetry data, were identified, extracting the main and tributary thalwegs. To achieve this objective, a

Figure 1: Visual representation of the methodology applied for stream extraction. A) Hillshaded bathymetry with Feature-preserve smoothing applied. B) Result of the D8 Flow direction tool on the bathymetry data. C) Result of the D8 Flow Accumulation. D) Result of the Strahler Stream Order tool, which determines the order of the different segments of the drainage network.

semi-automatic procedure using ArcGIS Pro was adopted that included the application of filtering and hydrological tools (see Figure 1). Once the thalwegs were extracted, a custommade Python toolbox – Canyon Metrics – was written to geomorphometrically describe the canyons. The toolbox creates sets of ten equally spaced perpendicular transects to each thalweg polyline and automatically extracts canyon profiles and depth values. The script identifies the lowest point in the profile (real thalweg) and searches for the two closest valley shoulders. Thalweg and shoulders (Figure 2) are then used to calculate the rest of the statistics. Owing to limitations in the multisource bathymetric dataset, shoulder detection was not always successful, particularly in areas of low resolution or with data artefacts. A ‘success rate’ was therefore calculated to quantify the proportion of profiles successfully extracted.

Among the other statistics such as depth, width and slope, canyon cross-sectional shapes were also analysed using curvefitting methods. These shape metrics are important because they provide quantitative measures of valley form, allowing distinctions to be made between V-shaped, U-shaped and more complex cross sections. Such information is critical for understanding canyon evolution, sediment transport pathways and the interaction between submarine morphology and hydrodynamic processes. Quadratic fits describe parabolic forms, where the curvature coefficient indicates whether the canyon is narrow and V-shaped or broad and U-shaped.

The General Power Law method provides an additional, more reliable shape descriptor,

3: Overview of the results of the drainage mapping.

with the exponent (b) also defining profile values near one to represent V-shapes, values of two or greater to indicate U-shaped cross sections, and values outside this range to capture convex or box-shaped morphologies. As these curve-fitting approaches assume smooth profiles and perform poorly in irregular terrains, the V-index was also applied. This metric compares the observed valley cross-sectional area with that of an ideal V-shape. A value of zero indicates a perfect V, positive values reflect U-shaped profiles, and negative values correspond to convex valley walls.

Figure 2: Diagram showing the procedure of transects creation for each canyon profile and the parameters extracted. The canyon depth is calculated from the height of the lowest shoulder to the thalweg. The GPL and quadratic fits give the coefficients of the curves fitted in the canyon transects, while the V-index is the deviation from an ideal V-shaped valley.

Acknowledgements

The authors would like to thank Marta Bono Garcia for her work on the initial phases of the project and part of the mapping. Luca Biffi is thanked for his support in developing a version of Pattyn’s GPL script that allows for batch processing. Riccardo Arosio received funding from the Irish Marine Institute’s research grant PDOC 19/08/03. David Amblas acknowledges the support from the Spanish government through grant no. PID2020-114322RBI00 funded by MICIU/AEI/10.13039/501100011033 and from the Catalan Government Excellent Research Groups grant no. 2021-SGR01195.

IBCSO is a regional mapping project of GEBCO, the General Bathymetric Chart of the Oceans, which is conducted under the International Hydrographic Organization (IHO) and the Intergovernmental Oceanographic Commission (IOC) to produce the authoritative map of the world’s oceans. It is supported by the Nippon Foundation–GEBCO Seabed 2030 Project, launched in 2017, and is also part of the Antarctic research community and an expert group of the Scientific Committee on Antarctic Research (SCAR).

Figure

The geomorphometry of Antarctic canyons

Despite the expanded database underpinning IBCSO v2, bathymetric coverage across Antarctica remains uneven, constraining regional geomorphic comparisons. Nonetheless, analysis of submarine drainage networks and canyons along the continental margin reveals marked contrasts between East and West Antarctica (WA). West Antarctica is characterized by short, simple networks, whereas East Antarctica (EA) hosts dense, dendritic systems (Figure 3). These differences are not attributable to data gaps: 33.7% of WA is mapped at high resolution compared with only 13.8% in EA. Instead, they reflect contrasting shelf geometries and glacial histories. In WA, broad shelves and major drainage basins (e.g. Ross and Weddell Seas) channel convergent ice streams, generating erosive flows that carve deep troughs and deposit large trough-mouth fans at the shelf edge. These fans promoted slope instability and canyon initiation but were later infilled by subsequent glaciations, limiting canyon growth

By contrast, EA’s narrower shelves and smaller basins supported weaker, isolated ice streams, leading to lower sediment flux and allowing canyon systems to persist and evolve into more complex, longer structures. The Prydz Bay margin is a notable exception, dominated by a large trough-mouth fan and lacking canyons directly downslope. The persistence of East Antarctic canyon systems likely reflects both this lower sediment burial and the longer-lived East Antarctic Ice Sheet (EAIS), which sustained prolonged erosion and sediment delivery. The Antarctic Peninsula shows the strongest tectonic imprint, influenced by the South Shetland Trench. Here, steep gradients produce highly incised, short canyons and numerous simple networks. Elsewhere, oceanographic processes further shape canyon morphology.

During glacial maxima, turbidity currents were deflected westward by gravity, contour currents and Coriolis forcing, forming sediment drifts alongside canyon systems (e.g. Bellingshausen region). In interglacial periods, canyons channel dense shelf water cascades, preventing canyon infill and contributing to downslope levee development, though their erosional role remains unclear. Unfortunately, current IBCSO v2 resolution is insufficient to fully resolve these oceanographic imprints. Targeted high-resolution AUV or ROV surveys are required to capture fine-scale seafloor signatures and improve understanding of canyon evolution and sediment dynamics across the Antarctic margin.

Impact on ocean circulation

Antarctic canyons facilitate water exchange between the deep ocean and the continental shelf, allowing cold, dense water formed near ice shelves to flow into the deep ocean, mix with the surrounding water and form what is known as Antarctic Bottom Water (AABW), the coldest and densest water in the world that plays a fundamental role in ocean circulation and global climate. These canyons can also channel warmer waters from the open sea towards the coastline, such as the Circumpolar Deep Water (CDW). This process is one of the main mechanisms that drives the basal melting and thinning of floating ice shelves, which are themselves critical for maintaining the stability of Antarctica’s interior glaciers. When the shelves weaken or collapse, continental ice flows more rapidly into the sea and directly contributes to the rise in global sea level. This study highlights the fact that current ocean circulation models such as those used by the Intergovernmental Panel on Climate Change (IPCC) do not

About the authors

Riccardo Arosio is a senior marine geoscientist at the British Geological Survey. Riccardo’s work focuses on the use of geomorphometry and machine learning to characterize the geology and geomorphology of the seabed, and Pleistocene paleoenvironmental histories.

David Amblas is a marine geoscientist and associate professor at the University of Barcelona. He is an expert in seafloor mapping and seabed–ocean interactions, focusing on polar submarine canyons and their role in ice–ocean dynamics and global climate.

accurately reproduce the physical processes that occur at local scales between water masses and complex topographies such as canyons. These processes, which include current channelling, vertical mixing and deep-water ventilation, are essential for the formation and transformation of cold, dense water masses such as AABW. Omitting these local mechanisms limits the ability of models to predict changes in ocean and climate dynamics.

Conclusion

This study delivers the most detailed geomorphic characterization of Antarctic submarine canyons to date, highlighting fundamental contrasts between East and West Antarctica. East Antarctic canyons are longer, dendritic and more depositional in character, reflecting the earlier onset and persistence of the EAIS. West Antarctic canyons are shorter, steeper and more erosional, shaped by convergent ice streams and broad shelves. Beyond their morphology, canyons are critical conduits for ocean–ice interactions, influencing CDW inflow, dense water export, basal melt and AABW formation. The density of EA canyons suggests a stronger role in ice-sheet stability than previously recognized. Advancing this understanding requires expanded bathymetric coverage in poorly surveyed regions and targeted high-resolution observations to resolve canyon-scale processes with system-wide implications.

References

Arosio, R. & Amblas, D., 2025. The geomorphometry of Antarctic submarine canyons, Mar. Geol., 488, 107608, https:// doi.org/10.1016/j.margeo.2025.107608.

Dorschel, B., Hehemann, L., Viquerat, S., Warnke, F., Dreutter, S., Schulze Tenberge, Y., et al, 2022. The International Bathymetric Chart of the Southern Ocean Version 2 (IBCSO v2) [dataset]. PANGAEA, https://doi.org/10.1594/PANGAEA.937574

Harris, P.T., Macmillan-Lawler, M., Rupp, J., Baker, E.K., 2014. Geomorphology of the oceans, Mar. Geol., 352, pp. 4-24, https://doi-org.sire.ub.edu/10.1016/j.margeo.2014.01.011

Investment in maritime digital future brings busy times for New Zealand hydrographers

The government of New Zealand has made millions of dollars available to develop high-tech navigational products that will transform shipping in the country’s waters. The Maritime Digital Transformation (MDT) initiative aims to revolutionize how mariners interact with data such as electronic charts, water depth information, ocean surface currents and navigational warnings.

Mariners will benefit from enhanced safety, along with improved fuel efficiency and more optimized routing, thanks to these new digital products. To deliver this, LINZ (Land Information New Zealand) and Maritime NZ are working together to roll out the solutions over the next four years. The investment amounts to approximately US$17.5 million.

Joint responsibility for safe navigation

The New Zealand Hydrographic Authority, which sits within LINZ, is responsible for navigation products, including up-to-date nautical charts in New Zealand waters, areas of Antarctica and the south-west Pacific, and tidal and bathymetric (ocean depth) data. Maritime NZ is the national regulatory, compliance and response agency overseeing the safety, security and environmental protection of New Zealand’s coastal and inland waterways. It issues navigational warnings to seafarers across a 50 million square kilometre area as part of the WorldWide Navigational Warning Service.

LINZ and Maritime NZ share responsibility for ensuring that New Zealand meets its obligations under the International Maritime Organization’s (IMO) International Convention for the Safety of Life at Sea (SOLAS), including keeping up with global navigation standards. Through the MDT programme, LINZ and Maritime NZ will work together to implement the new international safety standard S-100, set by the International Hydrographic Organization. The S-100 standard is part of a wider global shift towards eNavigation.

Skilled professionals

To drive forward the MDT initiative, New

New Zealand, shown here on an aerial imagery basemap from LINZ, has set high hydrographic ambitions for the years ahead. (Image courtesy: LINZ)

Zealand is bringing together a new team of skilled professionals. Up to five geospatial specialists will be recruited to begin on 29 October 2025, joining as a dedicated cohort for the MDT programme. Together, they will play a central role in shaping the future of the nation’s maritime navigation services.

Successful candidates will develop specialized expertise in producing and maintaining navigational chart portfolios, processing geospatial data and applying rigorous quality control processes. They will help ensure that New Zealand’s navigational products not only meet current and future international requirements but also support the transition to advanced digital services that keep pace with the needs of modern shipping.

Shaping safer seas

Hydrographic survey work in New Zealand is already well underway, with a major effort planned over the coming years to map 40% of the country’s coastline using topographic

and bathymetric Lidar technology. The focus will be on highly populated coastal areas, regions with significant infrastructure and locations at greater risk of coastal inundation.

The data collected will be used to produce detailed 3D maps of the coastline and adjacent seafloor, creating a baseline to track future changes in coastal areas. This will provide valuable insights into the impacts of climate events and natural hazards such as tsunamis and earthquakes.

The mapping will support decision makers in safeguarding communities and infrastructure, while also enhancing the protection of marine biodiversity through improved habitat mapping.

In light of the MDT initiative, it comes as no surprise that LINZ will also use the data to update nautical charts, strengthening maritime safety – a core element of its hydrographic work programme.

Soundscape around an offshore Dutch platform in the Dogger Bank

What goes bump in the night around an offshore platform?

By Victoria Todd and Ian Boyer Todd, United Kingdom

What happens when the hum of industry meets the bustle of marine life? A new study by Ocean Science Consulting Limited’s (OSC) scientists explores the underwater soundscape around a Dutch offshore gas platform on the Dogger Bank Special Area of Conservation (DBSAC). Using passive acoustic monitoring (PAM), researchers found surprisingly sparse fish vocalizations – even at control sites – suggesting low acoustic activity may be typical of the region. These findings offer vital ecological insights for rigs-to-reefs (RTR) decommissioning and OSPAR-aligned marine management.

The A18 (Figure 1) is a relatively new, unmanned offshore gas production platform operated by Petrogas E&P in the Dutch sector of the North Sea. Installed in October 2015, it sits in approximately 47 metres of water on the edge of the DBSAC. This region is one of the busiest maritime zones in the world, with intense shipping, fishing, wind farm activity and oil & gas (O&G) operations contributing to a complex and noisy underwater environment.

As part of a Petrogas-commissioned cradleto-grave RTR decommissioning study, previous remotely operated vehicle and acoustic surveys around A18 documented rapid colonization by fish and invertebrates – including soniferous species such as grey gurnard (Eutrigla gurnardus) and Atlantic cod (Gadus morhua), as well as marine mammals such as harbour porpoise (Phocoena phocoena) (Todd et al., 2020a; Todd et al., 2021; Todd et al., 2022; Bolgan et al., 2025). However, no prior research had investigated the platform’s underwater soundscape or presence of fish-communicative sounds. It was thought that, since the platform was relatively new, the likelihood of a highacoustic density of breeding fish would be low near the platform, compared to control locations further away.

Figure 1: A18 platform in the Netherlands sector of the Dogger Bank.

2: Locations of C/F-POD/noise recorders at experimental (A18 platform) and control locations in the Dogger Bank Special Area of Conservation. Coordinates WGS’84 decimal degrees.

Study methods

To characterize the underwater soundscape and assess fish acoustic activity, OSC scientists deployed passive autonomous underwater acoustic recorders with a flat frequency response from 2Hz to 384kHz and a sample rate of 48kHz, at three fixed distances from the A18 wellhead: 70 metres, five kilometres and ten kilometres northeast (Figure 2). Recordings were collected continuously from July to November 2022.

Analysis followed a twofold approach. To study the soundscape, long-term spectrogram averages (LTSA) and percentile power spectral density (PSD) plots were used to assess acoustic variability across sites and seasons. These methods helped identify dominant frequency bands and temporal patterns in the soundscape. For fish sounds, manual audio-visual inspection of selected days per month was conducted using Raven Pro software. Fish sound types were identified based on spectral and temporal features and compared with reference recordings from the Global Inventory of Fish Sounds. Principal component analysis (PCA) was used to infer potential species emitting recorded sounds.

Results

Across all three sites, the soundscape was dominated by underwater radiated noise (URN), particularly below 2kHz, with peaks between 300 and 500Hz. No acoustic-mass phenomena, such as fish choruses or low-frequency marine mammal vocalizations, were detected. The soundscape showed strong acoustic similarity between all sites and lacked clear diel (24-hour) or seasonal patterns, with anthropogenic noise most prominent during summer months.

Only two fish sound types were identified (Figure 3). The first, termed ‘pulse series (PS)’, was detected at the 70m and 5km sites, primarily during September evenings (19:00–23:00 UTC). These sounds closely matched those produced by the grey gurnard. The second vocalization, termed ‘low-frequency down-sweep (LF-DS)’, was recorded at all three sites, with acoustic features resembling the grunts of Atlantic cod. LF-DS was emitted throughout the day at the 70m site, and during evening hours at the 5km and 10km sites.

Fish acoustic richness ranged from one to two sound types per site, and abundance never exceeded two sounds per minute. PCA confirmed the likely species attribution for both sound types.

Chrono-anthropogenic noise

This research provides the first characterization of a North Sea underwater soundscape near to and at a distance from a Dogger Bank gas production platform. Results reveal a low-diversity, lowabundance fish acoustic community. The unexpectedly sparse occurrence of fish calls was not confined to the platform vicinity but also extended to control locations, indicating that low levels of acoustic activity may be a broader feature of the Dogger Bank region. This suggests that fish in this area may have naturally low vocalization rates, rather than being reduced acoustically by platform noise. As

Figure

Figure 3: Waveforms and spectrograms of fish sound types recorded during this study. (A) Pulse series (PS) and (B) low-frequency down-sweep (LF-DS) (Hanning window, FFT size 3,200, frequency resolution 15Hz, 50% overlap).

such, attributing low fish acoustic presence solely to anthropogenic disturbance from the platform is not supported by this data.

This is highly significant because most industry-funded monitoring studies do not incorporate control locations; consequently, without controls, a study like this could have been interpreted as the platform having a significantly ’negative’ impact on fish, as opposed to no impact. Nonetheless, the overall low-diversity, low-abundance fish acoustic community discovered here is still likely shaped by chronic-anthropogenic noise in general. The dominance of URN and absence of mass-acoustic events at all locations suggest that the Dogger Bank’s wider intense industrial activity may suppress fish vocal behaviour or limit the establishment of stable spawning grounds.

The laconic nature of these calls is consistent with early-stage colonization, supporting the hypothesis that the relatively new A18 platform ‘artificial reef’ is still in the process of being established

References

Bolgan, M., Todd, I.B., & Todd, V.L.G. (2025): Soundscape and fish passive acoustic monitoring around a North Sea gas-production platform in the Dogger Bank. PLoS ONE 20, e0319536.

Nicolette, J.P., Nelson, N.A., Rockel, M., Testoff, A., Johnson, L., Williamson, L., & Todd, V.L.G. (2023): A framework for net environmental benefit analysis based comparative assessment of decommissioning options for subsea structure: North Sea case study. Frontiers in Marine Science

Todd, V.L.G. (2016). Mitigation of underwater anthropogenic noise and marine mammals: the ‘death of a thousand’ cuts and/or mundane adjustment? Marine Pollution Bulletin Editorial, 102, 1-3.

Todd, V.L.G., Williamson, L.D., Cox, S.E., Todd, I.B., & Macreadie, P.I. (2020a). Characterising the first wave of fish and invertebrate colonisation on a new offshore petroleum platform. ICES Journal of Marine Science 77, 1127-1136.

Todd, V.L.G., Williamson, L.D., Jiang, J., Cox, S.E., Todd, I.B., & Ruffert, M. (2020b), Proximate underwater soundscape of a North Sea offshore petroleum-exploration jack-up drilling-rig in the Dogger Bank. The Journal of the Acoustical Society of America, 148, 3971-3979.

Todd, V.L.G., Susini, I., Williamson, L.D., Todd, I.B., McLean, D.L., & Macreadie, P.I. (2021). Characterising the second wave of fish and invertebrate colonisation and production potential of an offshore petroleum platform. ICES Journal of Marine Science, 78, 1131–1145.

Todd, V.L.G., Williamson, L.D., Couto, A., Todd, I.B., & Clapham, P.J. (2022): Effect of a new offshore gas platform on harbor porpoise in the Dogger Bank. Marine Mammal Science, 38, 1609-1622.

Todd, V.L.G., McLean, D., van Elden, S., Thomas, A., & Todd, I.B. (2025): A new rewilding paradigm: NEBA-CA case study of an end-of-life North Sea oil platform. Annals of Limnology and Oceanography, 10, 022-038.

About the authors

Dr Victoria Todd is managing director and chief scientist at Ocean Science Consulting Ltd, specializing in underwater acoustics, marine mammals, decommissioning and offshore environmental impact. She leads global research and consultancy across industry, academia, defence and government.

Ian Todd is co-director of OSC Ltd, overseeing offshore logistics, instrumentation and operations. He specializes in deploying acoustic monitoring systems and coordinating complex fieldwork for environmental impact assessments in challenging offshore environments.

ecologically. Over time, it is predicted that fish acoustic density will increase, as the platform matures and supports more stable and diverse communities

Significant advancement

This study marks a significant advancement in understanding biophonic patterns in temperate, industrialized marine environments. Findings are highly relevant to RTR decommissioning strategies and the Oslo-Paris Convention for the Protection of the Marine Environment of the North-East Atlantic (OSPAR) framework, which emphasizes the importance of evidencebased decision-making in evaluating ecological benefits of leaving infrastructure in place. This work also highlights the value of PAM for long-term ecological assessment and environmental impact evaluation, particularly in the context of offshore infrastructure and decommissioning. An example of such an evaluation is the Net Environmental Benefit Analysis Comparative Assessment, NEBA-CA (Nicolette et al., 2023; Todd et al., 2025), where noise is considered only in a mitigative context during noisy operations such as conductor driving, unexploded ordnance (UXO) and plugging & abandonment (P&A) (Todd et al., 2020b).

Noise is also not considered in any before-after control-impact (BACI) O&G decommissioning studies (Todd, 2016); consequently, in highly pressured environments such as the North Sea, integrating PAM into environmental management frameworks could improve understanding of ecosystem dynamics and inform monitoring, mitigation and end-of-life strategies. Moreover, development of open-access sound libraries and machine learning tools will be essential to support the scalable analysis of large acoustic datasets. Future studies should explore acoustic monitoring across other offshore structures to build comparative baselines and support evidence-based policy development.

EvoLogics Sonobot 5 USV: expanding capabilities

Geoinformation underpins decision-making in urban planning, traffic and energy infrastructure, disaster prevention and environmental protection. Global challenges such as climate change, resource security and rapid urbanization demand reliable geospatial data, while advances in AI, cloud computing and autonomous systems accelerate its collection and use. These themes define the focus of Intergeo 2025, the leading trade fair for geodesy, geoinformation and land management.

The subsea domain contributes an essential dimension to geoinformation. This is where EvoLogics brings in 25 years of innovation in underwater communication, positioning and robotics. At the centre of the company’s Intergeo showcase in Frankfurt is the compact Sonobot 5 uncrewed surface vehicle (USV) – a versatile platform that extends geodata collection into rivers, lakes, harbours and coastal environments, combining autonomy and advanced sensing with a streamlined, user-friendly design.

Origins

EvoLogics, founded in 2000 and headquartered in Berlin with a US sales office in Yorktown, Virginia, has a long history of blending advanced engineering with bionic concepts. The company’s expertise spans underwater acoustic communication, positioning systems, robotics and integrated sensors.

First introduced in 2011, the Sonobot was conceived to bridge the market gap between hydrographic surveys with handheld tools

and those conducted with large, expensive vessels. Designed for single-person deployment yet capable of collecting professional-grade data, the concept has guided its evolution into today’s Sonobot 5 – a flexible USV platform adaptable to diverse needs.

Technical capabilities

The Sonobot 5 is a foldable twin-hull catamaran, designed for portability without sacrificing stability. The platform supports a wide range of survey payloads. GNSS options include DGPS and RTK for centimetre-level accuracy, with alternatives such as laser tracking with a total station for GNSS-denied environments. Multiple sonar configurations are available – single-beam echosounder, multibeam, sidescan or forward-looking sonar – ensuring that each system can be tailored to specific project needs. For visual data, the Sonobot 5 can be equipped with front-view overwater, underwater, stereo and thermal cameras.

The compact catamaran folds for transport, is assembled without tools and can be launched by a single operator. Once on the water, the USV runs the mission in supervised autonomy, navigating along a preprogrammed waypoint grid with the option for operator intervention over radio control. Mission planning is streamlined through EvoLogics’ dedicated software, which handles sensor parameter settings and survey grid design and provides live data visualization.

Sonobot 5 with multibeam sonar (left), Sonobot 5 with single-beam echosounder, side-scan sonar and underwater camera (right).

The vehicle’s powerful drives enable efficient manoeuvrability and coverage, with survey speeds of 0.5–1.5m/s and a top speed of 5m/s. The communication runs over a redundant mesh WiFi network; the wireless shore station supports real-time transfer of preview data and is available in several versions, including 1.5km, 2.5km and longrange options.

The Sonobot’s robust design is constructed from seawater-resistant carbon fibre, stainless steel and engineered plastics and enables operations in both clean and contaminated waters. With endurance of up to nine hours on a swappable battery pack, the system is equally suited for short deployments and longer, data-intensive surveys.

A notable add-on option for the Sonobot is the AI-based object recognition module, which processes raw sidescan sonar data directly onboard. Detected objects are highlighted in real time in the control software. This system can be cloud-linked, is regularly updated with new object classes and can be trained with user datasets to recognize custom targets.

Whether tasked with bathymetric mapping, structure inspection, environmental monitoring or search operations, the Sonobot 5 is a tool that offers a balance of portability, autonomy and professional-grade sensors.

Novel applications and USBL integration

Since 2015, EvoLogics has experimented with integrating the Sonobot platform with the company’s acoustic positioning technologies. Those early trials laid the groundwork for today’s Sonobot 5 USBL configuration, unveiled in 2024. The Sonobot 5 with USBL features a streamlined, motorized arm that submerges or lifts the USBL antenna as required, fully controlled by onboard software.

By combining survey capability with mobile acoustic networking, the Sonobot 5 extends its role from hydrography to multifunctional operations within EvoLogics’ broader ecosystem of subsea technologies, which opens new possibilities to smart subsea use cases. A Sonobot 5 with USBL can operate as a mobile surface node for EvoLogics’ Diver Navigation System, following divers to ensure they remain within range. It can also serve

Sonobot 5 with USBL (left), Sonobot 5 with single-beam echosounder, side-scan sonar and long-range radio (right).

as a communications bridge for AUVs such as the Quadroin, linking submerged assets to shore control without the need for static buoys.

Use cases in practice

The Sonobot 5’s applications span industries. In inland and coastal waters, it serves as an efficient and reliable solution for hydrographic surveys, mapping channels, harbours and reservoirs. Environmental monitoring missions leverage its flexible payloads to track sediment, map habitats or document pollution. Infrastructure inspections, from bridges to dams, benefit from its mobility and sonar configurations.

Emergency response operations also stand to gain. Equipped with the Diver Navigation System and USBL, the Sonobot can act as a mobile relay for diver teams engaged in urgent tasks such as search and recovery or underwater cleanup. This adaptability underlines why the platform has become one of EvoLogics’ cornerstone technologies.

Scaling Sonobot 5 production

Meeting growing demand requires scaling both the product range and the production capacity behind it. In July 2025, as EvoLogics marked its 25th anniversary, the company completed a major expansion of its Berlin headquarters at WISTA Adlershof Technology Park. The new facility – phase two of the EvoLogics’ campus development – now hosts dedicated serial production lines for EvoLogics’ full portfolio: acoustic modems, USBL and LBL positioning systems, the Quadroin AUV, the Diver Navigation System and, crucially, the Sonobot 5 USV.

This purpose-built production building represents more than added floor space. It provides the infrastructure for EvoLogics to accelerate development pipelines, shorten manufacturing timelines and deliver at larger volumes. For the Sonobot 5, this means faster iteration of new payload configurations and the ability to meet a broader spectrum of customer needs.

By investing in manufacturing capacity, EvoLogics is ensuring that innovations such as the USBL-integrated Sonobot can transition smoothly from prototype to a serial production line, not as one-off systems but as robust, scalable solutions.

Looking ahead

The Sonobot’s evolution from a compact survey tool to a multifunctional platform reflects the company’s approach: practical innovation backed by solid engineering. With the new Berlin facility now online, upcoming developments – from AI modules to expanded payloads and cooperative vehicle interaction – can move faster from design to deployment.

As EvoLogics marks 25 years, the Sonobot 5 stands as both a proven solution and a launch pad for what comes next. At Intergeo, EvoLogics signals a clear focus: innovation paired with scalable delivery for the sector’s evolving needs. To learn more about the company’s solutions, visit EvoLogics at stand 1C040 in hall 12.1.

The crucial importance of the bathymetry echogram for the success of excavation work

Identifying true bottom for reliable dredging results

By José Bartolomeu Ferreira Fontes, Mathias Schlosser and Lígia Maria Simon Falleiros Fontes, Brazil

The Tietê-Paraná Waterway is an important navigable route in Brazil, stretching over 2,400 kilometres. It comprises sections of the Paraná and Tietê rivers and is equipped with lock systems to overcome the elevation differences of the dams. It is crucial for the transportation of goods and passengers, particularly for the transport of agricultural products from states such as Mato Grosso, Mato Grosso do Sul, Goiás and parts of Rondônia, Tocantins and Minas Gerais. Managed by the federal and São Paulo state governments, it is part of the Southeast Logistics Corridor, boosting industrial, tourist and economic development by linking production areas to seaports and Mercosur centres.

Because of climate change and river-level fluctuations, dredging works are essential to ensure the longevity of the waterway. In several stretches along the river, the material encountered is rock, necessitating the breaking and excavation of these rocks to reach the necessary depth. The mapping and quantification of these depths is therefore a daily requirement for a dredging project in the Tietê-Paraná Waterway, where the transport of submerged material is routine and understanding its behaviour during and after activities is a constant challenge.

In this article, we emphasize the importance of the echogram due to its ability to differentiate the underwater bottom based on the characteristics of received acoustic reflections. The experience and knowledge of the hydrographer are crucial for effectively identifying different types of bottom based on this acoustic information. Echogram processing may seem straightforward, but not everyone applies this tool in their dayto-day work. Although it may appear to be old-fashioned, only the echogram represents the true bottom, and can therefore provide certainty about the entire dredging process.

Bottom characterization methods

Various methods of bottom characterization are available, depending on the purpose of classification (e.g. to characterize sediments or detect objects, or to search for buried

objects, paleochannels or underground mineral deposits) (Hamilton, 2001). Traditional equipment allows the recording of echograms on thermal paper (Figure 1). Such echograms are useful, serving as documentary records and aiding in data processing. Using them, it is possible to verify whether a point outside the continuity of the bottom is indeed an obstacle or acoustic noise. The difficulty with this type of product is its handling and preservation

over time. In very large survey areas and over many days of drilling, many paper prints are generated and need to be handled carefully, sequenced and stored. They are also difficult to duplicate and back up. Nevertheless, their use and importance cannot be ignored.

Sounding files are in binary format and can be processed simultaneously with other sounding profiles, if they are defined on the same scale and can be processed

Figure 1: Paper single-beam echosounder echogram 200/24kHz (Fontes, 2010).

or stone left behind?

using the same responsive commands. These files allow for easier interpretation of what is at the bottom or in the water column, as they can be analysed and processed for a more reliable result. Additionally, these files can be copied without loss of quality and without requiring excessive physical space. There is also no risk of running out of paper in the middle of a survey line or of someone forgetting the paper rolls. However, even with digital survey profiles, how can we know where the true bottom is if there is no echogram? If we look at Figure 2, is the bottom consolidated or is there loose material at the bottom? We cannot be sure because we cannot see the nuances of the contours and the behaviour of the acoustic signal at the bottom. The question therefore arises: why is an echogram generated by a single-beam echosounder still important in the era of multibeam echosounders?

There have been many advancements in acoustic applications, such as multibeam systems, scanning sonar, seismic imaging and so on. However, sound propagation remains dominant and the use of all available tools, even the old ones, ensures quality service, especially in the field of dredging. Utilizing all available tools and equipment in their appropriate setting means that dredging activities can be optimized. The use of multibeam echosounders is often mandated to fulfil contractual requirements – sometimes regardless of whether this aligns with the actual needs of the project.

In commercial settings, financial considerations tend to take precedence, leading to the assumption that a single survey

operation.

method might suffice. However, in practice these methodologies are best viewed as complementary. Multibeam and single-beam echosounders are precise and indispensable tools in both small and large-scale dredging activities.

Single-beam echosounders offer an excellent cost-benefit ratio and provide valuable insights into suspended sediments and certain bottom characteristics. This capability is particularly advantageous for identifying fine sediments, analysing their nature and behaviour, and mapping or quantifying their distribution within a given area. Multibeam echosounders, by contrast, deliver comprehensive coverage and significantly higher precision in volume calculations. While they are highly effective at detecting the true bottom of a water body, they are less capable of identifying loose surface layers such as rocks or debris (Figure 3). In the specific project described in this article, single-beam surveys were conducted with one-metre spacing between cross sections to enhance volumetric accuracy.

Dredging project

In this project, in discussions with inspection and supervision companies, the responsible parties mentioned that echograms were no longer necessary. However, we observed that the echosounder was a thermal paper device, and that paper was sometimes not even used during surveys. Hydrographic surveys are regulated by the Brazilian Navy, which published NORMAM 501/DHN to define the rules for conducting hydrographic bathymetric surveys. Under these rules, the use of echogram recording is mandatory, to calibrate

Figure 2: Depth profile without an echogram. What is this? Consolidated bottom

Figure 3: The digital echogram shows the loose stone left behind during the dredging

Figure 4: Digital echogram profile generated by the echosounder at frequencies of 200/33kHz.

About the authors

the equipment and analyse the data to check for possible acoustic peaks.

Before the start of the dredging project, two surveys were conducted using single-beam equipment, one by the dredging company’s research team and the other by our supervision team. The research team used a SyQwest echosounder that was supposed to be loaded with thermal paper, but no paper was used, and only simple depth profile data was produced. Our research team used a Teledyne Odom single-beam echosounder with a digital echogram. The contractual frequency of the echosounder was 200kHz for both surveys. The data was analysed and processed using simultaneous echogram recording. The example (Figure 4) shows a dual-frequency bathymetric profile conducted in a port area where the influence of suspended material is already well known due to the contribution of the nearby estuary to the channel.

The peculiarity of the area, the terrain characteristics and the fact that the area had been worked with dredges in the past, show in its profiles, which report different types of discontinuities in the terrain. The same goes for vegetation on the slopes, as this is a region where the river level varies greatly during dry periods. Survey data profiles must therefore be processed with great care to avoid including features that are not real. Other problems, such as undersized explosions and failures in rock containment, cause loss of rocks in unplanned locations.

These and other circumstances require the correct use and interpretation of the echogram and its nuances. Situations can also be identified where we need to visualize interference in the water column, such as noise from other equipment of the same frequency on the same vessel. Due to seasonality and the associated dry season, some features are absent at certain times of the year, making it possible to compare photographic images

José Fontes, who holds a postgraduate degree in Coastal Management, is a hydrographic and dredging specialist with extensive experience in bathymetry, navigation and maritime works. He focuses on innovative hydrographic solutions that enhance efficiency, safety and environmental responsibility. Over the past 25 years, he has supervised dredging projects and conducted surveys covering 50,000km in Brazilian ports, waterways, and mine dams.

Lígia Falleiros Fontes, DVM, holds postgraduate degrees in small animal medicine, surgery and dermatology. With extensive expertise in diagnostic imaging and clinical interpretation, she contributes to advanced echogram analyses, while her work in regional fauna management provides valuable insights into environmental monitoring and hydrographic applications.

Mathias Schlosser is a consultant and founder of warnow|C. Originally from Germany, he has been working in Brazil since 2007, specializing in hydrographic surveying, dredging work monitoring, data analysis and spatial applications.

with the echogram (Figure 5). Vegetation and loose rocks are easily identified in the echogram. These comparisons contribute to a better understanding and, at the processing stage, ensure that no structure that may represent a risk to the operation and navigation is removed.

The total area of the dredging project surveyed was 15 kilometres in length and 60 metres in width. While there were several differences between the profiles, the most controversial issue was the final volume to be dredged. There was an almost 12,000 cubic metre difference in rock, which represents a substantial financial impact and would render the entire project unfeasible for the dredging contractor, who would have to dredge more material at possibly higher cost due to the highly uncertain volume outcome caused by the lack of depth analysis and bottom interpretation because of the limited hydrographic surveying equipment.

Table 1 shows the estimated volume of material to be removed in the dredging project, according to the research team (using an

Figure 5: The relationship between the in situ image and the digital echogram record. By José Bartolomeu Ferreira Fontes, Mathias Schlosser and Lígia Maria Simon Falleiros Fontes, Brazil

Figure 5

echosounder without an echogram) and our supervision team (with digital echogram data). These numbers are crucial for determining how much funding is needed for the dredging company responsible for the detonation and removal of rocky material. The area, rock drilling time and line spacing between sections were the same. The contracting authority considered the volume to be dredged based on the bathymetric survey with echogram as the most reliable and consistent survey result, as it was possible to verify the true bottom line and characteristics by recording the digital echogram.

Multibeam surveys were performed at the end of each section to support final clearance procedures. For comparison purposes only, a volume calculation was carried out using both methodologies, and the difference fell within the project’s tolerance limits, reinforcing the reliability of both methods when used appropriately (see Figure 6). In conclusion, the echogram produced by the singlebeam echosounder plays a critical role in dredging operations, particularly when it comes to strategic decision-making. In the Tietê River project, determining whether remaining elements are part of the natural riverbed or not can mean the difference between operational success or failure. Such insights are essential to authorize the use of drilling and blasting equipment and to maintain the project’s economic viability.

Conclusion

It is important to achieve the best results not only by relying on expensive equipment and software algorithms but also by acknowledging the analysis of operators through their experience and local knowledge, as echogram data allows you to see below the water surface and even the bottom. The echogram, or better yet, the digital echogram, not only visualizes the invisible but also records evidence. It is useful during data post-processing, but also as evidence in discussion with the supervisor or contracting authority that may not agree with the survey result or volume but must agree after verifying the echogram record. Echogram data enables better interpretation of the true bottom, with the primary goal of avoiding erroneous depth data and volume results.

References

Fontes J. B. (2010). Deeping of the Port of Santos – Dredging to Results Multibeam x Single Beam. Hydro 2010 – Rostock –Warnemünde.

Hamilton, L.J. (2001). Acoustic Seabed Classification Systems. Defense Science & Technology Organization DSTO.

Lurton, Xavier (2002): An Introduction to Underwater Acoustics. Springer / Praxis.

Citation

Fontes, J.B., Schlosser, M., Fontes, L.F. (2025). “Vanguard Technology: The Crucial Importance of The Bathymetry Echogram for The Success of The Excavation Work.”

Proceedings of the World Dredging Congress & Exhibition WODCON XXIV ‘25, San Diego, CA, USA, June 23-27, 2025.

Table 1: Volume to be dredged.

Large-area shallow water and coastal zone mapping opportunities

Exploring the potential of fused imaging and Lidar data for seabed classification

By Anders Ekelund, vice president airborne bathymetric Lidar, Hexagon

The exploration and classification of the seabed have always been crucial for various scientific, environmental and commercial purposes. Traditional methods of seabed classification have relied heavily on sonar and direct sampling techniques. However, recent advancements have opened up new possibilities, particularly through the fusion of airborne imaging and bathymetric Lidar data. This article delves into the potential of these fused datasets for large-area shallow seabed classification.

Bathymetric Lidar (light detection and ranging) technology offers the ability to create precise 3D maps of the seabed, providing valuable data on its morphology. Additionally, the radiometric properties of both the water volume and the seabed are recorded in the Lidar wavelength (515nm). The Lidar laser pulses are typically emitted with a constant pulse energy from a constant altitude, ensuring that the radiometric response does not vary with sun angles, cloud shadows and atmospheric losses as it does with passive imaging. Furthermore, the shape of the received reflection can provide information on whether the emitted beam has been reflected off high vegetation or a flat seabed, for example. All this information can be used to aid a seabed classification algorithm.

Airborne imaging

Modern bathymetric Lidar systems also integrate airborne imaging in four bands: red, green, blue and near infrared (NIR delivering a resolution of typically 5cm). This passive imaging primarily aids in seabed classification, as different materials reflect different wavelengths. Unlike imaging over land, water significantly impacts the measured radiometry, which must be compensated for. The water surface can cause specular reflections from the sun (sunglint), affecting certain sections of the image. Additionally, the transmission varies

for different wavelengths: water is almost opaque for NIR, the red band provides information for only a few metres even in clear waters, and the blue and green bands

have significantly higher transmission. Creating useful radiometric seabed information from airborne imaging typically requires advanced image normalization

Airborne RGB image, co-collected with the bathy Lidar.

algorithms, including solar radiation and sun angle modelling, sunglint removal and compensation for water radiometric properties. The depth measured from Lidar plays a significant role in aiding these normalization algorithms.

Airborne hyperspectral imaging collects passive imaging with a lower spatial resolution but in many more and narrower bands than airborne imaging. The additional bands offer more accurate modelling of water properties and seabed radiometry. However, like airborne imaging, advanced algorithms are needed for data normalization for seabed classification use.

Fusing the datasets

The fusion of imaging and Lidar data combines the strengths of all technologies, resulting in a more comprehensive and accurate representation of the seabed. By integrating passive imaging radiometric data with precise 3D bathymetric information, we can gain deeper insights into the seabed’s characteristics. This fusion allows for the identification of subtle features that might be missed when using either technology alone.

Applications of fused data in seabed classification

1. Habitat mapping: Fused imaging and Lidar data can be used to create detailed habitat maps, identifying different types of seabed environments and the species that inhabit them. This information is crucial for marine conservation efforts and the management of marine protected areas. This can include additional factors such as seabed slope and roughness derived from the bathymetric

information and ‘health’ metrics such as chlorophyll presence and algal blooms from the hyperspectral data.

2. River exploration: Bathymetric Lidar is heavily used for river mapping, primarily for the purpose of flood modelling and mitigation. The radiometric information can however reveal important information, such as playgrounds for salmon habitats and the presence of run-off from adjacent land use.

3. Environmental monitoring: Fused data can be used to monitor changes in the seabed over time, as well as local pollution in the water, providing valuable information on the impacts of human activities such as trawling, dredging and sewage outlets and natural events such as storms and earthquakes.

4. Archaeological surveys: Underwater archaeology can also benefit from the fusion of imaging and Lidar data. Detailed maps of the seabed can reveal the locations of shipwrecks, submerged settlements and other archaeological sites, aiding in their preservation and study.

Comparison with other technologies

1. Sonar: Sonar technology is widely used, and significant advancements are taking place, particularly in utilizing sonar backscatter information for seabed classification. Compared to airborne capture, sonar covers much smaller areas and its efficiency decreases with decreased depth, whereas airborne capture

3D model from airborne topo/bathy Lidar.

Seabed classification based on fused airborne bathy Lidar and imaging data.

maintains constant efficiency. Many bathymetric Lidar survey providers also capture shipborne sonar data and fuse the datasets to optimize collection efficiency. It is important to note that sonar measures different properties compared to airborne data. While sonar measures the ‘hardness’ of the seabed, airborne data collects ‘radiometric’ properties.

2. ROVs and direct underwater sampling: Equipping ROVs (remotely operated vehicles) and/or towed underwater devices with cameras and sonar technology allows for data capture very close to the seabed with remarkable resolution. This high-resolution data enables detailed species recognition, classification and identification. The primary disadvantage compared to airborne capture is the limited area coverage. However, when used in combination with airborne capture, such datasets are ideal for creating training datasets for machine learning algorithms, enabling large-scale classification.

3. Satellite-based seabed classification: Satellite-captured multispectral data offers another method for seabed classification. Unlike airborne data, satellite remote sensing is heavily affected by atmospheric conditions, where small errors in atmospheric correction can lead to significant errors in the measured radiometric properties of the seabed. Additionally, cloud coverage can severely impact the capture of satellite images, making it challenging to find suitable images to be used, depending on the area of interest.

About the author

Anders Ekelund is vice president of airborne bathymetric Lidar at Hexagon’s Geosystems division, where he develops solutions and services for the bathymetric industry. With 20 years of experience in airborne technologies, he previously served as managing director of Airborne Hydrography AB (AHAB), acquired by Hexagon in 2013. Ekelund holds an MSc in Mechanical Engineering, specializing in automatic control theory, from Linköping University, Sweden.

Compared to airborne imaging, satellite resolution is much lower, and compared to airborne Lidar, depth penetration and accuracy are significantly less. However, combining airborne Lidar and satellite data can be an effective approach for scaling.

The potential of data fusion

Data fusion of multiple sensors offers large potential for enhanced seabed modelling. These technologies provide different resolutions, measure multiple properties and cover different parts of the seabed. By combining the strengths of multiple data sources, we can achieve a more complete, detailed and accurate understanding of the seabed’s characteristics. This has far-reaching implications for habitat mapping, resource exploration, environmental monitoring and underwater archaeology. As technology continues to advance, the possibilities for using fused data in seabed classification are bound to grow, paving the way for new discoveries and innovations in marine science.

Modern freshwater pipeline and remains from Bronze Age construction on the seabed. The Bronze Age construction is estimated at 3,300–3,500 years old, located at about four metres depth due to land mass elevation change.

Advancements in airborne topobathymetric Lidar and imaging

Airborne topobathymetric Lidar and imaging offer an unmatched combination of accuracy and resolution for nationwide coastal and inland water surveys in shallow waters. Recent developments have increased collection efficiency by up to 250% compared to previous generations, enabling not only one-off collections but also repetitive surveys needed to monitor changes over time in a cost-efficient manner. As about 40% of the world population lives in coastal zones, coastal nearshore information is highly valuable for maximizing the return on infrastructure investments, mitigating risks from coastal changes and preserving essential marine habitats. More and more countries understand the value of an updated national coastal elevation model and the market for airborne bathymetric Lidar is therefore likely to continue to grow.

Questions to... 5

Jamie McMichael-Phillips, Seabed 2030

What will it take to map the remaining 70% of our planet’s seafloor in just five years? That’s the challenge facing the Nippon FoundationGEBCO Seabed 2030 Project, a global initiative to deliver a complete map of the ocean floor by 2030. Director Jamie McMichael-Phillips is leading this unprecedented effort, bringing together new technologies, international partnerships and thousands of contributors worldwide. In this Q&A, he shares perspectives on recent progress, emerging innovations and the road ahead.

As of the June 2025 update, Seabed 2030 has mapped 27.3% of the ocean floor – adding around four million km² in just one year. What major logistical or technological shifts enabled this rapid progress, and do you see this pace accelerating further?

We have indeed had a successful year, thanks to the significant efforts of our

many, many contributors. Increasingly, existing bathymetric data is being discovered and made available, and more organizations are recognizing the importance of ocean mapping – often integrating it into their missions at sea.

We’ve seen a steady rise in the use of uncrewed and autonomous vessels, alongside more frequent application of satellite-derived bathymetry (SDB) in shallow and hard-to-reach areas. Advances in automated data processing, cloudbased workflows and, more recently, the emergence of AI are also contributing to this acceleration.

Crucially, all of this is underpinned by strengthened international collaboration in supporting Seabed 2030. Our contributor base continues to grow, with a remarkable number of organizations now supporting the effort. This is all part of our focus to inspire mapping of the ocean and to encourage open data sharing.

Recent research highlights that while shallow and bathyal zones have seen significant mapping increases, the abyssal plains – covering over 70% of the seafloor – still lag behind. How is Seabed 2030 prioritizing mapping in ultra-deep zones versus more accessible areas?

Our Seabed 2030 Regional Centers are always available to support ocean mappers in identifying priority areas and encouraging coordinated efforts to map them. Of course, we are heavily reliant on external contributors to carry out the mapping effort. By partnering with these organizations – particularly those that are experienced in deep-ocean exploration, we can work more closely with them to help focus efforts on the vast unmapped areas of our ocean. A good example of this is our recent Memorandum of Understanding with OceanQuest, which is actively advancing deep-sea discovery.

We continue to strengthen relationships with private-sector operators and organizations that have the capacity to reach and map these remote regions. By leveraging planned activities to address priority data gaps, we can make the most of every opportunity to extend global mapping coverage.

With 14 new organizations contributing – five from Africa and the Pacific –how is Seabed 2030 working to ensure equitable capacity building and data sovereignty, particularly within EEZs of developing nations?

Seabed 2030’s mission is to accelerate GEBCO’s original aim of providing the most authoritative bathymetric data and making it freely available. We do this by inspiring ocean mapping and compiling available bathymetry into the GEBCO Map.

We also recognize the importance of data sovereignty and work closely with national partners to ensure contributions are shared in ways that align with their priorities and policies. Our aim is to empower countries to map their own waters and make use of that data to support national development, marine management and scientific research. Within our limited resources, we’ve been able to deliver regional capacity-sharing workshops – working alongside regional experts and institutions to support the use of mapping tools and techniques.

We’re keen to continue encouraging national and regional mapping efforts, and it’s encouraging to see growing contributions from Africa and the Pacific. Together, these developments reflect growing global engagement and a more inclusive mapping community.

Seabed 2030 is a collaborative project between The Nippon Foundation and GEBCO to inspire the complete mapping of the world’s ocean by 2030, and to compile all bathymetric data into the freely available GEBCO Ocean Map. GEBCO is a joint project of the International Hydrographic Organization (IHO) and the Intergovernmental Oceanographic Commission (IOC) and is the only organization with a mandate to map the entire ocean floor. Seabed 2030 is formally endorsed as a Decade Action of the UN Decade of Ocean Science for Sustainable Development.

Many governments and private entities still hesitate to share detailed bathymetric data due to security, economic or strategic reasons. What concrete steps is Seabed 2030 taking to build trust and incentivize wider data sharing among these critical stakeholders?

There are many reasons why governments, institutions and privatesector stakeholders may hesitate to share detailed bathymetric data – often due to security, economic or commercial concerns. From a Seabed 2030 perspective, we are not seeking highresolution data. At best, we’re looking for one depth measurement within a 100m-by-100m grid cell – that’s a single sounding in an area broadly the size of a European football pitch.

By working with institutions and data holders to clarify that this coarse resolution does not compromise sensitive information, we can help facilitate the release of more data for integration into the GEBCO Map. Such contributions can also be seen as acts of leadership –supporting environmental stewardship, resilience, scientific progress and a deeper understanding of the ocean that benefits us all.

Given that current estimates suggest it could take nearly a millennium of ship

years to fully map all unmapped areas, are there groundbreaking technologies – such as AUV swarms, satellite bathymetry or autonomous fishing vessel sensors – that you believe could realistically allow Seabed 2030 to meet its 2030 goal?

More than 71% of our planet’s surface is covered by water, and to date we’ve mapped 27.3% of it – a significant milestone. But with nearly three quarters of the ocean still to go, achieving a fully mapped seafloor by 2030 depends not only on innovative new tools, but also on scaling up and combining technologies to add value.

SDB can help fill coastal and hard-toaccess areas. Uncrewed and autonomous platforms are increasingly complementing conventional survey vessels. And crowdsourced bathymetry – particularly from commercial and research vessels already at sea – holds enormous potential.

Together, these approaches can accelerate progress towards a complete map of the ocean floor. Seabed 2030 plays a vital role in coordinating these efforts – aligning partners, technologies and opportunities to maximize their collective impact. The result is more than just a map – it’s a critical foundation for understanding our climate, protecting ecosystems and supporting the sustainable management of the ocean.

HYDRO 3-2025

Something’s missing

Headlines

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Honouring Oman’s hydrographic journey

About Captain Ahmed Al Badi

How NOAA Coast Survey streamlines workflows for vital navigation products

Unlocking hydrographic data throughput

Modernized specifications

ArcGIS brings geographic dimension to big data

Effective data quality review

About the authors

A culture of streamlining

AI/ML boosts hydrographic data processing in SONARMUS

Sidescan sonar data processing

Single-beam echosounder data processing

Further reading

Conclusion

Follow Hydro International on LinkedIn

Ocean Aero uses NEPI for AI-enabled maritime inspection and monitoring

About Numurus

More information

Lidar + Sonar = a revolution in seafloor mapping

Opportunities to innovate

About the authors

Mapping the Antarctic continental slopes to understand shelf to abyss connectivity

A new catalogue of Antarctic submarine canyons

Acknowledgements

Impact on ocean circulation

About the authors

Conclusion

Investment in maritime digital future brings busy times for New Zealand hydrographers

Joint responsibility for safe navigation

Skilled professionals

Shaping safer seas

Soundscape around an offshore Dutch platform in the Dogger Bank

What goes bump in the night around an offshore platform?

Study methods

Results

Chrono-anthropogenic noise

About the authors

Significant advancement

EvoLogics Sonobot 5 USV: expanding capabilities

Origins

Technical capabilities

Use cases in practice

Looking ahead

Identifying true bottom for reliable dredging results

Bottom characterization methods

Dredging project

About the authors

Exploring the potential of fused imaging and Lidar data for seabed classification

Airborne imaging

Fusing the datasets

Applications of fused data in seabed classification

Comparison with other technologies

About the author

The potential of data fusion

Advancements in airborne topobathymetric Lidar and imaging

Questions to... 5

Jamie McMichael-Phillips, Seabed 2030