Beyond The Surface: How Laser Technology Revolutionized Marine Mapping

By John Oncea, Editor

From George Hickman's 1968 pioneering flight to NASA's space-based systems, bathymetric LiDAR has revolutionized underwater mapping and marine exploration.

The story of LiDAR, according to Todd Neff, starts in 1917 with Einstein’s proposal of stimulated emission, then advances in fits and starts through the 1950s. The 1960s witnessed an explosion of growth, from Theodore Maiman's demonstration of the first laser to the U.S. Navy’s test of its Pulsed Light Airborne Depth Sounder (PLADS) from a helicopter.

Each ensuing decade brought with it more growth and discovery. LiDAR in space, aboard Apollo 15 in 1971; the first laser-based police speed gun in the late 1980s; LiDAR flights discovering the Seattle Fault in 1996; LiDAR enabling a remote-control helicopter to guide itself and avoid trees, wires, and buildings in 2006; the European Space Agency’s launch of Aeolus, fitted with ultraviolet Doppler LiDAR to aid in its mission of measuring global winds 2018 … the list goes on.

In fact, I counted nearly 100 milestones on Neff’s list, each of which could make for an interesting story. But the one that caught my attention – mostly because of its unusual name – was the first bathymetric LiDAR flight by George Hickman in 1968.

The Birth Of An Underwater Revolution

The ability to peer through water and accurately measure depths from the sky represents one of the most ingenious applications of laser technology in modern surveying. Bathymetric LiDAR, which uses green laser light to penetrate water surfaces and map underwater terrain, has revolutionized how we understand and interact with our aquatic environments, from shallow coastal waters to inland rivers and lakes.

The story of bathymetric LiDAR begins just eight years after the invention of the laser itself. In 1968, George Hickman made aviation history by conducting the first bathymetric LiDAR flight over Lake Ontario. This pioneering mission marked the beginning of a technology that would eventually transform coastal mapping, marine archaeology, and environmental monitoring worldwide.

The early years of laser hydrography, as it was initially called, emerged from military applications focused on submarine detection. Throughout the 1960s and 1970s, extensive theoretical studies and system modeling efforts were conducted by the Naval Air Development Center (NADC), supporting anti-submarine programs that would inadvertently lay the groundwork for civilian bathymetric applications. These foundational efforts, coupled with ongoing field experiments at institutions like Scripps, provided critical performance predictions for airborne laser bathymeter systems, according to NOAA.

The technology gained momentum through the 1970s and 1980s with the development of second-generation experimental systems. Notable among these was the Airborne Oceanographic Lidar (AOL), a joint effort between NASA, NOAA, the U.S. Navy, and AVCO. By the mid-1980s, Optech's LARSEN 500 became the first operational lidar bathymeter, creating the first airborne-lidar-derived hydrographic chart of Cambridge Bay in the Canadian Arctic. The real breakthrough, according to Defense Technical Information Center (DTIC), came in 1993 with the introduction of the Scanning Hydrographic Operational Airborne Lidar Survey (SHOALS), which revolutionized coastal mapping capabilities.

Scientific Breakthroughs Beneath The Waves

Bathymetric LiDAR has enabled discoveries that were previously impossible or prohibitively expensive to achieve. One of the most significant contributions has been to underwater archaeology, where the technology has revealed submerged archaeological sites, including ancient shipwrecks and settlements. Using semi-automated analysis protocols, researchers have successfully identified previously undocumented archaeological sites in shallow water environments, demonstrating the technology's ability to detect subtle features on the seafloor that might indicate human habitation from periods when sea levels were lower, according to the Olo Be Taloha Lab.

The technology also has proven invaluable for marine habitat mapping and environmental conservation efforts. Bathymetric LiDAR enables accurate benthic habitat mapping, providing essential data for managing and protecting marine environments. According to Holland Productions, studies in regions like the Great Lakes have used this technology to gather detailed data on submerged aquatic vegetation and substrate types in nearshore environments, supporting ecological preservation efforts and habitat restoration projects.

In coastal management, bathymetric LiDAR has transformed our understanding of coastal erosion dynamics. The technology effectively maps both underwater and surrounding land areas simultaneously, providing comprehensive datasets crucial for monitoring coastal changes and developing preservation strategies. This capability has proven particularly valuable in areas affected by storms and climate change, where rapid environmental changes demand frequent, accurate monitoring.

Current Applications: A Technology In Full Bloom

Today's bathymetric LiDAR systems operate with remarkable sophistication, typically using frequency-doubled Nd:YAG lasers at 532 nm wavelength, chosen specifically because this green light experiences minimal absorption and scattering in clear water. Modern systems can achieve depths up to 50-70 meters in clear waters, with some advanced systems reaching even greater depths under optimal conditions, according to Hydro International.

The maritime industry relies heavily on bathymetric LiDAR for navigation safety and port management. According to NOAA, the technology provides critical data for maintaining shipping channels, monitoring harbor conditions, and ensuring safe passage in shallow waters where traditional ship-based surveys cannot operate effectively. Recent USACE FEMA surveys following Hurricane Milton in Florida demonstrate the technology's rapid response capabilities for post-disaster assessment and navigation safety restoration.

Environmental monitoring represents another major application area. The technology supports coastal zone management through detailed seabed topography mapping, essential for understanding coastal erosion dynamics and planning preservation strategies. Marine biologists use bathymetric LiDAR for comprehensive habitat mapping, studying coral reefs, seagrass beds, and other critical marine ecosystems that require precise spatial data for effective conservation.

Infrastructure development increasingly depends on bathymetric LiDAR data, according to MarketsandMarkets. Offshore wind farm development, underwater pipeline installation, and coastal engineering projects all require detailed seafloor maps that this technology provides efficiently and accurately. The growing offshore renewable energy sector particularly benefits from the technology's ability to rapidly survey large areas while providing the high-resolution data necessary for foundation design and environmental impact assessments.

Recent technological advances have expanded the technology's accessibility through UAV-mounted systems, according to Unmanned Systems Technology. These lightweight alternatives enable cost-effective surveys of smaller, localized areas that would be impractical for traditional aircraft-based systems. The development of UAV-compatible bathymetric LiDAR sensors represents a significant democratization of the technology, making it available for smaller-scale research projects and local environmental monitoring efforts, according to Hydro International.

The Future Horizon: Innovation And Integration

The future of bathymetric LiDAR appears remarkably bright, driven by several converging technological trends. Perhaps the most revolutionary development, according to ICESat-2, is NASA's ICESat-2 mission, which has demonstrated space-based bathymetric capabilities using photon-counting LiDAR technology. The new ATL24 data product provides bathymetric measurements from approximately 0.5 to 21.5 meters in depth across 13.7 million kilometers of coastal waters globally, offering unprecedented coverage for scientific research and navigation applications, according to Eos.

Artificial intelligence integration represents another transformative frontier. AI-powered algorithms are revolutionizing data processing efficiency by enabling rapid analysis of vast datasets, reducing manual intervention requirements, and minimizing human error. According to Precedence Research, machine learning models increasingly classify seabed features, detect anomalies, and identify marine species automatically, dramatically accelerating research outcomes and expanding the technology's analytical capabilities.

Autonomous underwater vehicles (AUVs) equipped with bathymetric LiDAR systems promise to extend mapping capabilities into previously inaccessible areas. These systems can operate independently for extended periods, collecting high-resolution data in challenging environments without requiring constant human supervision or expensive support vessels.

The miniaturization trend continues with next-generation sensors becoming lighter, more compact, and more power-efficient. This evolution enables deployment on smaller platforms, including advanced UAVs and potentially even smaller autonomous systems, dramatically reducing operational costs while increasing survey flexibility.

Enhanced automation in data processing workflows promises faster delivery of actionable results. Current developments focus on streamlining the path from raw data collection to final products, reducing the technical expertise required for system operation, and making the technology more accessible to a broader range of users.

Looking further ahead, integration with other remote sensing technologies will create comprehensive multi-sensor platforms. The combination of bathymetric LiDAR with hyperspectral imaging, advanced sonar systems, and satellite-derived bathymetry will provide unprecedented insights into underwater environments. These integrated systems will enable real-time environmental monitoring, supporting everything from climate change research to disaster response and marine conservation efforts.

The convergence of these technological advances positions bathymetric LiDAR as an increasingly essential tool for understanding and managing our planet's aquatic resources. As water security, coastal resilience, and marine ecosystem health become ever more critical to global sustainability, this technology will undoubtedly play a central role in addressing the challenges of the 21st century and beyond.