Presentations in the session will highlight acquisition, processing, and workflows for mapping of the coastal and nearshore environment with satellite derived bathymetry, aerial topobathymetric lidar, SAR, and other sensors.
11:00 AM – 11:15 AM – Coherent Topo-Bathy in One Pass – Revisiting Shipwrecks and Riverbends in the Great Lakes and Beyond: A Closer Look at Bathymetric Resolution and Geometric Coherence
Repeatable high‑resolution mapping of riverine environments and coastal margins requires airborne lidar systems that can capture coherent topography and bathymetry in a single pass, across varying flight geometries and water‑column conditions. We present and evaluate Fathom, an integrated topo‑bathy architecture that couples a 60 kHz bathymetric laser array (effective 240 kHz sounding rate) with a 1.5 MHz topographic channel through a unified calibration of both optical paths.
Test flights over riverbed and Georgian Bay (Ontario) at two survey altitudes demonstrate sub‑decimeter vertical coherence between strips, comprehensive water‑surface detection, and depth penetration consistent with Kd × Dmax ≈ 3.2. Relative to historic CZMIL SuperNova transects, Fathom’s narrower beam divergence and tighter swath—together with its denser point cloud—more confidently resolve navigation hazards such as shipwreck masts and reveal intricate river‑bed relief that raster smoothing previously obscured, illustrating gains in bathymetric resolution and repeat‑survey fidelity.
The presentation details the hardware layout, simultaneous geometric and radiometric calibration, multichannel waveform processing, shallow‑water signal deconvolution, and a surface‑slope‑adaptive refraction correction. Measured accuracies satisfy IHO S‑44 Order 1a bathymetry and USACE QL0B topography, indicating that a single‑flight, dual‑channel lidar can meet modern standards for hydrographic charting, infrastructure monitoring, and rapid response in inland and coastal settings.
Brandon Maingot, Teledyne Geospatial
11:15 AM – 11:30 AM – Advancing Shallow Water Bathymetry Through Laser and Hyperspectral Fusion
Mapping shallow aquatic environments with high fidelity remains a persistent challenge in geospatial science. This presentation introduces an integrated approach that combines airborne laser bathymetry (ALB) with hyperspectral imagery (HSI) to enhance accuracy, depth estimation, and bottom-type classification in coastal and freshwater systems.
By fusing ALB’s geometric precision with HSI’s rich spectral sensitivity, we demonstrate how this multi sensor technique resolves water column attenuation effects, improves substrate discrimination, and enables sub-meter bathymetric modeling in depths less than 10 meters. Using calibrated reflectance algorithms and novel fusion pipelines, benthic features such as sand, vegetation, and rock are distinguished with high confidence—even under turbid conditions.
Key components include:
- Spectral-band optimization for water transparency and bottom albedo
- Joint waveform analysis to correlate HSI reflectance with bathymetric returns
- Machine learning classifiers trained on fused spatial–spectral datasets
- Field validation using UAV-based systems over Icelandic fjords and tropical estuaries
- This multispectral synergy offers a transformative method for monitoring coastal erosion, submerged habitats, and sediment transport—especially in regions where traditional sonar and visual mapping are limited.
Steve du Plessis, ITRES Research Limited
11:30 AM – 11:45 AM – Comprehensive Seafloor Mapping of Florida’s Coastal Waters Using Topographic-Bathymetric Lidar and Multibeam Sonar Technology
The Florida Seafloor Mapping Initiative (FSMI), led by the Florida Department of Environmental Protection (FDEP), is a vital effort to enhance coastal monitoring through advanced mapping technologies. The Woolpert team used airborne topographic-bathymetric (topo-bathy) lidar and vessel-based sonar to achieve coverage from the shore to the continental shelf edge. This dataset provides a detailed understanding of Florida’s seafloor, benefiting environmental management and the Blue Economy.
The topographic-bathymetric (topo-bathy) lidar mapping efforts focused on FSMI’s Region 3, covering over 27,000 square kilometers off the southern coast of Florida, including the Florida Keys, Dry Tortugas, and parts of the Southeast Gulf of Mexico. The lidar technology employed mapped depths up to 50 meters.
Furthermore, the Woolpert team supported the FSMI with vessel-based multibeam sonar surveys to achieve comprehensive seafloor mapping by filling gaps in the topo-bathy coverage or extending coverage deeper than 50 meters. The sonar work covered nearly 18,000 square kilometers in areas within Regions 1 (Northeast FL), 5 (Big Bend), and 6 (Panhandle). This dual lidar/sonar approach ensured that the FSMI achieved a complete bathymetric understanding of Florida’s territorial waters, enhancing the accuracy and utility of the data for various applications such as habitat mapping, navigation safety, and resource management.
Karen Hart, Woolpert, Inc.
Dave Neff, Woolpert, Inc.
11:45 PM – 12:00 PM – Interagency Airborne Technologies for Lidar, Analysis, and Surveying: 2023 Hawaii Bathymetric Lidar Acquisition, Processing, and Applications
I-ATLAS, Interagency Airborne Technologies for Lidar, Analysis, and Surveying, formerly known as the Joint Airborne Lidar Bathymetry Technical Center of Expertise (JALBTCX), presents its acquisition and processing workflows for the 2023 National Coastal Mapping Program (NCMP) Hawaii collect which covers up to 500 meters of topographic and laser extinction of bathymetric data around the shoreline of the five major islands. The 2023 collection takes advantage of hardware and software improvements for both deeper and shallower data than the 2013 NCMP Hawaii visit. Additional noise filters to preserve features and reduce manual editing or editing mistakes will also be shared.
Several use cases from the U.S. Army Corps of Engineers Honolulu District and collaborating State, Federal, and University partners will be shared. Applications range from studies to protect historic fishponds, modelling to restore local boat access affected by the 2018 Big Island eruption, and data sources to understand the long-term socio-economic impacts from environmental and infrastructure changes.
Nicholas Johnson, USACE
12:00 PM – 12:15 PM – Integrated Analysis of USGS 3DEP Inland Bathymetric Airborne Lidar Campaigns
USGS performed many inland bathymetric airborne lidar in the last decade. The airborne lidar data collection campaigns were performed at Kootenai river, Chehalis river, McKenzie river, Niobrara river, Alleghany river, and Potomac river. The water quality ranges from turbid shallow water with lots of suspended solids to the clean deep water. The bathymetric lidar systems used are Riegl VQ-880G, Leica Chiroptera, Leica HawkEye, and CZMIL Nova. The beam divergence ranges from 0.5 mrad for a higher point density system for shallow water to 5 mrad for a lower point density system for deep water. Laser pulse energy ranges from 0.02 mJ for shallow water system to 3 mJ for deep water system. The scanner types are either circular or elliptical. All bathymetric lidar systems uses 532 nm wavelength laser. To increase the depth coverage, the airborne campaign was performed mostly in the dry season. Thus, most of the surveyed river were very shallow (less than a meter), and lesser area of shallow water (less than 5 meters), and small area of deep water. The depth coverage was analyzed using the las point classes provided by the data provider. The classes used are 40 (river bottom), 41(physical water surface), 42(synthetic water surface), 2(ground). Using the combination of these classes, it is possible to identify valid bathymetric lidar coverage and depth penetration. The validation of bathymetric lidar was performed using waded GNSS ground check points (GCPs) and Teledyne Z-boat single beam sonar GCPs. Z-boat data accuracy was also calibrated before using them as a reference for airborne bathymetric lidar accuracy. Also performed is the topo lidar accuracy using full 3D accuracy concept. Various 3D geometric features like multi-plane intercept, two-line crossing, plane to line crossing, and amorphous objects methods are used. In summary, we present the performance of bathymetric lidar performances over many rivers of varying optical properties using several different bathymetric lidar systems of varying specifications.
Minsu Kim, KBR / USGS
12:15 PM – 12:30 PM – UAS Bathymetric Lidar for River Surveys: An Accuracy Assessment on the Clackamas River, Oregon
UAS-based bathymetric lidar is an emerging technology for acquiring high-resolution bathymetry of rivers in localized areas. It can collect data in areas too shallow or dangerous for boats and potentially provide much higher spatial resolution than conventional bathymetric lidar from crewed aircraft. However, little is known about the accuracy and quality of these systems for river mapping and subsequent hydrodynamic modelling and grain size analysis. To address this, an Oregon State University team collected control and drone survey data on a reach of the Clackamas River in Oregon to conduct an accuracy assessment of a novel topo-bathymetric lidar system, the YellowScan Navigator. The UAS topo-bathymetric data were evaluated against concurrently collected, in-situ GNSS and total station-based control data. Then, the data were compared to other data sets, including multibeam echosounder (MBES) data collected from a small boat, airborne bathymetric lidar data collected from a conventional aircraft, UAS topographic lidar, and UAS photogrammetric data to quantify differences in spatial resolution, accuracy, and completeness. Our initial results suggest that the YellowScan Navigator can collect high-precision, accurate, and dense data suitable for localized river surveying and analysis in conditions supported by the system.
Baird Quinn, Oregon State University
