Operational TPU Software for Topobathymetric Lidar

TitleOperational TPU Software for Topobathymetric Lidar
Publication TypeConference Proceedings
AuthorsParrish, CE, Eren, F, Jung, J, Forfinski, N, Calder, BR, White, SA, Imahori, G, Kum, J, Aslaksen, M
Conference Name19th Annual JALBTCX Airborne Coastal Mapping and Charting Workshop
Conference DatesJune 26-28
Conference LocationProvidence, RI

While topobathymetric lidar has been established as an effective technology for updating shoreline on nautical charts, there is great interest in the ability to simultaneously use the data to update charted depths (or “soundings”) in areas in areas too shallow for boats to operate safely or efficiently. However, operational use of topobathymetric lidar data in nautical charting programs requires total propagated uncertainty (TPU) models and tools comparable to those that exist for hydrographic surveys conducted with multibeam echosounders. The TPU requirement is based on the International Hydrographic Organization (IHO) “Standards for Hydrographic Surveys” (S-44), as well as surface generation algorithms that rely on the availability of per-point uncertainty estimates. A comprehensive TPU model has been developed for the Riegl VQ-880-G operated by NOAA’s National Geodetic Survey (NGS). The model combines analytical uncertainty propagation for the subaerial (above water) portion and Monte Carlo simulation models for the subaqueous portion (water surface to seafloor). Because a key goal of the project is to support routine, operational use of the TPU software, computation time and ease-of-use have been important considerations in the development. The TPU model has been implemented in Python software, which is currently being tested on multiple data sets by NGS. Next steps in the project will include extending the methods to other bathymetric lidar systems.