Parrish, C.E.; Dijkstra, J.A.; O'Neil-Dunne, J.P.M; McKenna, L., and Pe'eri, S., 2016. Post-Sandy benthic habitat mapping using new topobathymetric lidar technology and object-based image classification. In: Brock, J.C.; Gesch, D.B.; Parrish, C.E.; Rogers, J.N., and Wright, C.W. (eds.), Advances in Topobathymetric Mapping, Models, and Applications. Journal of Coastal Research, Special Issue, No. 76, pp. 200–208. Coconut Creek (Florida), ISSN 0749-0208.

Hurricane Sandy, which made landfall on the U.S. East Coast as a post-tropical cyclone on October 29, 2012, is the second costliest hurricane in U.S. history, behind Hurricane Katrina in 2005. In the wake of the storm, federal mapping agencies, including NOAA, USGS, and USACE, undertook extensive mapping efforts in the affected areas, including acquisition of aerial imagery, lidar (light detection and ranging), and other forms of remotely sensed data. Among the notable datasets acquired in the Sandy-impact region were those collected with new topobathymetric lidar systems, which feature markedly different designs than conventional bathymetric lidar technology. These systems are characterized by green-only laser beams, narrow fields-of-view (FOVs), and narrow beam divergence. The objective of this study was to investigate the ability to use data from a commercial topobathymetric lidar sysem, the Riegl VQ-820-G, operated by NOAA's National Geodetic Survey, for benthic habitat mapping—in particular, mapping of seagrass habitat in Barnegat Bay, New Jersey. Specific goals were 1) to assess the utility of the VQ-820-G reflectance and pulse deviation data, with minimal additional calibration or post-processing, in benthic habitat mapping; 2) to investigate the use of object-based image analysis (OBIA) in generating benthic habitat maps from the VQ-820-G data; and 3) to develop procedures that are currently being used in follow-on studies to investigate and quantify the ecological impacts of Sandy. Habitat maps were created in the OBIA system from the VQ-820-G data and simultaneously acquired imagery. A classification accuracy assessment was then performed through comparison against reference data acquired by the project team. Results indicate strong potential for benthic habitat mapping using the VQ-820-G waveform features, bathymetry, and ancillary datasets in an OBIA procedure. The project team is currently extending these procedures to data from the USGS EAARL-B lidar system to enable enhanced assessment of habitat change resulting from Sandy in the Barnegat Bay estuary.