Bathymetry and Backscatter Intensity of the Sea Floor South of Long Island, New York

Surveys of the bathymetry and backscatter intensity of the sea floor south of Long Island, New York, were carried out in November 1998 using a Simrad EM1000 multibeam echosounder mounted on the Canadian Coast Guard ship Frederick G. Creed. The purpose of the multibeam echosounder surveys was to explore the bathymetry and backscatter intensity of the sea floor in several areas off the southern coast of Long Island along the 20-meter isobath. Survey areas offshore of Fire Island Inlet, Moriches Inlet, Shinnecock Inlet, and southwest of Montauk Point were about 1 kilometer (km) wide and 10 km long. The area was mapped by the U.S. Geological Survey with support from the Canadian Hydrographic Service and the University of New Brunswick.

For each area, there are five datasets: grid of sea-floor bathymetry, GeoTIFF image of shaded-relief bathymetry, GeoTIFF image of backscatter intensity, GeoTIFF image of shaded-relief bathymetry colored by backscatter intensity, and trackline navigation. The bathymetry shows the shape of the sea floor. Of particular interest are the size, shape, and orientation of bed forms that may indicate sediment movement. The shaded-relief image provides a visualization of the bathymetry that accentuates small features that cannot be effectively shown as contours alone. The image of backscatter intensity provides qualitative information on the sediment texture and roughness of the sea floor. The image of shaded-relief bathymetry, colored by backscatter intensity, provides a visualization of both the bathymetry and backscatter intensity. The navigation tracklines show how the survey was carried out and allow identification of data collected directly beneath the ship.

NOTE: These data were originally published in USGS ScienceBase in 2016, grouped by survey area in four sub-directories that contained links to the five datasets for each area. In 2026, the structure of ScienceBase was revised, and the datasets are now all listed alphabetically by title on a single page rather than organized by area. As a result of the file-naming convention, datasets of the same type appear consecutively in the list.