Shot point navigation at even 500 shot intervals for EdgeTech SB-512i and SB-424 chirp seismic-reflection data collected by the U.S. Geological Survey offshore of Massachusetts between Duxbury and Hull (DH_SeismicShot_500 shapefile, Geographic, WGS84)

These data were collected under a cooperative agreement with the Massachusetts Office of Coastal Zone Management (CZM) and the U.S. Geological Survey (USGS), Coastal and Marine Geology Program, Woods Hole Science Center (WHSC). Initiated in 2003, the primary objective of this program is to develop regional geologic framework information for the management of coastal and marine resources. Accurate data and maps of sea-floor geology are important first steps toward protecting fish habitat, delineating marine resources, and assessing environmental changes due to natural or human impacts. The project is focused on the inshore waters (5-30 m deep) of Massachusetts between the New Hampshire border and Cape Cod Bay. Data collected for the mapping cooperative have been released in a series of USGS Open-File Reports (http://woodshole.er.usgs.gov/project-pages/coastal_mass/html/current_map.html). This spatial dataset is from the study area located between Duxbury and Hull Massachusetts, and consists of high-resolution geophysics (bathymetry, backscatter intensity, and seismic reflection) and ground validation (sediment samples, video tracklines and bottom photographs). The data were collected during four separate surveys conducted between 2003 and 2007 (NOAA survey H10993 in 2003, USGS-WHSC survey 06012 in 2006, and USGS-WHSC surveys 07001 and 07003 in 2007) and cover more than 200 square kilometers of the inner continental shelf.