Page C. Valentine Jessica L. Baker Tanya S. Unger 2005 1.0 remote-sensing image Scientific Investigations Map2840 Woods Hole Science Center, Woods Hole, MA U.S. Geological Survey, Coastal and Marine Geology Program http://pubs.usgs.gov/sim/2005/2840/data/backscatter/bcksctter.zip Page C. Valentine, editor 2005 1.0 Scientific Investigations Map 2840 Woods Hole Science Center, Woods Hole, MA U.S. Geological Survey, Coastal and Marine Geology Program 1:60,000, 6 maps, 12 sheets http://pubs.usgs.gov/sim/2005/2840/ bcksctter.tif This data set contains the sun-illuminated topographic imagery and backscatter intensity generated from a multibeam sonar survey of the Stellwagen Bank National Marine Sanctuary region off Boston, Massachusetts, an area of approximately 1100 square nautical miles. The Stellwagen Bank NMS Mapping Project is designed to provide detailed maps of the Stellwagen Bank region's environments and habitats and the first complete multibeam topographic and sea floor characterization maps of a significant region of the shallow EEZ. Data were collected on four cruises over a two year period from the fall of 1994 to the fall of 1996. The surveys were conducted aboard the Canadian Hydrographic Service vessel Frederick G. Creed, a SWATH (Small Waterplane Twin Hull) ship that surveys at speeds of up to 16 knots. The multibeam data were collected utilizing a Simrad Subsea EM 1000 Multibeam Echo Sounder (95 kHz) that is permanently installed in the hull of the Creed. Development of interpretive seabed maps, sea floor imagery, and a GIS database that are accessible to scientists, policymakers, managers, and the general public. en 1994 1998 ground condition Complete As needed -70.600 -70.0333 42.800 42.0833 -23590.86523423612.1347663850010.4985743930597.498574 General Geographic Information Systems U.S. Geological Survey USGS Coastal and Marine Geology Program CMGP Woods Hole Science Center WHSC SIMRAD SUBSEA EM 1000 Frederick G. Creed Multibeam Echo Sounder Sea floor topography bathymetry shaded relief imagery backscatter intensity psuedo color encoded GeoTIFF image General Massachusetts MA Stellwagen Bank National Marine Sanctuary SBNMS Shallow EEZ EEZ Gulf of Maine Atlantic Ocean North Atlantic Boston oceans and estuariesgeoscientificInformationISO 19115 Topic CategoryimageryBaseMapsEarthCoverelevation None Public domain data from the U.S. Government are freely redistributable with proper metadata and source attribution. Please recognize the U.S. Geological Survey (USGS) as the source of this information. Page C. Valentine U.S. Geological Survey Research Geologist mailing and physical address

U.S. Geological Survey

384 Woods Hole Rd.

Woods Hole MA 02543-1598 USA (508) 548-8700 x2239 (508) 457-2310 pvalentine@usgs.gov Page C. Valentine Tammie J. Middleton Sarah J. Fuller 2001 1.01 Open-File Report 00-410 http://pubs.usgs.gov/of/of00-410/ Woods Hole Science Center, Woods Hole, MAU.S. Geological Survey, Coastal and Marine Geology Program Page C. Valentine Jessica L. Baker Tanya S. Unger 2003 1.0 map Geologic Investigations Map I-2676-C Woods Hole Science Center, Woods Hole, MAU.S. Geological Survey, Coastal and Marine Geology Program Microsoft Windows XP Version 5.1 (Build 2600) Service Pack 2; ESRI ArcCatalog 9.0.0.535Raster Datasethttp://pubs.usgs.gov/sim/2005/2840/data/backscatter/bcksctter-thumb.gifThumbnail image showing backscatter intensity and sun-illuminated topography of the seafloor in Stellwagen Bank National Marine Sanctuary region.GIFBrowse image showing backscatter intensity and sun-illuminated topography of the seafloor in Stellwagen Bank National Marine Sanctuary region.GIFhttp://pubs.usgs.gov/sim/2005/2840/data/backscatter/bcksctter-browse.gif The ship's position was determined with an accuracy of 10 m or better using a Magnavox 4200 geographic positioning system (GPS) receiver in conjunction with differential GPS corrections transmitted by U.S. Coast Guard radio beacons. At the start of each day, casts were made to record the sound velocity profile of the water column in the area to be surveyed. This information is used by the data acquisition system to correct for the refraction of the transmitted multibeam sound signal as it travels through the water to and from the sea floor. Multibeam echo sounder data was collected aboard the Canadian Hydrographic Service vessel Frederick G. Creed, an aluminum SWATH (Small Waterplane Area Twin Hull) ship that surveys at speeds up to 16 knots. The ship has two submerged torpedo-shaped hulls that support the main deck via two thin struts. This design reduces wave motion on the ship and resistance to the ship's forward motion through the water, thus making it a very stable platform at high survey speeds. Stability of the ship is also enhanced by the computer-controlled action of four stabilizer fins located fore and aft on the inboard side of the hulls. The stabilizers control the pitch and roll of the vessel and allow adjustment of the heel and trim of the ship while under way. An Applied Analytics POS/MV motion sensor located in the hull near the EM 1000 transducer detects changes in pitch, roll, and heave of the vessel. The motion information is recorded concurrently with the acquired multibeam signal and both are logged in a single file on the Sun workstation and made available to other workstations for further processing. The sidescan-sonar backscatter data are displayed in real time on the Sun workstation using software designed and written by the Ocean Mapping Group, University of New Brunswick. This display allows data gaps to be identified during the survey and also gives a measure of the data quality. Sounding rates depend on water depth but vary from 2 to 4 per second in water depths less than 100 meters. Horizontal spatial resolution at these sounding rates is on the order of 10% of the water depth at 16 knots; however, vertical resolution is approximately 1% or better in the same depth range. Sounding rates depend on water depth but vary from 2 to 4 per second in water depths less than 100 meters. Horizontal spatial resolution at these sounding rates is on the order of 10% of the water depth at 16 knots; however, vertical resolution is approximately 1% or better in the same depth range. Multibeam data were processed using SwathEd, a suite of multibeam software editing and display tools developed by Dr. John Hughes Clarke of the Ocean Mapping Group, University of New Brunswick (UNB). 13511700 Raster Pixel 6199 3631 1 13.00000013.0000008Upper LeftFALSENone3pixel codesTRUETIFFmetersmetersGeoTIFF Mercator 41.650000 -70.316667 0 0 row and column 13.000000 13.000000 meters North American Datum of 1983 Geodetic Reference System 80 Backscatter imagery combines the sun-illuminated topography with the backscatter intensity (shown here in color) of the sea floor. Backscatter intensity is a measure of the hardness and roughness of the sea floor as determined from the strength of sound waves reflected from the seabed during the survey. High-backscatter materials (red and orange) are coarse sand, gravel (including piles and ridges of boulders), and rock outcrops. Moderate backscatter (green) represents sand or muddy sand. Low backscatter (blue) represents sandy mud and mud. These interpretations apply best in region's of low regional topography, because steep slopes can divert the paths of some of the reflected sound waves away from the survey vessel. Thus, seabed that slopes steeply away from the survey track can produce a lower backscatter intensity than if it were level. Unnatural-looking stripes and patterns oriented parallel or perpendicular to survey track lines are artifacts of data collection. Blank areas represent places where no data exists. Page C. Valentine U.S. Geological Survey Research Geologist mailing and physical address

U.S. Geological Survey

384 Woods Hole Rd.

Woods Hole MA 02543-1598 USA (508) 548-8700 x2239 (508) 457-2310 pvalentine@usgs.gov Downloadable Data Although these data have been used by the U.S. Geological Survey, U.S. Department of the Interior, no warranty expressed or implied is made by the U.S. Geological Survey as to the accuracy of the data. Any use of trade, product, or firm names is for descriptive purposes only and does not imply endorsement by the U.S. Government. TIFF 0.000 0.000GeoTIFFA zip archive containing the GeoTIFF image, associated world file, and metadata.zip DVD-ROM UDF 4.75Gbytes http://pubs.usgs.gov/sim/2005/2840/data/backscatter/bcksctter.zip None This image is available as a GEOTIFF image with an accompanying world file. To utilize this data, the user must have an image viewer, image processing or GIS software package capable of importing a GeoTIFF image. 20050822 U.S. Geological Survey Page C. Valentine Research Geologist mailing and physical address

U.S. Geological Survey

384 Woods Hole Rd.

Woods Hole MA 02543-1598 USA (508) 548-8700 x2239 (508) 457-2310 pvalentine@usgs.gov FGDC Content Standards for Digital Geospatial Metadata FGDC-STD-001-1998 local time enNoneNone20050822http://www.esri.com/metadata/esriprof80.htmlESRI Metadata Profile 20050822 16505600 {397A4336-F24E-473B-9ECF-E407CE818351}2005080811553300FALSE2005082216505600 20050822 Microsoft Windows XP Version 5.1 (Build 2600) Service Pack 2; ESRI ArcCatalog 9.0.0.535bcksctter.tif-23590.86523423612.1347663930597.4985743850010.4985741ISO 19115 Geographic Information - MetadataDIS_ESRI1.0dataset002file://\\Erihefdtxp\G_DATA\SBNMSI-maps\dataforCD_081505\backscatter\bcksctter.tifLocal Area Network0.000Raster Dataset21363113unknown619913unknown