U.S. Geological Survey 2006 1.0 remote-sensing image Open-File Report 2005-1048 Woods Hole Coastal and Marine Science Center, Woods Hole, MA U.S. Geological Survey, Coastal and Marine Geology Program https://doi.org/10.3133/ofr20051048 http://pubs.usgs.gov/of/2005/1048/data/backscatter/mosaic/geo/capenorthmos_geo4m_wgs84.zip http://pubs.usgs.gov/of/2005/1048/data/backscatter/mosaic/geo/capenorthmos_geo4m_wgs84.tif http://pubs.usgs.gov/of/2005/1048/htmldocs/data_catalog.htm http://pubs.usgs.gov/of/2005/1048/data/backscatter/mosaic/geo/ L.J. Poppe V.F. Paskevich B. Butman P.C. Valentine W.W. Danforth D.S. Foster D.S. Blackwood 2005 1.0 Open-File Report 2005-1048 Reston, VA U.S. Geological Survey http://pubs.usgs.gov/of/2005/1048/ This data set includes backscatter intensity of the sea floor offshore of northern Cape Cod, Massachusetts. The data were collected with a multibeam sea floor mapping system during USGS survey 98015, conducted November 9 - 25, 1998. The surveys were conducted using a Simrad EM 1000 multibeam echo sounder mounted aboard the Canadian Coast Guard vessel Frederick G. Creed. This multibeam system utilizes 60 electronically aimed receive beams spaced at intervals of 2.5 degrees that insonify a strip of sea floor up to 7.5 times the water depth (swath width of 100 to 200 m within the survey area). The horizontal resolution of the beam on the sea floor is approximately 10% of the water depth. Vertical resolution is approximately 1 percent of the water depth. With backscatter intensity, the intensity of the acoustic return from the sea floor from the multibeam system, is a function of the properties of the surficial sediments and of the bottom roughness. Generally, a strong return (light gray tones) is associated with rock or coarse-grained sediment, and a weak return (dark gray tones) with fine-grained sediments. However, the micro-topography, such as ripples, burrows, and benthic populations also affect the reflectivity of the sea floor. Direct observations, using bottom photography or video, and surface samples, are needed to verify interpretations of the backscatter intensity data. The backscatter data have a weak striping that runs parallel to the ship's track. Some of the striping is the result of poor data return at nadir that appears as evenly-spaced thin speckled lines. Some striping is also due to critical angle effects, where the intensity of return varies as a function of the angle of incidence of the incoming sound on the seafloor (Hughes-Clark and others, 1997). To release a digital map derived from multibeam observations that shows sea floor backscatter intensity (a measure of sea floor texture and roughness) at a spatial resolution of 4 meters per pixel. 19981109 19981125 ground condition Complete None planned -70.307833 -69.828333 42.116667 41.966667 USGS Metadata Identifier USGS:4a64325a-87ec-4b94-8373-41c705e95273 None U.S. Geological Survey USGS Woods Hole Science Center WHSC Coastal and Marine Geology Program CMGP Frederick G. Creed Field Activity Number 98015 Sea Floor Mapping Multibeam Echo Sounder Backscatter Intensity multibeam backscatter mosaic GeoTIFF Image greyscale image gray scale image Geographic Information System Sea Floor Geology Surficial Geology GeoTIFF Image Multibeam Simrad EM1000 ISO 19115 Topic Category oceans imageryBaseMapsEarthCover geoscientificInformation USGS Thesaurus sea-floor acoustic reflectivity image mosaics multibeam sonar marine geophysics geospatial datasets None Cape Cod Massachusetts Cape Cod National Seashore Park U.S. East Coast United States North America Atlantic Ocean None Public domain data are freely redistributable with proper metadata and source attribution. Please recognize the U.S. Geological Survey (USGS) as the source of this information. Lawrence J. Poppe U.S. Geological Survey Geologist mailing and physical address

384 Woods Hole Road

Woods Hole MA 02543-1598 USA (508) 548-8700 x2314 (508) 457-2310 lpoppe@usgs.gov http://pubs.usgs.gov/of/2005/1048/data/backscatter/mosaic/geo/capenorthmos_geo4m_wgs84-thumb.gif Thumbnail image showing the extent and coverage of the data layer. GIF http://pubs.usgs.gov/of/2005/1048/data/backscatter/mosaic/geo/capenorthmos_geo4m_wgs84.gif Image map showing the extent and coverage of the data layer. GIF Microsoft Windows XP Version 5.1 (Build 2600) Service Pack 2; ESRI ArcCatalog 9.1.0.722 Information unavailable from original metadata. This image is complete; all available data were used to create the backscatter mosaic; no further processing and(or) modifications will be made. These data were navigated with a Differential Global Positioning System (DGPS); they are accurate to +/- 3 meters, horizontally. USGS unpublished material This file had a source contribution, but no source citation information. This information was populated based on information in the source contribution. DVD-ROM 19981109 19981125 ground condition 98015_multibeam_data The original multibeam backscatter data acquired with a Simrad EM 1000 echosounder during USGS cruise 98015 aboard the Canadian Coast Guard vessel Frederick G. Creed Initial Data and acquisition processing at sea: After the echo sounder data were logged onto the hard disk of the Sun workstation, a suite of processing software developed by the Ocean Mapping Group (www.omg.unb.ca/~jhc/SwathEd.html) was used to correct for artifacts and errors that may have been introduced during data collection. This software also enhanced the corrected data by resolving beam pattern and aspect ratio distortions and by imposing a linear contrast stretch before it generated bathymetric and sidescan sonar image mosaics in a Mercator projection. All data processing described here is initiated using Silicon Graphics workstations as soon as each acquisition file is closed by the Simrad Mermaid workstation (usually at the end of each survey line). Additional processing was done in the lab to correct for fluctuations in sea level during the survey and for artifacts in the data files that were not corrected in the field (see below). The processing and editing steps on board the ship were: (A.) Demultiplex, or unravel, the acquired Simrad data files using RT to generate separate files containing navigation, depth soundings, sidescan sonar backscatter values, and sound velocity information. (B.) Automatically reject bad data (autoRejectSoundings). For the multibeam soundings, reject data outside expected depth ranges (operator's decision based on nautical chart data); for navigation data, reject fixes with poor GPS statistics. (C.) Edit the navigation data on-screen using jview to remove undesirable points, including turns at the ends of survey lines. (D.) Edit the multibeam soundings on-screen using swathed to remove individual anomalous soundings. (E). Merge tidal information and the corrected navigation back (mergetide and mergenav) into the data files. Tidal information was obtained from predicted tides using the Xtide program http://www.flaterco.com/xtide/xtide.html), which generated predicted tides based on the harmonic coefficients for Chatham provided by the Xtide program. (F.) Map the bathymetric soundings from each processed data file onto a Mercator grid using weigh_grid with node spacings and scale selected by the operator. The data files capenorth.asc and capenorth.xyz were produced from the gridded data. The data file capenorth.txt is a comma-delimited version of capenorth.xyz. (G.) Map the extracted sidescan sonar backscatter values onto a digital mosaic using mos2 in the Mercator projection at a scale selected by the user. 98015_multibeam_data Unknown capenorth.asc capenoth.xyz capenorth.txt capenorthmos_mer4m.tif Bill Danforth U.S. Geological Survey Geologist mailing and physical address

384 Woods Hole Road

Woods Hole MA 02543-1598 USA (508) 548-8700 x2274 (508) 457-2310 bdanforth@usgs.gov Map the extracted sidescan sonar backscatter values onto a digital mosaic using the SwathEd utility mos2 in the Mercator projection, having a central longitude of -70.3166667 degrees West, a latitude of true scale of 41.65 degrees north and the horizontal datum is WGS84. capenorth.asc capenorth.xyz capenorth.txt Unknown capenorthmos_mer4m.tif Bill Danforth U.S. Geological Survey Geologist mailing and physical address

384 Woods Hole Road

Woods Hole MA 02543-1598 USA (508) 548-8700 x2274 (508) 457-2310 bdanforth@usgs.gov The imagery in Mercator projection was converted to geographic. capenorthmos_mer4m.tif 2004 capenorthmos_mer4m_wgs84.tif Valerie Paskevich U.S. Geological Survey Information Technology Specialist / GIS Coordinator mailing and physical address

384 Woods Hole Road

Woods Hole MA 02543-1598 USA (508) 548-8700 x2281 (508) 457-2310 vpaskevich@usgs.gov Edits to the metadata were made to fix any errors that MP v 2.9.30 flagged. This is necessary to enable the metadata to be successfully harvested for various data catalogs. In some cases, this meant adding text "Information unavailable" or "Information unavailable from original metadata" for those required fields that were left blank. Most issues were with blank elements that could actually be removed. This file had a source contribution, but no source citation information. This information was populated based on information in the source contribution. Also, both geographic and planar coordinate systems, a common problem when using ArcCatalog. Other minor edits were probably performed (title, publisher, publication place, etc.). The metadata date (but not the metadata creator) was edited to reflect the date of these changes. The metadata available from a harvester may supersede metadata bundled within a download file. Compare the metadata dates to determine which metadata file is most recent. 20151109 U.S. Geological Survey VeeAnn A. Cross Marine Geologist mailing and physical address

384 Woods Hole Rd.

Woods Hole MA 02543 508-548-8700 x2251 508-457-2310 vatnipp@usgs.gov USGS Thesaurus keywords added to the keyword section. 20180720 U.S. Geological Survey VeeAnn A. Cross Marine Geologist Mailing and Physical

384 Woods Hole Road

Woods Hole MA 02543-1598 508-548-8700 x2251 508-457-2310 vatnipp@usgs.gov Crossref DOI link was added as the first link in the metadata. 20191118 U.S. Geological Survey VeeAnn A. Cross Marine Geologist Mailing and Physical

384 Woods Hole Road

Woods Hole MA 02543-1598 508-548-8700 x2251 508-457-2310 vatnipp@usgs.gov Added keywords section with USGS persistent identifier as theme keyword. 20200908 U.S. Geological Survey VeeAnn A. Cross Marine Geologist Mailing and Physical

384 Woods Hole Road

Woods Hole MA 02543-1598 508-548-8700 x2251 508-457-2310 vatnipp@usgs.gov Raster Pixel 4191 9986 1 0.000036 0.000048 Decimal degrees World Geodetic System 84 World Geodetic System 84 6378137 298.257 There are no attributes associated with the GEOTIFF image. U.S. Geological Survey Lawrence J. Poppe U.S. Geological Survey Geologist mailing and physical address

384 Woods Hole Road

Woods Hole MA 02543-1598 USA (508) 548-8700 x2314 (508) 457-2310 lpoppe@usgs.gov Downloadable Data: capenorthmos_geo4m_wgs84.tif Although all data have been used by the USGS, no warranty, expressed or implied, is made by the USGS as to the accuracy of the data and/or related materials. The act of distribution shall not constitute any such warranty, and no responsibility is assumed by the USGS in the use of these data or related materials. Any use of trade, product, or firm names is for descriptive purposes only and does not imply endorsement by the U.S. Government. TIFF Information unavailable from original metadata. GeoTIFF GeoTIFF format backscatter mosaic, GeoTIFF world file and associated metadata zip archive 3.4 http://pubs.usgs.gov/of/2005/1048/data/backscatter/mosaic/geo/capenorthmos_geo4m_wgs84.zip http://pubs.usgs.gov/of/2005/1048/data/backscatter/mosaic/geo/capenorthmos_geo4m_wgs84.tif http://pubs.usgs.gov/of/2005/1048/htmldocs/data_catalog.htm http://pubs.usgs.gov/of/2005/1048/data/backscatter/mosaic/geo/ Data are downloadable via the World Wide Web (WWW). DVD-ROM 4.75 Gbytes UDF 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. 2006 20240318 William Danforth U.S. Geological Survey Geologist mailing and physical address

384 Woods Hole Road

Woods Hole MA 02543-1598 USA (508) 548-8700 x2274 (508) 457-2310 whsc_data_contact@usgs.gov The metadata contact email address is a generic address in the event the person is no longer with USGS. (updated on 20240318) FGDC Content Standards for Digital Geospatial Metadata FGDC-STD-001-1998 local time None None