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Effects of Trawling and Dredging on Seafloor Habitat (2002) / Chapter Skim
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Appendix C: Mapping Tools
Pages 120-121

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From page 120...
... However, they cannot be used to make bathymetric maps, and because the incidence angle changes across the swath, the interpretation of the data is somewhat qualitative, making automatic classification of bottom types difficult. Multibeam echosounders use numerous sonar beams at a high angle of incidence with the seafloor and produce narrow swaths of bathymetric data, which can be accumulated into complete-coverage bathymetric maps (Figure Cog.
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From page 121...
... An automatic bottom classification system might be used as a preliminary reconnaissance tool to expand from a well-known area into an unknown area. The use of supporting data from substrate samples or photographic or video observations is necessary to interpret data from any of these mapping tools in terms of habitat.
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Key Terms

  • bottom classification
  • automatic bottom
  • seafloor mapping
  • incidence angle
  • bottom types

  • bathymetric maps
  • relatively smooth
  • somewhat qualitative
  • considerable interpolation
  • appropriate mapping

  • multibeam echosounders
  • sonar signal
  • low incidence
  • data requires
  • data recorded

  • backscatter data
  • tow vehicle
  • substrate texture
  • requires considerable
  • gravel bed

  • acoustic energy
  • wide swath
  • substrate samples
  • angle changes
  • numerous sonar

  • data processing
  • seafloor habitats
  • automatic classification
  • depth data
  • significant features


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