HIGHBACKSCATTER.SHP - Areas of high acoustic backscatter on the SIS-1000 1999 USGS sidescan sonar image of the Upper Continental Slope study area offshore of Louisiana

Metadata also available as - [Outline] - [Parseable text]

Frequently-anticipated questions:

What does this data set describe?

Title:
HIGHBACKSCATTER.SHP - Areas of high acoustic backscatter on the SIS-1000 1999 USGS sidescan sonar image of the Upper Continental Slope study area offshore of Louisiana
Abstract:
This GIS is a component of the U.S. Geological Survey, Woods Hole Science Center's Gulf of Mexico GIS database for gas hydrates. This database is intended to organize and display sidescan sonar, seismic-reflection, and sediment sample information collected by the USGS as well as derivative interpretations that are relevant to ongoing hydrate studies in the Gulf of Mexico.
  1. How should this data set be cited?

    Twichell, David, 2005, HIGHBACKSCATTER.SHP - Areas of high acoustic backscatter on the SIS-1000 1999 USGS sidescan sonar image of the Upper Continental Slope study area offshore of Louisiana: Open-File Report 2005-1071, U.S. Geological Survey, Coastal and Marine Geology Program, Woods Hole Science Center, Woods Hole, MA.

    Online Links:

    This is part of the following larger work.

    Twichell, D.C., Cross, V.A., Paskevich, V.F., Hutchinson, D.R., Winters, W.J., and Hart, P.E., 2005, GIS of selected geophysical and core data in the northern Gulf of Mexico continental slope collected by the U.S. Geological Survey: Open-File Report 2005-1071, U.S. Geological Survey, Coastal and Marine Geology Program, Woods Hole Science Center, Woods Hole, MA.

    Online Links:

    Other_Citation_Details: 1 DVD-ROM

  2. What geographic area does the data set cover?

    West_Bounding_Coordinate: -91.795960
    East_Bounding_Coordinate: -91.584547
    North_Bounding_Coordinate: 27.821649
    South_Bounding_Coordinate: 27.714290

  3. What does it look like?

    <http://pubs.usgs.gov/of/2005/1071/data/sidescan/interpretation/sis1000/highbackscatter-thumb.gif> (GIF)
    Thumbnail image showing the extent and content of the data layer.
    <http://pubs.usgs.gov/of/2005/1071/data/sidescan/interpretation/sis1000/highbackscatter.gif> (GIF)
    Overview image showing the extent and content of the data layer.

  4. Does the data set describe conditions during a particular time period?

    Beginning_Date: 12-Apr-1999
    Beginning_Time: 0941
    Ending_Date: 14-Apr-1999
    Ending_Time: 1544
    Currentness_Reference: ground condition

  5. What is the general form of this data set?

    Geospatial_Data_Presentation_Form: vector digital data

  6. How does the data set represent geographic features?

    1. How are geographic features stored in the data set?

      This is a Vector data set. It contains the following vector data types (SDTS terminology):

      • G-polygon (68)

    2. What coordinate system is used to represent geographic features?

      Horizontal positions are specified in geographic coordinates, that is, latitude and longitude. Latitudes are given to the nearest 0.000000. Longitudes are given to the nearest 0.000000. Latitude and longitude values are specified in Decimal degrees.

      The horizontal datum used is North American Datum of 1983.
      The ellipsoid used is Geodetic Reference System 80.
      The semi-major axis of the ellipsoid used is 6378137.000000.
      The flattening of the ellipsoid used is 1/298.257224.

  7. How does the data set describe geographic features?

    highbackscatter
    Shapefile Attribute Table (Source: ESRI)

    FID
    Internal feature number. (Source: ESRI)

    Sequential unique whole numbers that are automatically generated.

    Shape
    Feature geometry. (Source: ESRI)

    Coordinates defining the features.

    ID
    Internal feature number (Source: ESRI)

    Range of values
    Minimum:0
    Maximum:0
    Units:integer count
    Resolution:1

Who produced the data set?

  1. Who are the originators of the data set? (may include formal authors, digital compilers, and editors)

  2. Who also contributed to the data set?

  3. To whom should users address questions about the data?

    David Twichell
    U.S. Geological Survey
    Oceanographer
    384 Woods Hole Road
    Woods Hole, MA 02543-1598
    USA

    (508) 548-8700 x2266 (voice)
    (508) 457-2310 (FAX)
    dtwichell@usgs.gov

Why was the data set created?

This GIS data layer outlines the distribution of areas of high backscatter on the SIS-1000 sidescan sonar image. High-backscatter areas were those areas on the unenhanced sidescan image that were dominated by values exceeding 55.

How was the data set created?

  1. From what previous works were the data drawn?

  2. How were the data generated, processed, and modified?

    (process 1 of 1)
    The unenhanced version of the SIS-1000 sidescan sonar image was viewed in ArcView, and an interpretation was completed in which areas of the sidescan mosaic with a pixel (dn) values exceeding 55 are present.

    Person who carried out this activity:

    David Twichell
    U.S. Geological Survey
    Oceanographer
    384 Woods Hole Road
    Woods Hole, MA 02543-1598
    USA

    (508) 548-8700 x2266 (voice)
    (508) 457-2310 (FAX)
    dtwichell@usgs.gov

    Data sources used in this process:
    • sis1000un_geog.tif

    Data sources produced in this process:

    • highbackscatter.shp

  3. What similar or related data should the user be aware of?

How reliable are the data; what problems remain in the data set?

  1. How well have the observations been checked?

  2. How accurate are the geographic locations?

  3. How accurate are the heights or depths?

  4. Where are the gaps in the data? What is missing?

  5. How consistent are the relationships among the observations, including topology?

    The data layer has been checked for topological consistency.

How can someone get a copy of the data set?

Are there legal restrictions on access or use of the data?

Access_Constraints: None
Use_Constraints:
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.

  1. Who distributes the data set? (Distributor 1 of 1)

    David Twichell
    U.S. Geological Survey
    Oceanographer
    384 Woods Hole Road
    Woods Hole, MA 02543-1598
    USA

    (508) 548-8700 x2266 (voice)
    (508) 457-2310 (FAX)
    dtwichell@usgs.gov

  2. What's the catalog number I need to order this data set?

    Downloadable Data.

  3. What legal disclaimers am I supposed to read?

    Although this data set has been used by the U.S. Geological Survey (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.

  4. How can I download or order the data?

  5. What hardware or software do I need in order to use the data set?

    The data are available in Environmental Systems Research Institute (ESRI) shapefile format. The user must have ArcGIS® or ArcView® 3.0 or greater software to read and process the data file. In lieu of ArcView or ArcGIS, the user may utilize another GIS application package capable of importing data. A free data viewer, arcexplorer, capable of displaying the data is available from ESRI at www.esri.com.

Who wrote the metadata?

Dates:
Last modified: 19-Dec-2005
Metadata author:
U.S. Geological Survey
c/o David Twichell
Oceanographer
384 Woods Hole Road
Woods Hole, MA 02543-1598
USA

(508) 548-8700 x2266. (voice)
(508) 457-2310 (FAX)
dtwichell@usgs.gov

Metadata standard:
FGDC Content Standards for Digital Geospatial Metadata (FGDC-STD-001-1998)
Metadata extensions used:

Generated by mp version 2.8.6 on Mon Dec 19 11:31:30 2005