Interpretation of channels on the SeaMARC 1A sidescan sonar image of the Mississippi Fan, USGS Gulf of Mexico Cruise 90001 (CHANNEL.SHP)

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Frequently anticipated questions:

What does this data set describe?

Title:
Interpretation of channels on the SeaMARC 1A sidescan sonar image of the Mississippi Fan, USGS Gulf of Mexico Cruise 90001 (CHANNEL.SHP)
Abstract:
Since 1982 the U.S. Geological Survey (USGS) has collected a large amount of surficial and shallow subsurface geologic information in the deep parts of the Gulf of Mexico. These data include digital sidescan sonar imagery, digital seismic-reflection data, and descriptions and analyses of piston and gravity cores. The data were collected during several different projects that addressed surficial and shallow subsurface geologic processes. Some of these data sets have already been published, but the growing interest in the occurrence and distribution of gas hydrates in the Gulf of Mexico warrants integrating these existing data and associated interpretations into a GIS to provide regional background information for ongoing and future gas hydrate research.
  1. How might this data set be cited?
    Twichell, David, 20000404, Interpretation of channels on the SeaMARC 1A sidescan sonar image of the Mississippi Fan, USGS Gulf of Mexico Cruise 90001 (CHANNEL.SHP): Open-File Report 2005-1071, U.S. Geological Survey, Coastal and Marine Geology Program, Woods Hole Coastal and Marine Science Center, Woods Hole, MA.

    Online Links:

    This is part of the following larger work.

    D.C., Twichell, V.A., Cross, 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, Reston, VA.

    Online Links:

    Other_Citation_Details: 1 DVD-ROM
  2. What geographic area does the data set cover?
    West_Bounding_Coordinate: -86.509727
    East_Bounding_Coordinate: -85.146508
    North_Bounding_Coordinate: 26.790625
    South_Bounding_Coordinate: 26.157803
  3. What does it look like?
    https://pubs.usgs.gov/of/2005/1071/data/sidescan/interpretation/seamarc/channel-thumb.gif (GIF)
    Thumbnail image showing the extent and coverage of the data layer.
    https://pubs.usgs.gov/of/2005/1071/data/sidescan/interpretation/seamarc/channel.gif (GIF)
    Overview image showing the extent and coverage of the data layer.
  4. Does the data set describe conditions during a particular time period?
    Beginning_Date: 25-Mar-1990
    Ending_Date: 08-Apr-1990
    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):
      • String (46)
    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 0.000001. Longitudes are given to the nearest 0.000001. Latitude and longitude values are specified in Decimal degrees. The horizontal datum used is D_WGS_1984.
      The ellipsoid used is WGS_1984.
      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?
    channel
    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
    an internal control parameter automatically created during processing (Source: Software generated)
    Range of values
    Minimum:0
    Maximum:0
    Units:integer count

Who produced the data set?

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

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

Why was the data set created?

This GIS data layer contains an interpretation of channels identified on SeaMARC 1A sidescan sonar image collected on the Mississippi Fan.

How was the data set created?

  1. From what previous works were the data drawn?
    enhanced 25m SeaMARC 1A sidescan sonar mosaic (source 1 of 1)
    Twichell, Dave, 2001, Channel - polyline coverage tracing the meandering channel system of the Mississippi Fan: Open-File Report 00-352, U.S. Geological Survey, Coastal and Marine Geology Program, Woods Hole Coastal and Marine Science Center, Woods Hole, MA.

    Online Links:

    This is part of the following larger work.

    Paskevich, V., Twichell, D., and Schwab, W., 2001, SeaMARC1A sidescan mosaic, cores and depositional interpretation of the Mississippi Fan: ArcView GIS Data Release: Open-File Report 00-352, U.S. Geological Survey, Reston, VA.

    Online Links:

    Other_Citation_Details: 1 CD-ROM
    Type_of_Source_Media: CD-ROM
    Source_Contribution:
    The sidescan sonar mosaic was used as the source from which to identify the channels.
  2. How were the data generated, processed, and modified?
    Date: 28-Feb-2000 (process 1 of 7)
    The SeaMARC 1A sidescan sonar mosaic was registered and displayed in ArcView. The interpretation of the channels was then interactively drawn over the mosaic to create the ArcView GIS layer. Person who carried out this activity:
    David Twichell
    U.S. Geological Survey
    Oceanographer
    384 Woods Hole Road
    Woods Hole, MA
    USA

    (508) 548-8700 x2266 (voice)
    (508) 457-2310 (FAX)
    dtwichell@usgs.gov
    Data sources used in this process:
    • seamarc.tif
    Data sources produced in this process:
    • channel.shp
    • channel.dbf
    • channel.shx
    Date: 20-Oct-2005 (process 2 of 7)
    The projection of the shapefile was originally Geographic-NAD27, and it was changed to Geographic-WGS84 using the Project utility in ArcToolbox. Person who carried out this activity:
    David Twichell
    U.S. Geological Survey
    Oceanographer
    384 Woods Hole Road
    Woods Hole, MA
    USA

    (508) 548-8700 x2266 (voice)
    (508) 457-2310 (FAX)
    dtwichell@usgs.gov
    Data sources used in this process:
    • channel.shp
    Data sources produced in this process:
    • channel_project.shp
    Date: 20-Oct-2005 (process 3 of 7)
    Copied and renamed dataset. Person who carried out this activity:
    David Twichell
    U.S. Geological Survey
    Oceanographer
    384 Woods Hole Road
    Woods Hole, MA
    USA

    (508) 548-8700 x2266 (voice)
    (508) 457-2310 (FAX)
    dtwichell@usgs.gov
    Data sources used in this process:
    • channel_project.shp
    Data sources produced in this process:
    • channel.shp
    Date: 28-Feb-2017 (process 4 of 7)
    Edits to the metadata were made to fix any errors that MP v 2.9.36 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. Other minor edits were probably performed (title, publisher, publication place, etc.). Attempted to modify http to https where appropriate. The link to the larger work citation had to be fixed. 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. Person who carried out this activity:
    U.S. Geological Survey
    Attn: VeeAnn A. Cross
    Marine Geologist
    384 Woods Hole Road
    Woods Hole, MA

    508-548-8700 x2251 (voice)
    508-457-2310 (FAX)
    vatnipp@usgs.gov
    Date: 20-Jul-2018 (process 5 of 7)
    USGS Thesaurus keywords added to the keyword section. Person who carried out this activity:
    U.S. Geological Survey
    Attn: VeeAnn A. Cross
    Marine Geologist
    384 Woods Hole Road
    Woods Hole, MA

    508-548-8700 x2251 (voice)
    508-457-2310 (FAX)
    vatnipp@usgs.gov
    Date: 18-Nov-2019 (process 6 of 7)
    Crossref DOI link was added as the first link in the metadata. Person who carried out this activity:
    U.S. Geological Survey
    Attn: VeeAnn A. Cross
    Marine Geologist
    384 Woods Hole Road
    Woods Hole, MA

    508-548-8700 x2251 (voice)
    508-457-2310 (FAX)
    vatnipp@usgs.gov
    Date: 08-Sep-2020 (process 7 of 7)
    Added keywords section with USGS persistent identifier as theme keyword. Person who carried out this activity:
    U.S. Geological Survey
    Attn: VeeAnn A. Cross
    Marine Geologist
    384 Woods Hole Road
    Woods Hole, MA

    508-548-8700 x2251 (voice)
    508-457-2310 (FAX)
    vatnipp@usgs.gov
  3. What similar or related data should the user be aware of?
    Paskevich, V., Twichell, D., and Schwab, W., 2001, SeaMARC1A sidescan mosaic, cores and depositional interpretation of the Mississippi Fan: ArcView GIS Data Release: Open-File Report 00-352, U.S. Geological Survey, Reston, VA.

    Online Links:

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?
    Information unavailable from original metadata.
  5. How consistent are the relationships among the observations, including topology?
    No additional checks for topological consistency were performed on this data set.

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
    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?
    • Availability in digital form:
      Data format: The SHP file contains the geospatial data. The SHX file contains the index of the geospatial data. The DBF file contains the attribute data in dBase format. The PRJ file contains the coordinate system information (optional). The AVL file contains the legend information (optional). The SBN and SBX files contain the spatial index of the geospatial data (optional). The XML file contains the metadata describing the data set <data set name>.shp.xml. An ASCII version of the metadata file. A browse graphic showing the data layer coverage and extent (optional). in format SHP (version 3.3) ESRI polyline shapefile Size: 0.011
      Network links: https://pubs.usgs.gov/of/2005/1071/data/sidescan/interpretation/seamarc/channel.zip
      Media you can order: DVD-ROM (Density 4.75 Gbytes) (format UDF)
    • Cost to order the data: None

  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: 16-Nov-2021
Metadata author:
U.S. Geological Survey
Attn: Valerie Paskevich
Information Specialist, GIS Coordinator
384 Woods Hole Road
Woods Hole, MA
USA

(508) 548-8700 x2281 (voice)
(508) 457-2310 (FAX)
whsc_data_contact@usgs.gov
Contact_Instructions:
The metadata contact email address is a generic address in the event the metadata contact is no longer with the USGS or the email is otherwise invalid.
Metadata standard:
FGDC Content Standards for Digital Geospatial Metadata (FGDC-STD-001-1998)
This page is <https://cmgds.marine.usgs.gov/catalog/whcmsc/open_file_report/ofr2005-1071/channelmeta.faq.html>
Generated by mp version 2.9.50 on Tue Nov 16 10:06:30 2021