Gulf of Mexico Marine Geology and Geophysics from Field Activity: A-1-97-GM: East Flower Garden Bank bathymetry and backscatter data

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Frequently anticipated questions:

What does this data set describe?

Gulf of Mexico Marine Geology and Geophysics from Field Activity: A-1-97-GM: East Flower Garden Bank bathymetry and backscatter data
Bathymetry and seafloor backscatter data for the Flower Gardens National Marine Sanctuary are provided in TIFF image format.
This data set contains data, metadata, and formal metadata associated with a marine data collection activity referred to by the USGS/CMG Activity ID: A-1-97-GM
Similar information is available for over 1500 other USGS/CMG-related Activities. If known, available are Activity-specific navigation, gravity, magnetics, bathymetry, seismic, and sampling data; track maps; and equipment information; as well as summary overviews, crew lists, and information about analog materials. Primary access to the USGS/CMG Information Bank's digital data, analog data, and metadata is provided through... This page accomodates a variety of search approaches (e.g., by ship, by region, by scientist, by equipment type, etc.).
  1. How might this data set be cited?
    Dartnell, Peter, and Gardner, James V., 1999, Gulf of Mexico Marine Geology and Geophysics from Field Activity: A-1-97-GM: East Flower Garden Bank bathymetry and backscatter data:.

    This is part of the following larger work.

    Dartnell, Peter, and Gardner, James V., 1999, Sea-Floor Images and Data from Multibeam Surveys in San Francisco Bay, Southern California, Hawaii, the Gulf of Mexico, and Lake Tahoe, California-Nevada: U.S. Geological Survey Digital Data Series DDS-55, U.S. Geological Survey, Menlo Park, CA.

    Online Links:

  2. What geographic area does the data set cover?
    West_Bounding_Coordinate: -132.00000
    East_Bounding_Coordinate: -114.00000
    North_Bounding_Coordinate: 50.00000
    South_Bounding_Coordinate: 30.00000
  3. What does it look like? (GIF)
    Index map showing area depicted in the data, with coastline and regional bathymetric contours. 491x417 pixels, 32-bit RGB true color, 30 kbytes.
  4. Does the data set describe conditions during a particular time period?
    Calendar_Date: 1997
    ground condition
  5. What is the general form of this data set?
    Geospatial_Data_Presentation_Form: remote-sensing image
  6. How does the data set represent geographic features?
    1. How are geographic features stored in the data set?
      This is a Raster data set. It contains the following raster data types:
      • Dimensions 2500 x 1974, type grid cell
    2. What coordinate system is used to represent geographic features?
      Grid_Coordinate_System_Name: Universal Transverse Mercator
      UTM_Zone_Number: 15
      Scale_Factor_at_Central_Meridian: 0.9996
      Longitude_of_Central_Meridian: -93
      Latitude_of_Projection_Origin: 0.0
      False_Easting: 500000
      False_Northing: 0.0
      Planar coordinates are encoded using row and column
      Abscissae (x-coordinates) are specified to the nearest 5
      Ordinates (y-coordinates) are specified to the nearest 5
      Planar coordinates are specified in meters
      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.
      The flattening of the ellipsoid used is 1/298.257.
  7. How does the data set describe geographic features?
    Bathymetry values are depth in meters
    Cell Size = 5.000
    Data Type: Floating Point
    Number of Rows = 2500
    Number of Columns = 1974
    Xmin = 435146.562
    Xmax = 445016.562
    Ymin = 3083306.750
    Ymax = 3095806.750
    Minimum Value = -146.037
    Maximum Value = -18.650
    Mean =  -95.788
    Standard Deviation = 23.502
    Backscatter values are a digital number (DN) associated with the reflected energy off the seafloor
    Cell Size = 5.000
    Data Type: Floating Point
    Number of Rows =  2500
    Number of Columns = 1974
    Xmin = 435146.562
    Xmax = 445016.562
    Ymin = 3083306.750
    Ymax = 3095806.750
    Minimum Value = 27.898
    Maximum Value = 231.098
    Mean = 178.342
    Standard Deviation = 9.168

Who produced the data set?

  1. Who are the originators of the data set? (may include formal authors, digital compilers, and editors)
    • Peter Dartnell
    • James V. Gardner
  2. Who also contributed to the data set?
  3. To whom should users address questions about the data?
    Peter Dartnell
    U.S. Geological Survey, GEO-WRG-MCS
    Mail Stop 999
    Bldg 15, McKelvey Building
    Menlo Park, CA

    650-329-5460 (voice)
    650-329-5411 (FAX)

Why was the data set created?

These data and information are intended for science researchers, students from elementary through college, policy makers, and general public. Pacific Seaflloor Mapping Project Test cruise.

How was the data set created?

  1. From what previous works were the data drawn?
  2. How were the data generated, processed, and modified?
    Date: Dec-1997 (process 1 of 1)
    East Flower Gardens was mapped as part of a test cruise which took place in December 1997. The data is so spectacular that is was decided to publish the data. This area was mapped using a Kongsberg Simrad EM-300 Multibeam System hull mounted to C&C Technologies' RV Ocean Alert.
    1. Bathymetry and backscatter data processed on Silicon Graphic computer using software developed by the Ocean Mapping Group, University of New Brunswick. (see USGS Open File Report 98-509, The Bathymetry of Lake Tahoe, California-Nevada)
    2. Processed data downloaded to a Sun Sparc Ultra 2, running Solaris 2.5 as an ascii file (longitude, latitude, depth, or backscatter DN value)
    3. In Arc/Info 7.1.2 a point coverage is created from the ascii file.
    4. Point coverge is projected from Geographic Coordinate System to UTM projection.
    5. Projected point coverage is gridded using IDW (Inverse Distance Weighted) function.
    6a. Grid is exported to Arc/Info export (.e00) file.
    6b. Grid is converted to a TIFF image using the "Gridimage" command.
    7. Both the export and TIFF files are compressed using UNIX version of GZIP.
  3. What similar or related data should the user be aware of?
    United States Geological Survey (USGS), Coastal and Marine Geology (CMG), Unknown, USGS/CMG Information Bank.

    Online Links:

    Other_Citation_Details: Updated daily

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?

How can someone get a copy of the data set?

Are there legal restrictions on access or use of the data?
Access_Constraints: Physical materials are under controlled on-site access.
Please recognize the U.S. Geological Survey (USGS) as the source of this information. Physical materials are under controlled on-site access. Some USGS information accessed through this means may be preliminary in nature and presented without the approval of the Director of the USGS. This information is provided with the understanding that it is not guaranteed to be correct or complete and conclusions drawn from such information are the responsibility of the user. This information is not intended for navigational purposes. Any use of trade, firm, or product names is for descriptive purposes only and does not imply endorsement by the U.S. Government.
  1. Who distributes the data set? (Distributor 1 of 1)
    USGS Information Services
    Box 25286 Denver Federal Center
    Denver, CO

    1-888-ASK-USGS (voice)
    303-202-4693 (FAX)
  2. What's the catalog number I need to order this data set? USGS Digital Data Series DDS-55
  3. What legal disclaimers am I supposed to read?
    Neither the United States Government nor any agency thereof, nor any of their employees, makes any warranty, expressed or implied, or assumes any legal liability or responsibility for the accuracy, completeness, or usefulness of any information, apparatus, product, or process disclosed in this report, or represents that its use would not infringe privately owned rights. Reference therein to any specific commercial product, process, or service by trade name, trademark, manufacturer, or otherwise does not necessarily constitute or imply its endorsement, recommendation, or favoring by the United States Government or any agency thereof.
    Although all data and software published in this report have been used by the USGS, no warranty, expressed or implied, is made by the USGS as to the accuracy of the data and related materials and (or) the functioning of the software. The act of distribution shall not constitute any such warranty, and no responsibility is assumed by the USGS in the use of this data, software, or related materials.
  4. How can I download or order the data?

Who wrote the metadata?

Last modified: 07-Jun-2016
Metadata author:
Peter N. Schweitzer
Collection manager, USGS Geoscience Data Clearinghouse,
Mail Stop 954 National Center
U.S. Geological Survey
12201 Sunrise Valley Drive
Reston, VA

(703) 648-6533 (voice)
(703) 648-6560 (FAX)
Metadata standard:
Content Standard for Digital Geospatial Metadata (FGDC-STD-001-1998)

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