Bathymetry of the Hudson Canyon region (100-m resolution Esri binary grid and 32-bit GeoTIFF, Mercator, WGS 84)

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Frequently anticipated questions:

What does this data set describe?

Title:
Bathymetry of the Hudson Canyon region (100-m resolution Esri binary grid and 32-bit GeoTIFF, Mercator, WGS 84)
Abstract:
The Hudson Canyon begins on the outer continental shelf off the east coast of the United States at about 100-meters (m) water depth and extends offshore southeastward across the continental slope and rise. A multibeam survey was carried out in 2002 to map the bathymetry and backscatter intensity of the sea floor of the Hudson Canyon and adjacent slope and rise. The survey covered an area approximately 205 kilometers (km) in the offshore direction, extending from about 500 m to about 4,000 m water depth, and about 110 km in the alongshore direction, centered on the Hudson Canyon. The sea floor was mapped using a SeaBeam Instruments 2112 multibeam echosounder aboard the National Oceanic and Atmospheric Administration (NOAA) ship Ronald H. Brown. Maps derived from the multibeam observations show sea-floor bathymetry and backscatter intensity (a measure of sea floor texture and roughness), geomorphic provinces, and sea-floor environments (Butman and others, 2006). The sea floor was mapped by the U.S. Geological Survey in cooperation with Rutgers University and with support from NOAA.
Supplemental_Information:
Maps and interpretations of the multibeam echosounder data from the 2002 multibeam survey of the sea floor of the Hudson Canyon region are published in Butman and others (2006) (see cross reference). This publication includes the previously unpublished digital multibeam data and interpretations with FGDC-compliant metadata (CSDGM format). The data were collected on Woods Hole Coastal and Marine Science Center field activity 2002-050-FA (https://cmgds.marine.usgs.gov/fan_info.php?fan=2002-050-FA). Other datasets from the 2002 survey may be found in Butman and others (2017) (see larger work citation). Andrews and others (2013) (see cross reference) present a bathymetric terrain model for the Atlantic margin which includes the Hudson Canyon region.
  1. How might this data set be cited?
    U.S. Geological Survey, 2017, Bathymetry of the Hudson Canyon region (100-m resolution Esri binary grid and 32-bit GeoTIFF, Mercator, WGS 84): data release DOI:10.5066/F77H1GSF, 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.

    Butman, Bradford, Danforth, William W., Twichell, David C., and Rona, Peter A., 2017, Bathymetry, backscatter intensity, and geomorphology of the sea floor of the Hudson Canyon and adjacent slope and rise: data release DOI:10.5066/F77H1GSF, U.S. Geological Survey, Reston, VA.

    Online Links:

    Other_Citation_Details:
    Suggested citation: Butman, Bradford, Danforth, W.W., Twichell, D.C., and Rona, P.A., 2017, Bathymetry, backscatter intensity, and geomorphology of the sea floor of the Hudson Canyon and adjacent slope and rise: U.S. Geological Survey data release, https://doi.org/10.5066/F77H1GSF.
  2. What geographic area does the data set cover?
    West_Bounding_Coordinate: -72.517632
    East_Bounding_Coordinate: -70.071320
    North_Bounding_Coordinate: 39.845514
    South_Bounding_Coordinate: 37.610358
  3. What does it look like?
    https://www.sciencebase.gov/catalog/file/get/58fa5e8de4b0b7ea54525642?name=hc_rb_bath1_browsegraphic.jpg (JPEG)
    Browse graphic of the bathymetry of the Hudson Canyon region.
  4. Does the data set describe conditions during a particular time period?
    Beginning_Date: 27-Aug-2002
    Ending_Date: 15-Sep-2002
    Currentness_Reference:
    ground condition
  5. What is the general form of this data set?
    Geospatial_Data_Presentation_Form: raster digital data
  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 2437 x 2089 x 1, type Grid Cell
    2. What coordinate system is used to represent geographic features?
      The map projection used is Mercator.
      Projection parameters:
      Standard_Parallel: 40.000000
      Longitude_of_Central_Meridian: -75.000000
      False_Easting: 0.000000
      False_Northing: 0.000000
      Planar coordinates are encoded using row and column
      Abscissae (x-coordinates) are specified to the nearest 100.000000
      Ordinates (y-coordinates) are specified to the nearest 100.000000
      Planar coordinates are specified in meters
      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.
      Vertical_Coordinate_System_Definition:
      Altitude_System_Definition:
      Altitude_Datum_Name: local sea level
      Altitude_Resolution: 0.01
      Altitude_Distance_Units: m
      Altitude_Encoding_Method: Implicit coordinate
  7. How does the data set describe geographic features?
    Entity_and_Attribute_Overview:
    A SeaBeam Instruments 2112 multibeam Echo Sounder (12 kHz) was used to acquire the bathymetric data on the NOAA ship Ronald H. Brown. The bathymetric data are presented at a resolution of 100 m/pixel. The values are an average of the soundings within an inner 75 m circle, and a weighted average of the soundings within an outer circle that increased in size with water depth: between 500 and 1,500 m water depth, the outer circle radius was 100 m; between 1,500 and 2,500 water depth, the radius was 200 m; and for water depths greater than 2,500 m, the radius was 300 m. Water depth is reported as negative altitude relative to instantaneous sea level. Range is -351 to -4035 m. There is no tidal correction to depth.
    Entity_and_Attribute_Detail_Citation: U.S. Geological Survey

Who produced the data set?

  1. Who are the originators of the data set? (may include formal authors, digital compilers, and editors)
    • U.S. Geological Survey
  2. Who also contributed to the data set?
  3. To whom should users address questions about the data?
    U.S. Geological Survey
    Attn: Bradford Butman
    Woods Hole Coastal and Marine Science Center
    Woods Hole, MA
    USA

    508-548-8700 x2212 (voice)
    bbutman@usgs.gov

Why was the data set created?

The bathymetry shows the shape of the sea floor. Of particular interest are the shape of the canyon and features that may indicate sediment deposition or transport.

How was the data set created?

  1. From what previous works were the data drawn?
    none (source 1 of 1)
    NOAA, Bolmer, S. Thompson, Robb, James M., and Rona, Peter A., Unpublished Material, raw SeaBeam 2112 multibeam data.

    Type_of_Source_Media: disc
    Source_Contribution:
    A SeaBeam Instruments 2112 multibeam Echo Sounder (12 kHz) was used to acquire the bathymetric data on the NOAA ship Ronald H. Brown. This system utilized up to 151 electronically aimed beams spaced at intervals of 2 degrees that insonify a swath of sea floor up to 3 times the water depth. Over the continental rise, in water depths greater than about 2,000 m, a 5-km track separation was employed, which provided almost 100% overlap of the insonified area from swath to swath. Time considerations compelled less than ideal coverage of the continental slope area, where a track-line separation of about 1.7 km was used, that provided nearly no data overlap between swaths. The survey was conducted at approximately 10 knots (18.5 km/hr). The horizontal resolution of the beam on the sea floor ranged from about 20-65 m in the across-track direction and about 10 m in the along-track direction at 500 m water depth, and from about 100-400 m across-track and 40 m along-track at 3,000 m water depth. Navigation was by GPS. The data were collected on Woods Hole Coastal and Marine Science Center field activity 2002-050-FA (https://cmgds.marine.usgs.gov/fan_info.php?fan=2002-050-FA).
  2. How were the data generated, processed, and modified?
    Date: 2009 (process 1 of 5)
    A suite of processing software (called SwathEd) (Clarke, 1998; see cross reference) developed by the Ocean Mapping Group at the University of New Brunswick, Canada, was used to process, edit, grid, display, and archive the multibeam data. These routines are designed to be run on a Unix and/or Linux operating system.
    The initial processing and editing steps carried out were:
    1. Demultiplex (unravel) the SeaBeam data files using the program unravelSB2100 to generate separate files for a given raw file (filename.mb41), including depth soundings (filename.mb41.merged) and sidescan sonar backscatter values (filename.merged.mb41.ssdata).
    Command line: unravelSB2100 -declin 0.0 filename.mb41
    2. Generate a navigation file from the soundings file.
    Command line: stripNav -comp filename.mb41.nav filename.mb41.merged
    3. Edit the navigation data on-screen using the SwathEd routine jview to remove undesirable points, including turns at the ends of survey lines. Jview also rejects stray GPS fixes outside of the survey area, as set by the operator.
    Command line: jview -rejectnav -navedit filename.nav
    4. Make a copy of the edited navigation, and then create a new navigation file that has the bad fixes deleted from it.
    Command line: mv filename.nav filename.nav_all Command line: appendNav -goodonly -comp filename.nav filename.nav_all
    5. Merge the edited navigation back into the file containing the depth soundings using just the prefix of the filename. The location of the antenna relative to the motion reference unit is also entered here, along with a maximum time gap (in seconds) allowed between navigation fixes.
    Command line: mergeNav -time_limit 300 filename
    6. Edit the multibeam soundings for each trackline. SwathEd displays blocks of data across and along the trackline. Anomalous points were identified by comparison to other points and by an understanding of the sea floor geology and morphology. Anomalous soundings were removed.
    Command line: swathed filename.merged Person who carried out this activity:
    U.S. Geological Survey
    Attn: William W. Danforth
    Woods Hole Coastal and Marine Science Center
    Woods Hole, MA
    USA

    508-548-8700 x2274 (voice)
    bdanforth@usgs.gov
    Date: 2009 (process 2 of 5)
    Map the bathymetric soundings from each processed data file onto a digital terrain model (DTM) in the custom Mercator projection using weigh_grid. The bathymetric data are presented at a resolution of 100 m/pixel. The weigh_grid program creates a DTM by summing up the weighted contributions of all the provided data into the DTM. The weighted contributions only extend to a user defined region around the true location of the estimate (the cutoff). The weight of an individual point contribution decays away from the node location based on the order of the Butterworth (inverse weighting) filter (-power n), the width of the flat topped radius of the weighting function (-lambda n.n), and the absolute cutoff limit (-cutoff) that will be used for data points contributing to a node. In addition, each beam/other value can be pre-weighted if required to account for its reliability. A custom weight file for each beam is created by hand and input into the weigh_grid program using the -custom_weight option. Three files are created which are used by the weigh_grid program. An ".r4" file, which contains the grid node values in binary format, an "r4_weights" file, and an "r4_weight_depth" file. To do the summing of the weights, the .r4_weights file contains the sums of the weights for each data point contributing to the node, and the .r4_weight_depth file contains the sum of the weights x the depths. Naturally the solution is: weight_depth/weights for each node. For more information, visit the OMG website at <http://www.omg.unb.ca>. The values computed for each grid node are an average of the soundings within an inner 75 m circle, and a weighted average of the soundings within an outer circle that increased in size with water depth: between 500 and 1,500 m, the outer circle radius was 100 m, between 1,500 and 2,500, the radius was 200 m, and for depths greater than 2,500 m, the radius was 300 m.
    First a blank binary grid and the weights and weight_depth files must be created:
    Command line: make_blank -float gridFile
    This command commences a dialog to enable an 8 bit image and input the map boundaries and resolution. The program also prompts for the projection type and parameters to be used creating the binary map file (custom Mercator projection, central longitude of -75 degrees, latitude of true scale 40 degrees north).
    The next command creates the weights and weight_depth files associated with the binary grid: Command line: tor4 gridFile
    These two steps create all three files with a gridFile prefix.
    Next, each individual data file (.merged suffix) is added to the grid using weigh_grid.
    Command line: weigh_grid -omg -tide -coeffs -beam_mask -beam_weight -custom_weight RonBrownGrid_weights -butter -power 2 -cutoff 300 -lambda 75 gridFile filename.merged Person who carried out this activity:
    U.S. Geological Survey
    Attn: William W. Danforth
    Woods Hole Coastal and Marine Science Center
    Woods Hole, MA
    USA

    508-548-8700 x2274 (voice)
    bdanforth@usgs.gov
    Date: 2009 (process 3 of 5)
    Processing steps 1 and 2 produced a preliminary bathymetry dataset. Processing was carried out to further edit and correct the data and to produce final grids and images of the data. Processing and editing steps included:
    1. Correct errors in soundings due to sound refraction, caused by variations in sound velocity profile, using the SwathEd refraction tool. These artifacts can be recognized in a cross-swath profile of a relatively flat patch of sea floor. When viewing the swath data across a profile, the sea floor will appear to have a "frown" or "smile" when in fact the data should be flat across the profile. Insufficient and/or erroneous sound velocity information, which is usually due to widely spaced or non-existent velocity profiles within an area, results in an under or over-estimate of water depth which increases with distance from the center of the swath. For a discussion of how this effect can be recognized in a swath bathymetric data file, see < http://www.omg.unb.ca/AAAS/UNB_Seafloor_Mapping.html>.
    2. Remove erroneous soundings that were not edited in the field using the SwathEd program.
    3. Create a new 100 meter grid of the bathymetric soundings using the SwathEd routine weigh_grid, using different cutoff parameters based on water depth.
    Grid these files using a cutoff radius of 300 meters, lambda of 75 meters. Times: 08/30-31/2002 all, 09/01-06/2002 all, 09/07/2002 0000-0833 Times: 09/13/2002 0345-2219
    Command line: weigh_grid -omg -tide -coeffs -beam_mask -beam_weight -custom_weight RonBrownGrid_weights -butter -power 2 -cutoff 300 -lambda 75 gridFile filename.merged
    Grid these files using a cutoff radius of 200 meters. Times: 09/07/2002 0921-2359, 09/08/2002 0000-1117 Times: 09/14/2002 0813-2359, 09/15/2002 all
    Command line: weigh_grid -omg -tide -coeffs -beam_mask -beam_weight -custom_weight RonBrownGrid_weights -butter -power 2 -cutoff 200 -lambda 75 gridFile filename.merged
    Grid these files using a cutoff radius of 100 meters. Times: 09/08/2002 1152-2359, 09/09/2002 all, 09/10/2002 0000-1854 Times: 09/14/2002 0543-0743Command line: weigh_grid -omg -tide -coeffs -beam_mask -beam_weight -custom_weight RonBrownGrid_weights -butter -power 2 -cutoff 100 -lambda 75 gridFile filename.merged
    4. Convert binary bathymetric grid to Esri ASCII raster format:
    Command line: r4toASCII gridFile.r4
    This creates a file called gridFile.asc.
    Note: Errors in the UNB gridding software were identified in 2003 and 2007. These data were processed with corrected software. Person who carried out this activity:
    U.S. Geological Survey
    Attn: William W. Danforth
    Woods Hole Coastal and Marine Science Center
    Woods Hole, MA
    USA

    508-548-8700 x2274 (voice)
    bdanforth@usgs.gov
    Date: 2009 (process 4 of 5)
    Create an Esri bathymetry grid by importing data from Esri ASCII raster format into Esri grid format. Person who carried out this activity:
    U.S. Geological Survey
    Attn: William W. Danforth
    Woods Hole Coastal and Marine Science Center
    Woods Hole, MA
    USA

    508-548-8700 x2274 (voice)
    bdanforth@usgs.gov
    Date: 07-Aug-2020 (process 5 of 5)
    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?
    Butman, Bradford, Twichell, D.C., Rona, P.A., Tucholke, B.E., Middleton, T.J., and Robb, J.R., 2006, Sea floor topography and backscatter intensity of the Hudson Canyon region offshore of New York and New Jersey: Open-File Report 2004-1441, U.S. Geological Survey, Reston, VA.

    Online Links:

    Butman, Bradford, Middleton, T.J., Thieler, E.R., and Schwab, W.C., 2003, Topography, shaded relief and backscatter intensity of the Hudson Shelf Valley, offshore of New York: Open-File Report 03-372, U.S. Geological Survey, Reston, VA.

    Online Links:

    Andrews, B.D., Chaytor, J.D., ten Brink, U.S., Brothers, D.S., and Gardner, J.V., 2013, Bathymetric terrain model of the Atlantic margin for marine geological investigations: Open-File Report 2012-1266, U.S. Geological Survey, Reston, VA.

    Online Links:

    Clarke, J.H., 1998, SwathEd: Ocean Mapping Group, University of New Brunswick, New Brunswick, Canada.

    Online Links:

    Butman, Bradford, Danforth, W.W., Clarke, J.E.H., and Signell, R.P., 2017, Bathymetry and backscatter intensity of the sea floor of the Hudson Shelf Valley: data release DOI:10.5066/F7C53J1Z, 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?
    The bathymetric data are presented at a resolution of 100 m/pixel. The values are an average of the soundings within an inner 75 m circle, and a weighted average of the soundings within an outer circle that increased in size with water depth: between 500 and 1,500 m, the outer circle radius was 100 m, between 1,500 and 2,500, the radius was 200 m, and for depths greater than 2,500 m, the radius was 300 m. Navigation was by differential GPS.
  3. How accurate are the heights or depths?
    Vertical accuracy is approximately 1% of the water depth (information provided by staff on NOAA ship Ronald H. Brown).
  4. Where are the gaps in the data? What is missing?
    This grid includes bathymetry data collected with a SeaBeam Instruments 2112 multibeam mapping system on Woods Hole Coastal and Marine Science Center field activity 2002-050-FA. There are a few gaps in the grid due to incomplete coverage by the multibeam system. Other datasets from the 2002 survey of the Hudson Canyon may be found in Butman and others (2017) (see larger work citation).
  5. How consistent are the relationships among the observations, including topology?
    All data were processed in the same manner. Some features in the multibeam data are artifacts of data collection and environmental conditions. They include small highs and lows and unnatural-looking features, and patterns oriented parallel or perpendicular to survey tracklines. The orientation of the tracklines is sometimes identified by the faint parallel stripes in the image.

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: These data are not to be used for navigation purposes.
  1. Who distributes the data set? (Distributor 1 of 1)
    U.S. Geological Survey - ScienceBase
    Denver Federal Center
    Denver, CO

    1-888-275-8747 (voice)
    sciencebase@usgs.gov
  2. What's the catalog number I need to order this data set? hc_rb_bath100.zip: contains the Esri binary grid hc_rb_bath100 comprised of the hc_rb_bath100 folder and an info folder, the 32-bit GeoTIFF image and associated world file (hc_rb_bath100.tif and hc_rb_bath100.tfw), and associated FGDC compliant metadata (CSDGM format).
  3. What legal disclaimers am I supposed to read?
    Neither the U.S. Government, the Department of the Interior, nor the U.S. Geological Survey, nor any of their employees, contractors, or subcontractors, make any warranty, express or implied, nor assume any legal liability or responsibility for the accuracy, completeness, or usefulness of any information, apparatus, product, or process disclosed, nor represent that its use would not infringe on privately owned rights. 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 grid of bathymetry is compressed into a zip file (hc_rb_bath100.zip) and available through mapping services. To utilize these data available in the zip file, the user must have software capable of uncompressing the zip file and importing and viewing an Esri ArcRaster grid. The grid consists of two folders, one with the "grid name," and one "info" folder. The two folders must be uncompressed to the same folder.

Who wrote the metadata?

Dates:
Last modified: 07-Aug-2020
Metadata author:
Bradford Butman
U.S. Geological Survey
Woods Hole Coastal and Marine Science Center
Woods Hole, MA
USA

508-548-8700 x2212 (voice)
bbutman@usgs.gov
Metadata standard:
FGDC Content Standards for Digital Geospatial Metadata (FGDC-STD-001-1998)
This page is <https://cmgds.marine.usgs.gov/catalog/whcmsc/SB_data_release/DR_F77H1GSF/hc_rb_bath100_meta.faq.html>
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