Bathymetry of the Historic Area Remediation Site in 1996 (3-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 Historic Area Remediation Site in 1996 (3-m resolution Esri binary grid and 32-bit GeoTIFF, Mercator, WGS 84)
Abstract:
Surveys of the bathymetry and backscatter intensity of the sea floor of the Historic Area Remediation Site (HARS), offshore of New York and New Jersey, were carried out in 1996, 1998, and 2000 using a Simrad EM1000 multibeam echosounder mounted on the Canadian Coast Guard ship Frederick G. Creed. The objective of the multiple echosounder surveys was to map the bathymetry and surficial sediments over time as dredged material was placed in the HARS to remediate contaminated sediments. Maps derived from the multibeam surveys show sea-floor bathymetry, shaded-relief bathymetry, and backscatter intensity (a measure of sea-floor texture and roughness) at a spatial resolution of 3 meters. The area was mapped by the U.S. Geological Survey in cooperation with the U.S. Army Corps of Engineers and with support from the Canadian Hydrographic Service and the University of New Brunswick.
Supplemental_Information:
This is Edition 2.0 of grid hars1996_3m. An error in the University of New Brunswick (Clarke, 1998, see cross reference) processing software that resulted in the multibeam observations not being properly projected onto a plane was discovered in 2003. A second error in the gridding algorithm was discovered in 2007, requiring a shift of 1/2 grid cell to northwest. Edition 2.0 differs from Edition 1.0 (Butman and others, 2002) in that it was processed using corrected software; comparison of the location of selected features suggests that Edition 2.0 is shifted approximately 10 m to the east compared to Edition 1.0. Maps and interpretations of these data are available in Butman and others (2002), Butman (2002), and Butman and others (2003) (citations in cross references). Other datasets from the 1996 HARS survey, as well as datasets from surveys of the HARS in 1998 and 2000, may be found in Butman and others (2017) (see larger work citation).
  1. How might this data set be cited?
    U.S. Geological Survey, and U.S. Army Corps of Engineers, 2017, Bathymetry of the Historic Area Remediation Site in 1996 (3-m resolution Esri binary grid and 32-bit GeoTIFF, Mercator, WGS 84): data release DOI:10.5066/F74B2ZGX, 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., John E. Hughes Clarke, and Signell, Richard P., 2017, Bathymetry and backscatter intensity of the sea floor of the Historic Area Remediation Site in 1996, 1998, and 2000: data release DOI:10.5066/F74B2ZGX, U.S. Geological Survey, Reston, VA.

    Online Links:

    Other_Citation_Details:
    Suggested citation: Butman, Bradford, Danforth, W.W., Clarke, J.E.H., and Signell, R.P., 2017, Bathymetry and backscatter intensity of the sea floor of the Historic Area Remediation Site in 1996, 1998, and 2000: U.S. Geological Survey data release, https://doi.org/10.5066/F74B2ZGX.
  2. What geographic area does the data set cover?
    West_Bounding_Coordinate: -73.900000
    East_Bounding_Coordinate: -73.812488
    North_Bounding_Coordinate: 40.433325
    South_Bounding_Coordinate: 40.350000
  3. What does it look like?
    https://www.sciencebase.gov/catalog/file/get/58752e7ae4b0a829a323acb1/?name=hars1996_3m_browse.jpg (JPEG)
    Browse graphic of the bathymetry data.
  4. Does the data set describe conditions during a particular time period?
    Beginning_Date: 23-Nov-1996
    Ending_Date: 27-Nov-1996
    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 3102 x 2491 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 3.000000
      Ordinates (y-coordinates) are specified to the nearest 3.000000
      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:
      Depth_System_Definition:
      Depth_Datum_Name: Mean lower low water
      Depth_Resolution: 0.01
      Depth_Distance_Units: meters
      Depth_Encoding_Method: Implicit coordinate
  7. How does the data set describe geographic features?
    Entity_and_Attribute_Overview:
    Grid of bathymetry of the Historic Area Remediation Site from multibeam survey carried out in 1996. Multibeam bathymetry in Esri ArcRaster format. Data values represent depth in meters below mean lower low water. Range is 10-38 meters.
    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
    • U.S. Army Corps of Engineers
  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 changes in the sea-floor bathymetry associated with placed dredged material or with sediment movement.

How was the data set created?

  1. From what previous works were the data drawn?
    none (source 1 of 1)
    Service, Canadian Hydrographic, Danforth, William W., and John E. Hughes Clarke, Unpublished Material, raw multibeam data.

    Type_of_Source_Media: disc
    Source_Contribution:
    The multibeam data were collected with a Simrad EM1000 multibeam echosounder mounted on the Canadian Coast Guard ship Frederick G. Creed. The multibeam system utilizes 60 electronically-aimed receive beams spaced at intervals of 2.5 degrees that insonify a strip of sea floor up to 7.5 times the water depth. The horizontal resolution of the beam on the sea floor is approximately 10 % of the water depth. Vertical resolution is approximately 1 % of the water depth. Data were collected along tracklines spaced 5-7 times the water depth apart at a speed of 10-14 knots. The HARS was surveyed in a Zamboni pattern (for efficient turns at high speed) with lines running north-south. The Zamboni pattern yields blocks of southward-run lines adjacent to blocks of northward-run lines. The frequency of the sonar was 95 kHz. Sound velocity profiles were obtained and input into the Simrad processing system to correct for refraction. Navigation was by means of differential GPS. Operation of the Simrad EM1000 was carried out by hydrographers of the Canadian Hydrographic Service. The data were collected on Woods Hole Coastal and Marine Science Center field activity 1996-043-FA (https://cmgds.marine.usgs.gov/fan_info.php?fa=1996-043-FA)
  2. How were the data generated, processed, and modified?
    Date: 1996 (process 1 of 8)
    Processing of the data was carried out by USGS personnel with assistance from the Ocean Mapping Group at the University of New Brunswick (UNB), Canada. A suite of processing software (called SwathEd) developed by the Ocean Mapping Group (Clarke, 1998; see cross reference) was used to process, edit, and archive the bathymetric soundings. These routines are designed to be run on a Unix and (or) Linux operating system. The processing and editing steps carried out on board the ship were:
    1. Demultiplex (unravel) the Simrad data files using RT to generate separate files for a given raw file (filename.raw_all) containing navigation (filename.nav), depth soundings (filename.merged), sidescan sonar backscatter values (filename.merged_ssdata), acquisition parameters (filename.param) sound velocity at the transducer (filename.sv_tdcr) and sound velocity profiler information (filename.svp).
    Command line: RT -packdown -background -WRITE -em1000 -CnC -prefix RawFiles/ -suffix _raw.all -out ProcessedFiles/InputFilenamePrefix InputFilenamePrefix
    2. 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
    3. 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
    4. 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 -ahead 5.379 -right 3.851 -below 4.244 -time_limit 300 filename
    5. 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: 1996 (process 2 of 8)
    Map the bathymetric soundings from each processed data file onto a digital terrain model (DTM) in the Mercator projection using weigh_grid with grid nodes spaced at 3 meters. 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>.
    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. The grid of HARS data were created with a grid node spacing of 3 meters, a cutoff radius of 6 meters, and an inner radius to the weighting function of 1.5 meters:
    Command line: weigh_grid -omg -tide -coeffs -mindep -2 -maxdep -800 -beam_mask -beam_weight -custom_weight EM1000_Weights -butter -power 2 -cutoff 6 -lambda 1.5 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)
    bbutman@usgs.gov
    Date: 2009 (process 3 of 8)
    Processing steps 1 and 2 produced a preliminary bathymetry data set. An error in the University of New Brunswick (Clarke, 1998, see cross reference) processing software that resulted in the multibeam observations not being properly projected onto a plane was discovered in 2003. A second error in the gridding algorithm was discovered in 2007, requiring a shift of 1/2 grid cell to northwest. This processing step uses the corrected software. Processing to further edit the data, correct for tides, and to produce the final grid of the data 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. Reference the bathymetric data to mean lower low water using the observed tidal data at Sandy Hook, NJ (NOAA tide station 8531680). The measured elevations were adjusted for fluctuations in sea level during the survey by subtracting tidal elevations predicted by a tidal model and low-frequency sea level observed at the National Oceanic and Atmospheric Administration Sandy Hook tide station located at 40 degrees 28 minutes N., 74 degrees 0.6 minutes W. The tidal model utilized nine constituents derived from a 4-month bottom pressure record obtained at Station A, located at 40 degrees 23.4 minutes N., 73 degrees 47.1 minutes W. in 38 m water depth about 2.7 km east of the HARS, during the winter of 1999-2000 (Butman, Alexander, and others, 2003; see cross references). An estimate of the error due to sea level remaining in the multibeam observations after the sea level correction is about 3 cm.
    Using the adjusted tidal elevations, create a binary tide file to be used in merging the tidal heights with the bathymetric soundings.
    Command line: binTide -year YYYY asciiTideFile BinaryTideFile
    The program mergeTide brings the swath soundings to the MLLW vertical tidal datum:
    Command line (tides): mergeTide -tide BinaryTideFile filename.merged
    4. Correct near-nadir beams for depth offset caused by error in EEPROM programming (see Logical Consistency Report)
    Command line: deHump -depscale 0.0105 filename.merged
    5. Create a new 3-meter grid of the edited bathymetric soundings from each line file (filename.merged) using the SwathEd routine weigh_grid.
    Command line: weigh_grid -fresh_start -omg -tide -coeffs -mindep -2 -maxdep -800 -beam_mask -beam_weight -custom_weight EM1000_Weights -butter -power 2 -cutoff 6 -lambda 1.5 gridFile filename.merged
    6. Convert binary bathymetric grid to Esri ASCII raster format:
    Command line: r4toASCII gridFile.r4
    This creates a file called gridFile.asc. 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 8)
    Create Esri bathymetry grid by importing data from 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: 2017 (process 5 of 8)
    ArcGIS 10.3.1 was used to export the grid to a 32-bit TIFF image. The extent and spatial reference were set to the original dataset, as was the cell size. The compression type was set to LZW. The NoData value is the default -3.40282306074e+38. The process also creates the TIFF world file automatically. 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
    Data sources used in this process:
    • hars1996_3m
    Data sources produced in this process:
    • hars1996_3m.tif
    Date: 05-Apr-2017 (process 6 of 8)
    Removed the link to the TIFF image in the distribution section. The link was invalid. 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 7 of 8)
    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: 07-Aug-2020 (process 8 of 8)
    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, Danforth, W.W., Knowles, S.C., May, Brian, and Serrett, Laurie, 2002, Seafloor topography and backscatter intensity of the Historic Area Remediation Site (HARS), offshore of New York, based on multibeam surveys conducted in 1996, 1998, and 2000: Open-File Report 00-503, U.S. Geological Survey, Reston, VA.

    Online Links:

    Butman, Bradford, 2002, Mapping the sea floor of the Historic Area Remediation Site (HARS) offshore of New York City: Fact Sheet FS-001-02, 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:

    Butman, Bradford, Alexander, P. Soupy, Harris, C.K., Traykovski, P.A., ten Brink, M.B., Lightsom, F.S., and Martini, M.A., 2003, Oceanographic observations in the Hudson Shelf Valley, December 1999 - April 2000: Data Report: Open-File Report 02-217, 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:


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?
    These data were navigated with a Differential Global Positioning System (DGPS) which is typically accurate to +/- 3 meters, horizontally. To qualitatively assess the horizontal accuracy of the 3 HARS surveys, the locations of 23 distinct features on the sea floor identified in the 1996, 1998, and 2000 shaded-relief images were compared. Offsets of features in the 1996 survey compared to the 1998 survey were typically 5 m or less, as expected when navigating with DGPS. Offsets of features in the 2000 survey compared to the 1998 survey were 10-20 m and to the north or south, the along-track direction of the survey. For 18 of the 23 features in the 2000 survey, offsets were to the north compared to the 1998 survey when the track in 2000 was to the south, and offsets were to the south compared to the 1998 survey when the track in 2000 was to the north. The offsets of the remaining 5 features, all surveyed on Julian Day 115, were in the direction of the survey track in 2000. The HARS surveys were run in a Zamboni pattern which resulted in blocks of adjacent survey lines running in the same direction; thus consistent offsets appear to shift these blocks north or south depending on the direction the lines were run. The cause of the offsets in the 2000 survey is unknown and no correction has been made for them.
  3. How accurate are the heights or depths?
    These data have been corrected for vessel motion (roll, pitch, heave, yaw). The theoretical vertical resolution of the Simrad EM-1000 multibeam echosounder is 1% of water depth, approximately 0.3 m within the study area. The measured elevations were adjusted for fluctuations in sea level during the survey by subtracting tidal elevations predicted by a tidal model and low-frequency sea level observed at the National Oceanic and Atmospheric Administration Sandy Hook tide station located at 40 degrees 28 minutes N., 74 degrees 0.6 minutes W. The tidal model utilized nine constituents derived from a 4-month bottom pressure record obtained at Station A, located at 40 degrees 23.4 minutes N., 73 degrees 47.1 minutes W. in 38 m water depth about 2.7 km east of the HARS, during the winter of 1999-2000 (Butman, Alexander, and others, 2003; see cross references). An estimate of the error due to sea level remaining in the multibeam observations after the sea level correction is about 3 cm. The vertical datum is mean lower low water.
  4. Where are the gaps in the data? What is missing?
    This grid was created from all multibeam bathymetric data collected in the Historic Area Remediation Site on WHCMSC field activity 1996-043-FA. There are a few data gaps in the grid due to incomplete coverage by the multibeam system. The 1996 survey did not map a strip approximately 900 m wide on the western side of the HARS. Other datasets from the 1996 HARS survey 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 parallel stripes in the data. During data acquisition, the electrically erasable programmable read only memory (EEPROM) within the transceiver that controls the beam launch angles was programmed with incorrect parameters for the outer ten beams on the port and starboard sides. This caused depth soundings to be deeper for these outer beams by approximately 0.1 m; these deeper depths were corrected post-acquisition by a SwathEd program called dehump, which pulls up the outer beams.

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? hars1996_3m.zip: contains the Esri binary grid hars1996_3m, comprised of the hars1996_3m folder and an info folder, the 32-bit GeoTIFF of the same data (hars1996_3m.tif and hars1996_3m.tfw), browse graphic 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 the U.S. Army Corps of Engineers, 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 (hars1996_3m.zip). To utilize these data, 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. These data are also availabe in 32-bit TIFF format and as ArcGIS REST services and WMS.

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_F74B2ZGX/hars1996_3m_meta.faq.html>
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