Multibeam bathymetric data collected in the vicinity of Buffalo Reef, Michigan, within Lake Superior during USGS Field Activity 2018-043-FA using a dual-head Reson T20-P multibeam echosounder (32-bit GeoTIFF, UTM Zone 16N, NAD 83, NAVD 88 Vertical Datum, 2-m resolution)

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Frequently anticipated questions:

What does this data set describe?

Title:
Multibeam bathymetric data collected in the vicinity of Buffalo Reef, Michigan, within Lake Superior during USGS Field Activity 2018-043-FA using a dual-head Reson T20-P multibeam echosounder (32-bit GeoTIFF, UTM Zone 16N, NAD 83, NAVD 88 Vertical Datum, 2-m resolution)
Abstract:
In September 2018, the U.S. Geological Survey, in collaboration with the U.S. Army Corps of Engineers, conducted high-resolution geophysical mapping and sediment sampling to determine the distribution of historical mine tailings on the floor of Lake Superior. Large amounts of waste material from copper mining, locally known as “stamp sands,” were dumped into the lake in the early 20th century, with wide-reaching consequences that have continued into the present. Mapping was focused offshore of the town of Gay on the Keweenaw Peninsula of Michigan, where ongoing erosion and re-deposition of the stamp sands has buried miles of native, white-sand beaches. Stamp sands are also encroaching onto Buffalo Reef, a large area of cobble/boulder substrate that supports productive fisheries in the lake. The objectives of this cooperative mapping project are to develop a framework for scientific research and provide baseline information required for management of resources within the coastal zone of northern Michigan. High-resolution bathymetry and backscatter data reveal the irregular topography of the shallow, cobble-covered Buffalo Reef and the relatively smooth surface of finer-grained sediment that covers adjacent, deeper parts of the lake floor. Previous research used numerous sediment samples to determine the general distribution of mine tailings on the lake floor in this area, but little information exists on the extent and thickness of the surficial deposits. The main priority of this project is to image the near-surface stratigraphy, specifically the thickness of surficial sand and mud that threaten to cover the reef, with seismic-reflection profiling systems. In addition to continuous coverage of bathymetric and backscatter data, this report includes a dense grid of closely spaced seismic profiles, which will guide efforts to mitigate the environmental impacts of the shifting stamp sands.
Supplemental_Information:
Data were collected using the R/V Rafael, owned and operated by the USGS Woods Hole Coastal and Marine Science Center. Additional information on the field activity is available from https://cmgds.marine.usgs.gov/fan_info.php?fan=2018-043-FA
  1. How might this data set be cited?
    U.S. Geological Survey, 20200318, Multibeam bathymetric data collected in the vicinity of Buffalo Reef, Michigan, within Lake Superior during USGS Field Activity 2018-043-FA using a dual-head Reson T20-P multibeam echosounder (32-bit GeoTIFF, UTM Zone 16N, NAD 83, NAVD 88 Vertical Datum, 2-m resolution): data release DOI:10.5066/P9K4HX8V, U.S. Geological Survey, Coastal and Marine Hazards and Resources Program, Woods Hole Coastal and Marine Science Center, Woods Hole, Massachusetts.

    Online Links:

    This is part of the following larger work.

    Andrews, Brian D., Barnhardt, Walter A., Foster, David S., Irwin, Barry J., and Nichols, Alex R., 2020, High-resolution geophysical data collected in the vicinity of Buffalo Reef, Michigan, within Lake Superior, U.S. Geological Survey Field Activity 2018-043-FA: data release DOI:10.5066/P9K4HX8V, U.S. Geological Survey, Reston, VA.

    Online Links:

    Other_Citation_Details:
    Suggested citation: Andrews, B.D., Barnhardt, W.A., Foster, D.S., Irwin, B.J., and Nichols, A.R., 2020, High-resolution geophysical data collected in the vicinity of Buffalo Reef, Michigan, within Lake Superior, U.S. Geological Survey Field Activity 2018-043-FA: U.S. Geological Survey data release, https://doi.org/10.5066/P9K4HX8V
  2. What geographic area does the data set cover?
    West_Bounding_Coordinate: -88.247070
    East_Bounding_Coordinate: -88.122144
    North_Bounding_Coordinate: 47.224536
    South_Bounding_Coordinate: 47.144453
  3. What does it look like?
    https://www.sciencebase.gov/catalog/file/get/5ddbda2ee4b06957976a56b4?name=2018-043-FA_ResonT20P_Bathymetry_2m_browse.jpg (JPEG)
    Thumbnail image of 2-m multibeam echosounder bathymetry data collected within Grand Traverse Bay, MI.
  4. Does the data set describe conditions during a particular time period?
    Beginning_Date: 15-Sep-2018
    Ending_Date: 25-Sep-2018
    Currentness_Reference:
    data were collected on the following dates: 20180915-20180919 (Julian day 258-262); 20180922 (Julian day 265); 20180925 (Julian day 268).
  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 4380 x 4667 x 1, type Pixel
    2. What coordinate system is used to represent geographic features?
      Grid_Coordinate_System_Name: Universal Transverse Mercator
      Universal_Transverse_Mercator:
      UTM_Zone_Number: 16N
      Transverse_Mercator:
      Scale_Factor_at_Central_Meridian: 0.9996
      Longitude_of_Central_Meridian: -87
      Latitude_of_Projection_Origin: 0
      False_Easting: 500000
      False_Northing: 0
      Planar coordinates are encoded using row and column
      Abscissae (x-coordinates) are specified to the nearest 2.0
      Ordinates (y-coordinates) are specified to the nearest 2.0
      Planar coordinates are specified in meters
      The horizontal datum used is GCS_North_American_1983_2011.
      The ellipsoid used is GRS_1980.
      The semi-major axis of the ellipsoid used is 6378137.000000.
      The flattening of the ellipsoid used is 1/298.257222101.
      Vertical_Coordinate_System_Definition:
      Depth_System_Definition:
      Depth_Datum_Name: North American Vertical Datum of 1988
      Depth_Resolution: 0.1
      Depth_Distance_Units: meters
      Depth_Encoding_Method: Explicit depth coordinate included with horizontal coordinates
  7. How does the data set describe geographic features?
    Entity_and_Attribute_Overview:
    Elevation values in 32-bit GeoTIFF format. Data values represent elevations referenced to the North American Vertical Datum of 1988 (NAVD 88).
    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: Brian Andrews
    Geographer
    384 Woods Hole Road
    Woods Hole, Massachusetts
    US

    508-548-8700 x2348 (voice)
    508-457-2310 (FAX)
    bandrews@usgs.gov

Why was the data set created?

The purpose of this raster depth grid is to provide a high-resolution digital elevation model (DEM) of the lake bed of Traverse Bay, MI referenced to the North American Vertical Datum of 1988 (NAVD 88).

How was the data set created?

  1. From what previous works were the data drawn?
    RAW RESON T20-P MULTIBEAM ECHOSOUNDER FILES (source 1 of 1)
    U.S. Geological Survey, Unpublished Material, raw MBES data in s7k format.

    Type_of_Source_Media: disc
    Source_Contribution:
    Multibeam echosounder (MBES) bathymetry and backscatter data were collected using dual-head Reson T20-P sonars. The pair of mills cross transmit and receive arrays were mounted side-by-side within a bracket that oriented them at opposing 30-degree angles (relative to horizontal). The bracket was pole-mounted on the starboard side of the R/V Rafael so that the sonar arrays were oriented athwart ships (primary and secondary arrays facing outward and down to port and starboard, respectively) and located approximately 1.235 m below the waterline when deployed. Vessel navigation and attitude data were acquired using an Applanix POS MV Wavemaster (model 220, V5) configured with two AeroAntenna Technologies GPS antennas located at either end of a 2-m baseline, which was oriented fore and aft and mounted atop the MBES pole approximately midships on the starboard side of vessel, and the wetpod MRU mounted atop the sonar bracket just aft of the pole. An AML Micro X SV mounted on the sonar bracket monitored sound speed near the sonars during acquisition, and an AML Minos X SVPT was used to collect water column sound speed profiles 1 to 3 times each survey day (See shapefile 2018-043-FA_SVPdata.shp available from the larger work citation). The Reson SeaBat User Interface (version 5.0.0.6) was used to control the sonars, which were operated in intermediate mode at full power (220 db), with frequency-modulated pulses between 200 to 300 kHz. The range of the 1024 across track beams formed by the sonars were adjusted manually depending on water depth, and resulted in combined swath widths of 50 to 250 meters or typically 3 to 6 times the water depth. Data were monitored and recorded using the Reson SeaBat User Interface (UI) (version 5.0.0.6) and Hypack/Hysweep (v. 2018). The SeaBat User Interface logged the navigation, attitude, bathymetry, time-series backscatter, and water column data to s7k format files for each sonar. The line files were created by the Reson UI using the following naming convention: YYYYMMDD_HHMMSS_M/S. The line files were appended with an "M" and "S" suffix to denote the port (or primary) "M" and "S" starboard (or secondary) sonar heads
  2. How were the data generated, processed, and modified?
    Date: Sep-2018 (process 1 of 5)
    PROCESSING STEP 1: CARIS HIPS DATA PROCESSING.
    Multibeam bathymetry processing within CARIS HIPS (version 10.4) during the survey consisted of the following flow:
    1) Vessel configuration files were created in CARIS for the port ("M"=main, or primary) and starboard ("S"=secondary) sonars (RVRafael_DualT20P_M.hvf, and RVRafael_DualT20P_S.hvf) which includes, linear and angular installation offsets for each T20-P unit as well as vendor specified uncertainty values for each of the survey sensors.
    2) A CARIS HIPS project (version 10.4) was created with projection information set to Universal Transverse Mercator (UTM) Zone 16N, WGS 84. Separate HIPS projects were created for the Port (M), and Starboard (S) line files using the two vessel configuration files in #1 above.
    3) Each Reson s7k file (M and S) was imported to the new CARIS projects (M and S respectively) using the Import/Conversion Wizard.
    4) Delayed heave data from raw POS MV files were used to update HIPS survey lines using the import auxiliary data function.
    5) Navigation was reviewed and edited as needed using the Navigation Editor tool.
    6) Sound velocity correction was applied using the CARIS algorithm, a master SVP file containing all the sound velocity profiles collected during the survey and specifying the nearest in distance method, delayed heave source, and use surface sound speed.
    7) Data were merged selecting no tide and the delayed heave source.
    8) 2-m resolution Swath Angle Weighted (SWATH) surfaces were created to incorporate all the files (M and S) as they were processed, and the SWATH surfaces were reviewed for inconsistencies and anomalies.
    9) The swath and subset editors were used to remove spurious points through manual editing and filter application, and the refraction editor was used to adjust sound speed values in areas where velocimeter data did not adequately correct depth profiles, which were obviously influenced by local anomalies in speed of sound through the water column.
    10) Survey lines adjusted for refraction anomalies were remerged, and the respective SWATH surfaces were recomputed to reflect the changes. Processing during the survey was primarily focused on QA/QC during acquisition. Editing processes did require trial and error, and were at times iterative. The contact person for this and all subsequent processing steps below is Brian Andrews. Person who carried out this activity:
    U.S. Geological Survey
    Attn: Brian Andrews
    Geographer
    384 Woods Hole Rd.
    Woods Hole, MA

    508-548-8700 x2348 (voice)
    508-457-2310 (FAX)
    bandrews@usgs.gov
    Date: Jan-2019 (process 2 of 5)
    PROCESSING STEP 2: APPLY POST PROCESSED SBET FILES AND EDIT SOUNDINGS.
    Post-survey processing within CARIS HIPS (version 10.4) consisted of the following flow: 1) Post-processed navigation, vessel attitude, and GPS height data from POSPac Smoothed Best Estimate of Trajectory (SBET) files, and post-processed RMS attitude error data from POSPac smrmsg files were used to update HIPS survey lines using the import auxiliary data function.
    2) Navigation source was set to Applanix SBET, and navigation was reviewed and edited as needed using the Navigation Editor tool.
    3) GPS tide was computed using delayed heave data, the vessel water line, and a single datum value of 0 m (vertically referencing the data to the WGS 84 Ellipsoid).
    4) Sound velocity correction was reapplied using the CARIS algorithm, the master SVP file containing all the sound velocity profiles collected during the survey and specifying the nearest in time method, delayed heave source, and use surface sound speed.
    5) Data were remerged selecting the GPS tide and delayed heave sources.
    6) 2-m resolution SWATH surfaces using both the M and S files were created using the Swath Angle method and a maximum footprint of 9.
    7) Additional editing was conducted using the swath and subset editors to minimize inconsistencies and artifacts, and the SWATH surface was recomputed to reflect the changes. Finally, small "no data" holidays were filled using the "Fill Raster Holiday" tool and a 5x5 cell filter using data from a minimum of 5 neighboring cells.
    Date: Jul-2019 (process 3 of 5)
    PROCESSSING STEP 3: EXPORT AND TRANSFORM TO NAVD 88.
    The CARIS HIPS SWATH surface was exported as 2-m per pixel ASCII files referenced to UTM Zone 16N, WGS 84 and WGS 84 ellipsoidal heights, but the desired vertical datum of the final composite bathymetric surface is the North American Vertical Datum of 1988 (NAVD 88). The National Oceanic and Atmospheric Administration's Vertical Datum Transformation tool (VDatum v. 3.9) was used for the transformation. The process required transformation of the horizontal and vertical reference frames from UTM Zone 16, WGS 84 and WGS 84 ellipsoidal heights to UTM Zone 16, North American Datum of 1983 (NAD 83) and NAVD 88 orthometric heights (all in meters) using the GEIOD12B geoid model. The resulting ASCII raster was exported as a 32-bit floating point GeoTIFF (2018-043-FA_T20PBathymetry_2m.tif.) using the "Data Export" tool within ArcGIS Pro (v. 2.3).
    Date: 07-Aug-2020 (process 4 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
    Date: 25-Jan-2021 (process 5 of 5)
    Changed the series issue from a URL to the DOI number. 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?

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?
    Navigation data were acquired using the WGS 84 coordinate system with an Applanix POS MV Wavemaster (model 220, V5), which blends Global Navigation Satellite Systems (GNSS) with acceleration data from a Motion Reference Unit (MRU) and GPS azimuthal heading. The POS MV was configured with two AeroAntenna Technologies GPS antennas located at either end of a 2-m baseline, which was oriented fore and aft and mounted atop the MBES pole, approximately midships on the starboard side of the R/V Rafael. DGPS positions were obtained from the primary antenna located on the forward end of the baseline, and the positional offsets between the antenna and the navigational reference point (the POS MV IMU) were accounted for in the Applanix POSView (version 8.60) acquisition software. DGPS positions are horizontally accurate to 0.5 - 2 meters, but accuracy can increase to less than 10 cm after post-processing with Applanix POSPac (version 8.1).
  3. How accurate are the heights or depths?
    Vertical accuracy of the raw data based on system specifications may be approximately 1 percent of water depth (ranging from 0.5 to 1.5 meters based on the water depth range of less than 5 meters to approximately 50 meters within the survey area). The Applanix Wavemaster POS MV Attitude and Positioning system, used to correct for vessel roll, pitch, heave, and yaw, has a theoretical vertical accuracy of a few mm. Post-Processed Kinematic (PPK) GPS height corrections (from Applanix POSPac smoothed best estimate of trajectory (SBET) files) were used to reference soundings to the World Geodetic System 1984 (WGS 84) ellipsoid and remove water depth fluctuations in lake levels during the survey. Seventeen sound speed profiles acquired with an AML Minos X SVPT sound velocity profiler were used during processing to minimize acoustic refraction artifacts in the bathymetry data. Changes in vessel draft due to water and fuel usage were not considered.
    Additionally, uncertainty associated with the vertical transformation of the bathymetric grid from WGS 84 (ITRF 2000) to the North American Vertical Datum of 1988 (NAVD 88) using VDatum transformation tool (NOAA) is approximately 7.6 cm as calculated by the VDatum tool (v. 3.9).
  4. Where are the gaps in the data? What is missing?
    Data were not collected on the following dates because of weather: Sept 20-21 (JD263-264), 23-24 (JD266-267).
  5. How consistent are the relationships among the observations, including topology?
    This grid represents processed dual-head Reson T20-P multibeam echosounder (MBES) bathymetry data gridded at 2-m resolution. Quality control and data processing were conducted to remove spurious points and reduce sound speed artifacts (refraction) using Computer Aided Resource Information System (CARIS) Hydrographic Information Processing System (HIPS v. 10.4).

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 re-distributable with proper metadata and source attribution. Please recognize the U.S. Geological Survey as the originator of the dataset. These data are not to be used for navigation.
  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? Multibeam bathymetric data collected in the vicinity of Buffalo Reef, MI within Lake Superior during USGS Field Activity 2018-043-FA using a dual-head Reson T20-P multibeam echosounder: includes the GeoTIFF image 2018-043-FA_T20P_Bathymetry_2m.tif, the browse graphic 2018-043-FA_T20P_Bathymetry_2m_browse.jpg, and Federal Geographic Data Committee (FGDC) Content Standards for Digital Geospatial Metadata (CSDGM) metadata files (2018-043-FA_T20P_Bathymetry_2m.meta.xml).
  3. What legal disclaimers am I supposed to read?
    Neither the U.S. Government, the Department of the Interior, nor the USGS, 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. Although these data and associated metadata have been reviewed for accuracy and completeness and approved for release by the U.S. Geological Survey (USGS), and have been processed successfully on a computer system at the USGS, no warranty expressed or implied is made regarding the display or utility of the data for other purposes, nor on all computer systems, nor shall the act of distribution constitute any such warranty. The USGS or the U.S. Government shall not be held liable for improper or incorrect use of the data described and/or contained herein. Any use of trade, firm, or product 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?
    To utilize these data, the user must have software capable of viewing GeoTIFF files.

Who wrote the metadata?

Dates:
Last modified: 25-Jan-2021
Metadata author:
U.S. Geological Survey
Attn: Brian Andrews
Geographer
384 Woods Hole Rd.
Woods Hole, MA

(508) 548-8700 x2348 (voice)
(508) 457-2310 (FAX)
bandrews@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_P9K4HX8V/2018-043-FA_ResonT20P_Bathymetry_2m_meta.faq.html>
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