Multibeam backscatter data collected in Nantucket Sound Massachusetts in the vicinity of Horseshoe Shoal, during USGS Field Activity 2022-001-FA using a Teledyne SeaBat Integrated Dual-Head (IDH) T20-P multibeam echosounder (8-bit GeoTIFF, UTM Zone 19N, WGS 84, 1-m resolution)

Frequently anticipated questions:

• What does this data set describe?
  1. How might this data set be cited?
  2. What geographic area does the data set cover?
  3. What does it look like?
  4. Does the data set describe conditions during a particular time period?
  5. What is the general form of this data set?
  6. How does the data set represent geographic features?
  7. How does the data set describe geographic features?
• Who produced the data set?
  1. Who are the originators of the data set?
  2. Who also contributed to the data set?
  3. To whom should users address questions about the data?
• Why was the data set created?
• How was the data set created?
  1. From what previous works were the data drawn?
  2. How were the data generated, processed, and modified?
  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?
  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 data, including topology?
• How can someone get a copy of the data set?
  1. Are there legal restrictions on access or use of the data?
  2. Who distributes the data?
  3. What's the catalog number I need to order this data set?
  4. What legal disclaimers am I supposed to read?
  5. How can I download or order the data?
• Who wrote the metadata?

What does this data set describe?

1. How might this data set be cited?
   Andrews, Brian D., 20230309, Multibeam backscatter data collected in Nantucket Sound Massachusetts in the vicinity of Horseshoe Shoal, during USGS Field Activity 2022-001-FA using a Teledyne SeaBat Integrated Dual-Head (IDH) T20-P multibeam echosounder (8-bit GeoTIFF, UTM Zone 19N, WGS 84, 1-m resolution): data release DOI:10.5066/P9O5G5OT, U.S. Geological Survey, Coastal and Marine Hazards and Resources Program, Woods Hole Coastal and Marine Science Center, Woods Hole, Massachusetts.

   Online Links:

   • https://doi.org/10.5066/P9O5G5OT
   • https://www.sciencebase.gov/catalog/item/63eb9bf7d34efa0476af1f7a

   This is part of the following larger work.
   Andrews, Brian D., Baldwin, Wayne E., Worley, Charles R., Moore, Eric M., Nichols, Alex R., Danforth, William W., Foster, David S., Ackerman, Seth D., and Brothers, Laura L., 2023, High-resolution geophysical data collected in Nantucket Sound Massachusetts in the vicinity of Horseshoe Shoal, during USGS Field Activity 2022-001-FA: data release DOI:10.5066/P9O5G5OT, U.S. Geological Survey, Reston, VA.

   Online Links:

   • https://doi.org/10.5066/P9O5G5OT
   • https://www.sciencebase.gov/catalog/item/63e3e041d34e9fa19a9bb703

   Other_Citation_Details:

   Suggested citation: Andrews, B.D., Baldwin, W.E., Worley, C.R., Moore, E.M., Nichols, A.R., Danforth, W.W., Foster, D.S., Ackerman, S.D., and Brothers, L.L. 2023, High-resolution geophysical data collected in Nantucket Sound Massachusetts in the vicinity of Horseshoe Shoal, during USGS Field Activity 2022-001-FA: U.S. Geological Survey data release, https://doi.org/10.5066/P9O5G5OT

2. What geographic area does the data set cover?

   West_Bounding_Coordinate: -70.488456
   East_Bounding_Coordinate: -70.268961
   North_Bounding_Coordinate: 41.573616
   South_Bounding_Coordinate: 41.495383
   

3. What does it look like?

   https://www.sciencebase.gov/catalog/file/get/63eb9bf7d34efa0476af1f7a?name=2022-001-FA_TeledyneT20P_Backscatter_1m_browse.jpg (JPEG)

   Thumbnail image of 1-m multibeam echosounder backscatter data collected within Nantucket Sound Massachusetts in the vicinity of Horseshoe Shoal, during USGS Field Activity 2022-001-FA.

4. Does the data set describe conditions during a particular time period?

   Beginning_Date: 03-Jun-2022

   Ending_Date: 21-Jun-2022

   Currentness_Reference:

   data were collected on the following dates: 20220603-20220607 (Julian day 154-158), 20220610-20220614 (Julian day 161-165), 20220620-20220621 (Julian day 171-172). No usable bathymetry or backscatter data were collected on 20220624 (Julian Day 175).

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 10242 x 18434 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: 19N
      Transverse_Mercator:

      Scale_Factor_at_Central_Meridian: 0.9996
      Longitude_of_Central_Meridian: -69
      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 1.0
      Ordinates (y-coordinates) are specified to the nearest 1.0
      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.
      
7. How does the data set describe geographic features?

   Entity_and_Attribute_Overview: No data value is 0.
   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)
   • Brian D. Andrews
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
   

   USA

   508-548-8700 x2348 (voice)

   508-457-2310 (FAX)

   bandrews@usgs.gov

Why was the data set created?

How was the data set created?

1. From what previous works were the data drawn?

   RAW Teledyne T20-P MULTIBEAM ECHOSOUNDER FILES (source 1 of 1)

   U.S. Geological Survey, Unpublished Material, raw MBES data in Teledyne .s7k format.

   Type_of_Source_Media: disc
   Source_Contribution:

   Multibeam echosounder (MBES) bathymetry and backscatter data were collected using integrated, dual-head Teledyne 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 1.215 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 GNSS antennas located at either end of a 2-m baseline, which was oriented athwartship and mounted atop the after end of the cabin, 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 AML-3LGR or Minos X CTDSV profilers were used to collect water column sound speed profiles 3 to 7 times each survey day. The Teledyne SeaBat User Interface (version 5.2.0.1) was used to control the sonars, which were operated in intermediate mode at full power (220 dB), with frequency-modulated pulse at 400 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 300 meters or typically 3 to 6 times the water depth. Data were monitored and recorded using the Teledyne SeaBat User Interface (UI) (version 5.2.0.1) and Hypack/Hysweep (v. 2022). The SeaBat User Interface logged the navigation, attitude, bathymetry, time-series backscatter (using the normalized backscatter datagram) , and water column data to s7k format files for each sonar into one, integrated s7k file. The s7k line files were created by the Teledyne UI using the following naming convention: YYYYMMDD_HHMMSS.

2. How were the data generated, processed, and modified?

   Date: Jun-2022 (process 1 of 4)

   PROCESSING STEP 1: QIMERA DATA PROCESSING.
   Multibeam bathymetry processing within Qimera multibeam processing software (version 2.5.0) during the survey consisted of the following workflow:
   1) A new Qimera project was created with projection information set to Universal Transverse Mercator (UTM) Zone 19N, WGS 84. The s7k files for each Julian day were imported to the project using the Source/add raw sonar files menu.
   2) A Vessel configuration file was created with the linear and angular installation offsets for each T20-P sonar head as well as vendor specified uncertainty values for each of the survey sensors.
   3) Sound Velocity profiles for each day were imported and converted to Qimera using the Source/import/Caris svp menu. Each profile was reviewed for incorrect records using the SVP editor. Incorrect records near the surface or within the water column were flagged using the "reject selection" context menu.
   4) Predicted Tides from the Woods Hole, MA tidal station (id 8447930) for the month of June, were downloaded and imported using the Source/Add Tide Files menu. Predicted tides were referenced to Mean Lower Low Water (MLLW) at 6-minute intervals.
   5) Delayed heave data from the raw POS MV files (.000) were used to update raw sonar lines using the Source/add binary navigation menu function.
   6) The Processing Settings Editor was used to establish the following:
   a) Sound velocity Strategy: nearest in time, Use first entry as raytrace profile.
   b) Position, Motion, and Heading Source Priorities: were set position 1, Motion 1, and Motion 1 respectively.
   c) Vertical Referencing was set to the Woods Hole predicted Tide file.
   d) Blocking filters were set to Across Track = 0-to-80 meters on each sonar head. Colinearity Fail was also selected.
   7)Each raw sonar file was processed using the settings described above.
   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: Nov-2022 (process 2 of 4)

   PROCESSING STEP 2: APPLY POST PROCESSED SBET FILES AND EDIT SOUNDINGS.
   Post-survey processing within Qimera (version 2.5.0) consisted of the following workflow:
   1) Post-processed navigation, vessel attitude, and GNSS 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 each Sonar file using the Source/Add Binary Navigation Files function. The SBET files were referenced using the WGS 84 Ellipsoid (meters).
   2) Once the sbet and smrmsg files were imported for each raw sonar file, the Processing Settings Editor was used to replace the attitude and tide referencing data using the following settings:
   a) Position, Motion, and Heading Source Priorities were superseded by "sbet" file.
   b) Vertical Referencing Method was set to "RTK (Accurate Height)" using the "sbet" file.
   3) Each processed s7k file was exported to a generic sensor format (gsf) for creating the backscatter mosaic in FMGT software. The Export/Raw Sonar/Export To GSF menu was used with the "Include raw backscatter imagery" and "flag all filtered soundings as manual edits" options selected. Data sources produced in this process:

   • "filename.gsf"

   Date: 03-Dec-2022 (process 3 of 4)

   PROCESSSING STEP 3: IMPORT GSF FILES INTO QPS FMGT SOFTWARE.
   1) Create a new QPS FMGT (ver. 7.10.1) Project using the UTM 19, WGS 84 coordinate system. Processing parameters were set to use the "Reson SeaBat T20P Focused MBES".
   2) Import each of the integrated gsf files containing data from both heads into the project by Julian day folder. All settings were checked for the "adjust" processing section in FMGT.
   3) Filter settings used a flat Angle Varying Gain (AVG) algorithm and 300 AVG window size.

   Date: 03-Dec-2022 (process 4 of 4)

   PROCESSSING STEP 4: CREATE TIME SERIES BACKSCATTER MOSAIC AND EXPORT AS GEOTIFF.
   1) Create a 1-meter resolution mosaic using the "Beam Time Series" and "Blend" options.
   2) The mosaic was exported as an 8-bit grayscale geotiff at 1-m resolution. Data sources produced in this process:

   • 2022-001-FA_TeledyneT20P_Backscatter_1m.tif

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 utilizes multiple GNSS satellite and acceleration data from a Motion Reference Unit (MRU) and GNSS azimuthal heading. The POS MV was configured with two AeroAntenna Technologies GNSS antennas located at either end of a 2-m baseline, which was oriented athwartship and mounted atop the after end of the cabin. DGPS positions were obtained from the primary antenna located on the starboard 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 11.00) 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 8.8).
3. How accurate are the heights or depths?
   
4. Where are the gaps in the data? What is missing?
   Data collected along sonar calibration lines and cross lines used for data quality checks are not included in this mosaic, however, the trackline navigation for all lines are included in the 2022-001-FA_TeledyneT20P_Tracklines.shp shapefile included in this publication.
5. How consistent are the relationships among the observations, including topology?
   This raster mosaic represents processed dual-head Teledyne SeaBat T20-P multibeam echosounder (MBES) backscatter data gridded at 1-m resolution. Quality control and data processing were conducted to remove spurious points and reduce sound speed artifacts (refraction) using Qimera (v. 2.5) multibeam processing software.

How can someone get a copy of the data set?

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 backscatter data collected in Nantucket Sound Massachusetts in the vicinity of Horseshoe Shoal, during USGS Field Activity 2022-001-FA using a dual-head Teledyne T20-P multibeam echosounder: includes the GeoTIFF image 2022-001-FA_TeledyneT20P_Backscatter_1m.tif, the browse graphic 2022-001-FA_TeledyneT20P_Backscatter_1m_browse.jpg, and Federal Geographic Data Committee (FGDC) Content Standards for Digital Geospatial Metadata (CSDGM) metadata file (2022-001-FA_TeledyneT20P_Backscatter_1m_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?
   • Availability in digital form:

     Data format:	GeoTIFF file derived from MBES backscatter data collected by the U.S. Geological Survey - Woods Hole Coastal and Marine Science Center and the associated metadata. in format GeoTIFF (version FMGT (v. 7.10,1)) 8-bit GeoTIFF file Size: 42
     Network links:	https://www.sciencebase.gov/catalog/item/63eb9bf7d34efa0476af1f7a https://www.sciencebase.gov/catalog/file/get/63eb9bf7d34efa0476af1f7a https://doi.org/10.5066/P9O5G5OT

     Data format:	Web Mapping Service (WMS) showing MBES backscatter data collected by the U.S. Geological Survey - Woods Hole Coastal and Marine Science Center and the associated metadata. in format WMS (version v 1.3.0)
     Network links:	https://www.sciencebase.gov/catalogMaps/mapping/ows/63eb9bf7d34efa0476af1f7a?service=wms&request=getcapabilities&version=1.3.0 https://www.sciencebase.gov/catalog/file/get/63eb9bf7d34efa0476af1f7a https://doi.org/10.5066/P9O5G5OT

   • Cost to order the data: none

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: 09-Mar-2023

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)

whsc_data_contact@usgs.gov

Contact_Instructions:

The metadata contact email address is a generic address in the event the person is no longer with the USGS.

Metadata standard:

FGDC Content Standards for Digital Geospatial Metadata (FGDC-STD-001-1998)