Sidescan sonar bathymetry products at the Pea Island National Wildlife Refuge DUNEX Site, North Carolina in October 2021

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?
   Traykovski, Peter A., 20220607, Sidescan sonar bathymetry products at the Pea Island National Wildlife Refuge DUNEX Site, North Carolina in October 2021: data release DOI:10.5066/P9DPZZG2, U.S. Geological Survey, Coastal and Marine Hazards and Resources Program, Woods Hole Coastal and Marine Science Center, Woods Hole, MA.

   Online Links:

   • https://doi.org/10.5066/P9DPZZG2
   • https://www.sciencebase.gov/catalog/item/624f1795d34e21f82769a75b

   This is part of the following larger work.
   Over, Jin-Si R., Sherwood, Christopher R., Traykovski, Peter A., Brosnahan, Sandra M., Olson, Alex J., and Randall, Noa R., 2022, DUNEX topographic, bathymetric, and supporting GPS data collected in Pea Island National Wildlife Refuge, North Carolina 2020-2021: data release DOI:10.5066/P9DPZZG2, U.S. Geological Survey, Reston, VA.

   Online Links:

   • https://doi.org/10.5066/P9DPZZG2
   • https://www.sciencebase.gov/catalog/item/623dca6cd34e915b67d65110

   Other_Citation_Details:

   Over, J.R., Sherwood, C.R., Traykovski, P.A., Olson, A.J., Randall, N.R., and Brosnahan, S.M., 2022, DUNEX topographic, bathymetric, and supporting GPS data collected in Pea Island National Wildlife Refuge, North Carolina 2020-2021: U.S Geological Survey data release, https://doi.org/10.5066/P9DPZZG2.

2. What geographic area does the data set cover?

   West_Bounding_Coordinate: -75.47958791
   East_Bounding_Coordinate: -75.47524654
   North_Bounding_Coordinate: 35.68043940
   South_Bounding_Coordinate: 35.67508477
   

3. What does it look like?

   https://www.sciencebase.gov/catalog/file/get/624f1795d34e21f82769a75b?name=PINWR_sidescan_browse.JPG&allowOpen=true (JPEG)

   Example bathymetry data from the sidescan USV survey in Pea Island National Wildlife Refuge.

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

   Calendar_Date: 20-Oct-2021

   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.
   2. What coordinate system is used to represent geographic features?
      

      Grid_Coordinate_System_Name: Universal Transverse Mercator
      Universal_Transverse_Mercator:

      UTM_Zone_Number: 18
      Transverse_Mercator:

      Scale_Factor_at_Central_Meridian: 0.999600
      Longitude_of_Central_Meridian: -69.000000
      Latitude_of_Projection_Origin: 0.000000
      False_Easting: 500000.000000
      False_Northing: 0.000000
      

      Planar coordinates are encoded using row and column
      Abscissae (x-coordinates) are specified to the nearest 1
      Ordinates (y-coordinates) are specified to the nearest 1
      Planar coordinates are specified in meters
      The horizontal datum used is North American Datum of 1983 NRS 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:

      Altitude_System_Definition:

      Altitude_Datum_Name: North American Vertical Datum of 1988
      Altitude_Resolution: 0.001
      Altitude_Distance_Units: meters
      Altitude_Encoding_Method:

      Explicit elevation coordinate included with horizontal coordinates

7. How does the data set describe geographic features?

   2021029FA_PINWR_DUNEX_Sidescan_bathymetry_50cm_1020.tif

   A 50 cm raster dataset (NAD83[2011]/UTM Zone 18N GeoTIFF) with encoded elevation values from sidescan sonar data collected on October 20, 2021 at the Pea Island National Wildlife Refuge DUNEX site. (Source: U.S. Geological Survey, Coastal and Marine Hazards and Resources Program)

   Value

   Seafloor elevation relative to NAVD88 (m) using Geoid 12B (Source: U.S. Geological Survey, Coastal and Marine Hazards and Resources Program)

   Range of values
   Minimum:	-6.048
   Maximum:	-2.361
   Units:	meters

   2021029FA_PINWR_DUNEX_Sidescan_bathymetry_smoothed_50cm_1020.tif

   A 50 cm raster dataset (NAD83[2011]/UTM Zone 18N GeoTIFF) with smoothed and interpolated encoded elevation values from sidescan sonar data collected on October 20, 2021 at the Pea Island National Wildlife Refuge DUNEX site. (Source: U.S. Geological Survey, Coastal and Marine Hazards and Resources Program)

   Value

   Elevation relative to NAVD88 (m) using Geoid 2012B (Source: U.S. Geological Survey, Coastal and Marine Hazards and Resources Program)

   Range of values
   Minimum:	-5.827
   Maximum:	-2.589
   Units:	meters

   2021029FA_PINWR_DUNEX_Sidescan_amplitude_50cm_1020.tif

   A 50 cm raster dataset (NAD83[2011]/UTM Zone 18N GeoTIFF) with encoded amplitude values from sidescan sonar data collected on October 20, 2021 at the Pea Island National Wildlife Refuge Basnight Bridge site. (Source: U.S. Geological Survey, Coastal and Marine Hazards and Resources Program)

   Value

   Amplitude of sidescan sonar returns (Source: U.S. Geological Survey, Coastal and Marine Hazards and Resources Program)

   Range of values
   Minimum:	35.024
   Maximum:	42.213
   Units:	relative units

   2021029FA_PINWR_DUNEX_Sidescan_amplitude_10cm_1020.tif

   A 10 cm raster dataset (NAD83[2011]/UTM Zone 18N GeoTIFF) with encoded amplitude values from sidescan sonar data collected on October 20, 2021 at the Pea Island National Wildlife Refuge Basnight Bridge site. (Source: U.S. Geological Survey, Coastal and Marine Hazards and Resources Program)

   Value

   Amplitude of sidescan sonar returns (Source: U.S. Geological Survey, Coastal and Marine Hazards and Resources Program)

   Range of values
   Minimum:	36.566
   Maximum:	42.368
   Units:	relative units

   Entity_and_Attribute_Overview:

   There are four multi-beam data grids. The no-data value is -3.402823E38. The naming convention is as follows: the USGS field ID 2021029FA; location is Pea Island National Wildlife Refuge (PINWR) at the DUNEX site; product is Sidescan bathymetry (smoothed or not) or amplitude data; resolution in centimeters; and date is in MMDD.

   Entity_and_Attribute_Detail_Citation: USGS Field Activity 2021-029-FA
   

Who produced the data set?

1. Who are the originators of the data set? (may include formal authors, digital compilers, and editors)
   • Peter A. Traykovski
2. Who also contributed to the data set?
3. To whom should users address questions about the data?
   Jin-Si R. Over

   U.S. Geological Survey, Northeast Region: Woods Hole Coastal and Marine Science Center

   U.S. Geological Survey

   Woods Hole, MA
   

   508-548-8700 x2269 (voice)

   jover@usgs.gov

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?

   Date: Apr-2022 (process 1 of 1)

   Data collected with a PingDSP 3DSS-DX-450 bathymetric sidescan sensor attached to a uncrewed surface vehicle (USV) NeedleNose. Position and velocity data (GNSS/IMU) of the USV collected using a Novatel Hexagon IMU-IGM-A1 and FlexPak6-DS2 system in the USV and corrected to a JAVAD-Triumph-2 base station. USV controlled by Peter Traykovski. 1. The GNSS and IMU data are post-processed in Novatel Inertial Explorer. The IMU to GNSS offset is xyz 0.00, 0.022, and 0.384 (in meters). 2. The raw binary files pulled from the sidescan are processed in the PingDSP 3DSS-DX-Control software using the multibeam bathymetry engine (http://www.pingdsp.com/techMBES) to produce XTF sonar files. Raw data was smoothed over 10 samples and removed points above 1.5 m and below 20 m in MBES Mode. Sonar data was also processed in Point Cloud Mode to provide a higher resolution amplitude dataset. 3. XTF files were imported into SonarWiz to merge data with the GNSS/IMU information using the navinjectorPro utility. Data were filtered using the software’s Manufacturer Flag Filter, Range Filter, Cutoff Angle Filter, and Dynamic and Static Box Filter to remove points outside of the normal range or from poor returns. 4. Bathymetric sonar data processed in MBES Mode was exported from SonarWiz using trimmed mean output with default settings at 50 cm in NAD83/UTM Zone 18N and NAVD88 meters, using Geoid 12B, as a 32-bit GeoTIFF. A secondary bathymetry product was created using regularizedata3d by Jamal (2020), a cubic interpolation with the optimum smoothness coefficient determined by a Monte Carlo optimization procedure for the data regularization. Regularizedata3d entailed removing one cross-shore line of data from the processing and adjusting the smoothness parameter so the overall surface fit best fits the removed data. The process was then repeated for all the lines of data. The optimized smoothing parameter was used with all the data for the final processing to create a smoothed and interpolated 50 cm bathymetry grid. 5. Amplitude sonar data from MBES Mode was gridded at 50 cm resolution and exported from SonarWiz using mean output and default settings as a 32-bit GeoTIFF. The amplitude sonar data processed in Point Cloud Mode was gridded at 10 cm and exported from SonarWiz using mean output and default settings as a 32-bit GeoTIFF.
   Jamal (2020). RegularizeData3D (https://www.mathworks.com/matlabcentral/fileexchange/46223-regularizedata3d), MATLAB Central File Exchange. Retrieved September 23, 2020. Person who carried out this activity:
   

   Peter A. Traykovski

   Woods Hole Oceanographic Institution

   Associate Scientist

   226 Woods Hole Rd, MS #12

   Woods Hole, MA
   

   508-289-2638 (voice)

   ptraykovski@whoi.edu

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?
   All depth values are internally consistent in relation to each other and are comparable to values of published bathymetry in the area (e.g. 2022 USGS CoNED Topobathy DEM (1851 - 2020): Coastal Carolinas, available at https://www.fisheries.noaa.gov/inport/item/67013, accessed May 18, 2022).
2. How accurate are the geographic locations?
   Navigation information was acquired from the GNSS/IMU system in PPK mode and has a theoretical horizontal accuracy of 1 cm. The horizontal accuracy of the multibeam data was not verified, but in water depths of 15 meters or less, for 450 kHz transmit frequencies, reported multibeam accuracies are less than 1 meter and likely 30-50 centimeters (Ernsten and others, 2006).
3. How accurate are the heights or depths?
   Navigation information was acquired from the GNSS/IMU system in PPK mode and has a theoretical vertical accuracy of 1-cm and average reported vertical position error of 7.6 cm. The navigational accuracies do not represent the accuracy of the derived bathymetric soundings. The vertical accuracy of the multibeam data was not verified, but in water depths of 15 meters or less, for 450 kHz transmit frequencies, reported multibeam accuracies are less than 1-meter and likely 2-10 centimeters (Ernsten and others, 2006). Ernstsen, Verner B., Riko Noormets, Dierk Hebbeln, Alex Bartholomä, and Burg W. Flemming. "Precision of high-resolution multibeam echo sounding coupled with high-accuracy positioning in a shallow water coastal environment." Geo-marine letters 26, no. 3 (2006): 141-149.
4. Where are the gaps in the data? What is missing?
   Erroneous returns were removed in processing using software and hand editing routines, see processing steps for more detail. Gaps in the raw sounding data are from the USV making transects too far apart.
5. How consistent are the relationships among the observations, including topology?
   These grids represent sidescan bathymetry data collected by Peter Traykovski (WHOI). Two products, the bathymetry and amplitude returns, are provided. The bathymetry is given as raw returns and as an interpolated raster between the stripes of data. The amplitude data are given in 50 cm and 10 cm resolutions.

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, Building 810, Mail Stop 302

   Denver, CO
   

   USA

   1-888-275-8747 (voice)

   sciencebase@usgs.gov
2. What's the catalog number I need to order this data set? Each file represents a sidescan sonar data product from the Pea Island National Wildlife Refuge DUNEX site.
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 U.S. Geological Survey 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?
   • Availability in digital form:

     Data format:	Grids of sidescan sonar data collected by Peter Traykovski (WHOI) during field activity 2021-029-FA in format GeoTIFF Size: 21
     Network links:	https://www.sciencebase.gov/catalog/file/get/624f1795d34e21f82769a75b https://www.sciencebase.gov/catalog/item/624f1795d34e21f82769a75b https://doi.org/10.5066/P9DPZZG2

   • Cost to order the data: None.

5. What hardware or software do I need in order to use the data set?
   These data are available as GeoTIFF rasters. To utilize these data, the user must have an image viewer, image processing, GIS software package capable of importing a GeoTIFF, and a way to unzip the raw data. Free spatial data viewers or proprietary software such as ArcGIS Earth or Google Earth Pro are capable of displaying the data. See: http://www.esri.com/software/arcgis-earth, or https://www.google.com/earth/desktop/.

Who wrote the metadata?

Dates:

Last modified: 07-Jun-2022

Metadata author:

Jin-Si R. Over

U.S. Geological Survey

Geographer

U.S. Geological Survey

Woods Hole, MA

508-548-8700 x2269 (voice)

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:

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