Multibeam bathymetric data collected during USGS field activity 2021-004-FA, using a dual-head Teledyne SeaBat T20-P multibeam echo sounder (32-bit GeoTIFF, UTM Zone 19N, NAD 83, NAVD88 Vertical Datum, 2-m resolution)

Metadata also available as - [Outline] - [Parseable text] - [XML]

Frequently anticipated questions:

What does this data set describe?

Title:
Multibeam bathymetric data collected during USGS field activity 2021-004-FA, using a dual-head Teledyne SeaBat T20-P multibeam echo sounder (32-bit GeoTIFF, UTM Zone 19N, NAD 83, NAVD88 Vertical Datum, 2-m resolution)
Abstract:
The U.S. Geological Survey (USGS) Woods Hole Coastal and Marine Science Center (WHCMSC) completed a bathymetric and shallow seismic-reflection survey during the period of June 9, 2021 to June 24, 2021 in water depths from 2 m to 30 m for a portion of the outer Cape Cod nearshore environment between Marconi and Nauset Beaches. The products from this survey will help to support white shark research on their shallow-water behavior in the dynamic nearshore environment at Cape Cod National Seashore (CACO). CACO visitors’ safety is threatened by interactions between the public and white sharks. This project provides CACO with baseline data and information on nearshore white shark habitat, specifically in the nearshore shoreface, bathymetric trough, and longshore bar. This data release provides the geophysical data collected from outer Cape Cod during USGS Field Activities 2021-002-FA in 2021.
Supplemental_Information:
Support for 2021-004-FA was provided to the USGS from the National Park Service, Cape Cod National Seashore. Additional information on the field activities associated with this project are available at https://cmgds.marine.usgs.gov/fan_info.php?fan=2021-004-FA
  1. How might this data set be cited?
    Ackerman, Seth D., 20231114, Multibeam bathymetric data collected during USGS field activity 2021-004-FA, using a dual-head Teledyne SeaBat T20-P multibeam echo sounder (32-bit GeoTIFF, UTM Zone 19N, NAD 83, NAVD88 Vertical Datum, 2-m resolution): data release DOI:10.5066/P9GO90TI, 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.

    Ackerman, Seth D., Foster, David S., Worley, Charles R., and Nichols, Alexander R., 2023, High-resolution geophysical and geological data collected from outer Cape Cod, Massachusetts during USGS Field Activity 2021-004-FA: data release DOI:10.5066/P9GO90TI, U.S. Geological Survey, Reston, VA.

    Online Links:

    Other_Citation_Details:
    Suggested citation: Ackerman, S.D., Foster, D.S., Worley, C.R., and Nichols, A.R., 2023, High-resolution geophysical and geological data collected from outer Cape Cod, Massachusetts during USGS Field Activity 2021-004-FA: U.S. Geological Survey data release, https://doi.org/10.5066/P9GO90TI.
  2. What geographic area does the data set cover?
    West_Bounding_Coordinate: -69.98022
    East_Bounding_Coordinate: -69.90958
    North_Bounding_Coordinate: 41.94444
    South_Bounding_Coordinate: 41.78144
  3. What does it look like?
    https://cmgds.marine.usgs.gov/data-releases/media/2022/10.5066-P9GO90TI/4e4c2a14e2ee4eb3a7694072bc144ba0/2021-004-FA_T20P_Bathymetry_2m_NAVD88_browse.jpg (JPEG)
    Thumbnail image of 2-m multibeam echo sounder bathymetry data collected from outer Cape Cod, Massachusetts.
  4. Does the data set describe conditions during a particular time period?
    Beginning_Date: 09-Jun-2021
    Ending_Date: 24-Jun-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. It contains the following raster data types:
      • Dimensions 9020 x 2833 x 1, type Grid Cell
    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 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 depths 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)
    • Seth D. Ackerman
  2. Who also contributed to the data set?
  3. To whom should users address questions about the data?
    Seth Ackerman
    U.S. Geological Survey
    Geologist
    384 Woods Hole Rd.
    Woods Hole, MA
    USA

    508-548-8700 x2315 (voice)
    508-457-2310 (FAX)
    sackerman@usgs.gov

Why was the data set created?

This dataset provides a high-resolution digital elevation model (DEM) of the seabed created from bathymetric sonar data collected by the U.S. Geological Survey during survey 2021-004-FA from outer Cape Cod, Massachusetts. The final dataset is referenced to the North American Vertical Datum of 1988 (NAVD 88). In conjunction with other geophysical and sample data, this bathymetry dataset will be used to investigate the morphology and geologic framework of the sea floor and coastal environment of Massachusetts.

How was the data set created?

  1. From what previous works were the data drawn?
    Teledyne SeaBat T20P multibeam echo sounder raw bathymetry and backscatter (source 1 of 1)
    U.S. Geological Survey, Unpublished Material, raw MBES data in HSX format.

    Type_of_Source_Media: disc
    Source_Contribution:
    Multibeam echosounder (MBES) bathymetry and backscatter data were collected using dual-head Teledyne SeaBat 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 athwartship and mounted atop the aft end of 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 an AML Minos X SVPT was used to collect water column sound speed profiles 1 to 3 times each survey day. The Teledyne SeaBat User Interface (version 5.0.0.18) was used to control the sonars, which were operated in intermediate mode at full power (220 dB), with frequency-modulated pulses centered at 400 kHz. The range of across track beams (2048 for JD 160, 1024 for the rest of the survey) 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 Teledyne SeaBat User Interface (UI) (version 5.0.0.18) and Hypack Hysweep (version 2021, 21.1.3.0). The SeaBat User Interface logged the navigation, attitude, bathymetry, and time-series backscatter data to s7k format files for each sonar. The s7k line files were created by the Teledyne SeaBat UI using the following naming convention: M/S_YYYYMMDD_HHMMSS. The line files were appended with an "M" and "S" prefix to denote the port (or main/primary) "M" and "S" starboard (or secondary) sonar heads, respectively. Hypack Hysweep 2021 also was used to log the navigation, attitude, and bathymetry data for both sonars to a single HSX format file. Hypack Hysweep filenames have the format 'LLL_HHMM', where LLL indicates the three digit planned line number and HHMM is the UTC time. The Hypack Hysweep HSX data were used to produce the final processed bathymetry grid and the trackline shapefile.
  2. How were the data generated, processed, and modified?
    Date: Nov-2021 (process 1 of 3)
    PROCESSING STEP 1: CARIS HIPS DATA PROCESSING. Multibeam bathymetry processing within CARIS HIPS (version 11.3) post-survey consisted of the following flow:
    1) A vessel configuration file was created in CARIS for the HSX sonar files (RVRafael_DualT20P_2048.hvf for JD160 data, RVRafael_DualT20P.hvf for the rest of the survey) 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 11.3) was created with projection information set to Universal Transverse Mercator (UTM) Zone 19N, WGS84 using the vessel configuration file from step 1.1.
    3) Each HSX file was imported to the new CARIS project using the Import/Conversion Wizard.
    4) Delayed heave data from raw POS MV files (.000) were used to update HIPS survey lines using the import auxiliary data function.
    5) Post-processed navigation, vessel attitude, and GPS height data from POSPac 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.
    6) Navigation source was set to Applanix SBET, and navigation was reviewed and edited as needed using the Navigation Editor tool.
    7) Georeference Bathymetry was done to apply the sound velocity corrections from the final SVP files containing all the sound velocity profiles collected for each survey day, specifying the nearest in time method, 'delayed' heave source, and use surface sound speed. SVP files for each survey day were created as part of the sound velocity profile processing workflow, see SVP dataset in the larger work citation.
    8) 2-m resolution Swath Angle Weighted (SWATH) surfaces were created by sub-area to incorporate all the files 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 sound velocity data did not adequately correct depth profiles, which were obviously influenced by local anomalies in speed of sound through the water column.
    The steps described above were performed by Seth Ackerman between June and December 2021. The contact person for this and all subsequent processing steps below is Seth Ackerman. Person who carried out this activity:
    Seth Ackerman
    U.S. Geological Survey
    Geologist
    384 Woods Hole Rd.
    Woods Hole, MA
    USA

    508-548-8700 x2315 (voice)
    508-457-2310 (FAX)
    sackerman@usgs.gov
    Date: Sep-2023 (process 2 of 3)
    PROCESSING STEP 2: CREATE FINAL BATHYMETRY SURFACE. A final 2-m bathymetry SWATH surface for the entire survey area was created in CARIS 11.3. Small "no data" holidays were filled twice using the "Fill Raster Holiday" tool and a 3x3 matrix size filter using data from a minimum of 4 neighboring cells.
    Date: Sep-2023 (process 3 of 3)
    PROCESSSING STEP 3: EXPORT AND TRANSFORM TO NAVD88.
    The final CARIS HIPS SWATH surface was exported as a 2-m per pixel ASCII file referenced to UTM Zone 19N, WGS84 and ellipsoidal heights. The National Oceanic and Atmospheric Administration's Vertical Datum Transformation tool (VDatum v.4.1.2) was used to transform surfaces to the North American Vertical Datum of 1988 (NAVD 88). The process required transformation of the horizontal and vertical reference frames from UTM Zone 19N, WGS84 (using ITRF2008) and ellipsoidal heights to UTM Zone 19N, North American Datum of 1983 (NAD 83) and NAVD 88 orthometric heights (all in meters) using the default geoid model. The resulting ASCII raster was opened in Global Mapper (version 24.0) and converted into a 32-bit floating point GeoTIFF 2021-004-FA_T20P_Bathymetry2m_NAVD88.tif) using Export, Export Elevation Grid Format, GeoTIFF.
  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) data, 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 athwartship and mounted atop the aft end of cabin. 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 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 8.7).
  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 0.02 to 0.3 meters based on the water depth range of approximately 2 to 30 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 sea level during the survey. Forty-five sound speed profiles acquired with an AML Oceanographic MINOS X sound velocity profiler (SVP) 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 7.62 cm as calculated by the VDatum tool (v. 4.1.2).
  4. Where are the gaps in the data? What is missing?
    Data were collected on the following dates: 20210609 and 20210615-20210624 (Julian day 160 and 166-175); several lines of bathymetry data was collected on 20210609 (Julian day 160) while the survey team was out testing the seismic system before the formal start of the survey. Data collected during some turns and along lines that extend beyond the area of a continuous bathymetry data were excluded.
  5. How consistent are the relationships among the observations, including topology?
    This grid represents processed dual-head Teledyne SeaBat T20-P multibeam echo sounder (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; version 11.3). Despite this processing, small areas of vessel motion and refraction artifacts remain in the data. Small "no data" gaps exist throughout the dataset. These are the result of editing the artifacts and, in some areas, eliminating low quality soundings. In addition, gaps exist in shallow areas where underwater obstructions created hazards for the safe navigation of the survey vessel.
    While navigation and attitude data in the bathymetry data and coincident backscatter data (see larger work citation https://doi.org/10.5066/P9GO90TI) are identical the extents of the processed bathymetry grid and backscatter mosaic differs slightly due to differences in processing. Cross lines, collected to check tide corrections in bathymetry data and to provide dip angle seismic profile data, were incorporated into the final bathymetry dataset.

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 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
    Attn: Coastal and Marine Hazards and Resources Program
    Geologist
    384 Woods Hole Rd.
    Woods Hole, MA
    USA

    508-548-8700 x2315 (voice)
    508-457-2310 (FAX)
    whsc_data_contact@usgs.gov
  2. What's the catalog number I need to order this data set? Multibeam echo sounder 2-m bathymetry data collected from outer Cape Cod, Massachusetts during USGS Field Activity 2021-004-FA, using a dual-head Teledyne SeaBat T20-P multibeam echo sounder: includes the GeoTIFF raster 2021-004-FA_T20P_Bathymetry_2m_NAVD88.tif, world file 2021-004-FA_T20P_Bathymetry_2m_NAVD88.tfw, the browse graphic 2021-004-FA_T20P_Bathymetry_2m_NAVD88_browse.jpg, and Federal Geographic Data Committee (FGDC) Content Standards for Digital Geospatial Metadata (CSDGM) metadata files (2021-004-FA_T20P_Bathymetry_2m_NAVD88_meta.xml).
  3. What legal disclaimers am I supposed to read?
    Unless otherwise stated, all data, metadata and related materials are considered to satisfy the quality standards relative to the purpose for which the data were collected. Although these data and associated metadata have been reviewed for accuracy and completeness and approved for release by the U.S. Geological Survey (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.
  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: 14-Nov-2023
Metadata author:
Seth Ackerman
U.S. Geological Survey
Geologist
384 Woods Hole Rd.
Woods Hole, MA
USA

508-548-8700 x2315 (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)
This page is <https://cmgds.marine.usgs.gov/catalog/whcmsc/DRB_data_release/DRB_P9GO90TI/2021-004-FA_T20P_Bathymetry_2m_NAVD88_meta.faq.html>
Generated by mp version 2.9.51 on Wed Nov 15 10:11:10 2023