Bathymetry data collected from ASV operations on North Core Banks, NC in October 2022

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Frequently anticipated questions:

What does this data set describe?

Title:
Bathymetry data collected from ASV operations on North Core Banks, NC in October 2022
Abstract:
These data map in high detail surficial cross-sections of North Core Banks, a barrier island in Cape Lookout National Seashore, NC, in October 2022. U.S. Geological Survey field efforts are part of an interagency agreement with the National Park Service to monitor the recovery of the island from Hurricanes Florence (2018) and Dorian (2019). Three sites of outwash, overwash, and pond formation were targeted for extensive vegetation ground-truthing, sediment samples, bathymetric mapping with a remote-controlled autonomous surface vehicle (ASV), and uncrewed aerial systems (UAS) flights to collect multispectral imagery. Five semi-permanent ground control points were also installed and surveyed to act as control for additional aerial imagery collects via plane. UAS imagery were processed in Agisoft Metashape (v. 1.8.1) with surveyed temporary ground control points to produce calibrated multispectral (red, blue, green, red edge, near infrared, and panchromatic) orthoimages and digital surface models.
Supplemental_Information:
For more information about the WHCMSC Field Activity, see https://cmgds.marine.usgs.gov/fan_info.php?fan=2022034FA. Bounding coordinates represent the maximum extent of all the bathymetry data, not the individual sites. The pond-bottom elevations relative to the NAVD88 datum, which is what the digital surface models of the surrounding pond areas are in, have not been derived here. The standard calculation would be to subtract the antenna offset of the echosounder and the depth value from the vertical position of the GPS, however the vertical uncertainties and quality check of the GPS vertical positional data does not support this method. Rather, if the pond surface is assumed to be stable and the ASV did not fluctuate more than 10-20 cm from the surface of the pond then the true depth of the pond can be determined using water’s edge elevations taken from the digital surface models available in the larger work citation. Please read the rest of the metadata for more information.
  1. How might this data set be cited?
    Over, Jin-Si R., and Sherwood, Christopher R., 20230328, Bathymetry data collected from ASV operations on North Core Banks, NC in October 2022: data release DOI:10.5066/P99IV3FC, U.S. Geological Survey, Coastal and Marine Hazards and Resources Program, Woods Hole Coastal and Marine Science Center, Woods Hole, MA.

    Online Links:

    This is part of the following larger work.

    Over, Jin-Si R., Sherwood, Christopher R., Cramer, Jennifer M., Evans, Alexandra D., and Zeigler, Sara L., 2023, Topographic, bathymetric, multispectral, vegetation, sediment, and supporting GPS data collected on North Core Banks, Cape Lookout National Seashore, North Carolina in October 2022, U.S. Geological Survey Field Activity 2022-034-FA: data release DOI:10.5066/P99IV3FC, U.S. Geological Survey, Reston, VA.

    Online Links:

    Other_Citation_Details:
    Suggested citation: Over, J.R., Sherwood, C.R., Cramer, J.M., Evans, A.D., and Zeigler, S.L, 2023, Topographic, bathymetric, multispectral, vegetation, sediment, and supporting GPS data collected on North Core Banks, Cape Lookout National Seashore, North Carolina in October 2022, U.S. Geological Survey Field Activity 2022-034-FA: U.S. Geological Survey data release, https://doi.org/10.5066/P99IV3FC.
  2. What geographic area does the data set cover?
    West_Bounding_Coordinate: -76.27113798
    East_Bounding_Coordinate: -76.22615968
    North_Bounding_Coordinate: 34.92371366
    South_Bounding_Coordinate: 34.89035797
  3. What does it look like?
    https://www.sciencebase.gov/catalog/file/get/63af0108d34e92aad3ca5ecc?name=2022034FA_NCB_bathymetry_browse.JPG&allowOpen=true (JPEG)
    Top: USGS personnel setting up the ASV Yellow Cat for a survey. Bottom: Example echogram showing the rangefinder (red dots) and corrected bottom depth (green) in Kogger open source software.
  4. Does the data set describe conditions during a particular time period?
    Calendar_Date: 18-Oct-2022
    Currentness_Reference:
    Ground condition; multiple survey days.
  5. What is the general form of this data set?
    Geospatial_Data_Presentation_Form: digital data
  6. How does the data set represent geographic features?
    1. How are geographic features stored in the data set?
      This is a Point data set. It contains the following vector data types (SDTS terminology):
      • Point (58,959)
    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: -75.000000
      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 0.001
      Ordinates (y-coordinates) are specified to the nearest 0.001
      Planar coordinates are specified in meters
      The horizontal datum used is North American Datum of 1983 (National Spatial Reference System 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
      Depth_System_Definition:
      Depth_Datum_Name: Local surface (location of echosounder)
      Depth_Resolution: 0.001
      Depth_Distance_Units: meters
      Depth_Encoding_Method: Explicit depth coordinate included with horizontal coordinates
  7. How does the data set describe geographic features?
    2022034FA_NCB_NP0_bathymetry.csv
    The CSV file contains the GNSS trackline data, bottom depths from the echosounder, and collection information from New Pond 0. This dataset contains 12,895 records. (Source: producer defined)
    INFO
    USGS Field Activity number (Source: U.S. Geological Survey, Woods Hole Coastal and Marine Science Center)
    ValueDefinition
    2022-034-FAYear, ID, and Field Activity abbreviation
    Date
    Date at which values were taken in the format MM/DD/YYYY (Source: producer defined) Character string
    ID
    Unique non-consecutive point identification (Source: producer defined)
    Range of values
    Minimum:3444
    Maximum:16356
    GPS_Time_UTC
    Time of GPS data in UTC HH:MM:SS (Source: producer defined) Character string
    Latitude_NAD83[2011]
    Emlid Reach M2 latitude solution of GNSS antenna position relative to NAD83(2011). (Source: USGS)
    Range of values
    Minimum:34.89035797
    Maximum:34.89130603
    Units:Decimal degrees
    Longitude_NAD83[2011]
    Emlid Reach M2 longitude solution of GNSS antenna position relative to NAD83(2011). (Source: USGS)
    Range of values
    Minimum:-76.27113798
    Maximum:-76.27018723
    Units:Decimal degrees
    GPS_Ellipsoid
    Emlid Reach M2 solution of the GNSS antenna position relative to the NAD83(2011) ellipsoid. Positive values are above the ellipsoid. (Source: USGS)
    Range of values
    Minimum:-39.607
    Maximum:-34.971
    Units:meters
    Northing_UTM18N
    Emlid Reach M2 GNSS antenna Y-coordinates in NAD83(2011)/UTM Zone 18N. (Source: USGS)
    Range of values
    Minimum:3861620.435
    Maximum:3861725.619
    Units:meters
    Easting_UTM18N
    Emlid Reach M2 GNSS antenna X-coordinates in NAD83(2011)/UTM Zone 18N. (Source: USGS)
    Range of values
    Minimum:383849.407
    Maximum:383936.034
    Units:meters
    GPS_Orthometric_NAVD88
    Emlid Reach M2 GNSS antenna Z-coordinates relative to NAVD88 using geoid 18. (Source: USGS)
    Range of values
    Minimum:-1.773
    Maximum:2.863
    Units:meters
    GPS_STDVns
    GPS standard deviation from the coordinate origin value in the north-south direction. (Source: Emlid)
    Range of values
    Minimum:0.059
    Maximum:0.130
    Units:meters
    GPS_STDVew
    GPS standard deviation from the coordinate origin value in the east-west direction. (Source: Emlid)
    Range of values
    Minimum:0.066
    Maximum:0.120
    Units:meters
    GPS_STDVud
    GPS standard deviation from the coordinate origin value in the up-down direction. (Source: Emlid)
    Range of values
    Minimum:0.140
    Maximum:0.240
    Units:meters
    Echo_Depth
    The corrected distance from the echosounder to the bottom. (Source: USGS)
    Range of values
    Minimum:0.060
    Maximum:1.140
    Units:meters
    2022034FA_NCB_NP1_bathymetry.csv
    The CSV file contains the GNSS trackline data, bottom depths from the echosounder, and collection information from New Pond 1. This dataset contains 14,300 records. (Source: producer defined)
    INFO
    USGS Field Activity number (Source: U.S. Geological Survey, Woods Hole Coastal and Marine Science Center)
    ValueDefinition
    2022-034-FAYear, ID, and Field Activity abbreviation
    Date
    Date at which values were taken in the format MM/DD/YYYY (Source: producer defined) Character string
    ID
    Unique non-consecutive point identification (Source: producer defined)
    Range of values
    Minimum:1144
    Maximum:15449
    GPS_Time_UTC
    Time of GPS data in UTC HH:MM:SS (Source: producer defined) Character string
    Latitude_NAD83[2011]
    Emlid Reach M2 latitude solution of GNSS antenna position relative to NAD83(2011). (Source: USGS)
    Range of values
    Minimum:34.90115252
    Maximum:34.90186637
    Units:Decimal degrees
    Longitude_NAD83[2011]
    Emlid Reach M2 longitude solution of GNSS antenna position relative to NAD83(2011). (Source: USGS)
    Range of values
    Minimum:-76.25486865
    Maximum:-76.25398568
    Units:Decimal degrees
    GPS_Ellipsoid
    Emlid Reach M2 solution of the GNSS antenna position relative to the NAD83(2011) ellipsoid. Positive values are above the ellipsoid. (Source: USGS)
    Range of values
    Minimum:-39.458
    Maximum:-34.854
    Units:meters
    Northing_UTM18N
    Emlid Reach M2 GNSS antenna Y-coordinates in NAD83(2011)/UTM Zone 18N. (Source: USGS)
    Range of values
    Minimum:3862799.173
    Maximum:3862878.491
    Units:meters
    Easting_UTM18N
    Emlid Reach M2 GNSS antenna X-coordinates in NAD83(2011)/UTM Zone 18N. (Source: USGS)
    Range of values
    Minimum:385350.927
    Maximum:385431.516
    Units:meters
    GPS_Orthometric_NAVD88
    Emlid Reach M2 GNSS antenna Z-coordinates relative to NAVD88 using geoid 18. (Source: USGS)
    Range of values
    Minimum:-1.607
    Maximum:2.997
    Units:meters
    GPS_STDVns
    GPS standard deviation from the coordinate origin value in the north-south direction. (Source: Emlid)
    Range of values
    Minimum:0.061
    Maximum:0.120
    Units:meters
    GPS_STDVew
    GPS standard deviation from the coordinate origin value in the east-west direction. (Source: Emlid)
    Range of values
    Minimum:0.082
    Maximum:0.170
    Units:meters
    GPS_STDVud
    GPS standard deviation from the coordinate origin value in the up-down direction. (Source: Emlid)
    Range of values
    Minimum:0.140
    Maximum:0.280
    Units:meters
    Echo_Depth
    The corrected distance from the echosounder to the bottom. (Source: USGS)
    Range of values
    Minimum:0.060
    Maximum:2.190
    Units:meters
    2022034FA_NCB_NP3_bathymetry.csv
    The CSV file contains the GNSS trackline data, bottom depths from the echosounder, and collection information from New Pond 3. This dataset contains 31,764 records. (Source: producer defined)
    INFO
    USGS Field Activity number (Source: U.S. Geological Survey, Woods Hole Coastal and Marine Science Center)
    ValueDefinition
    2022-034-FAYear, ID, and Field Activity abbreviation
    Date
    Date at which values were taken in the format MM/DD/YYYY (Source: producer defined) Character string
    ID
    Unique non-consecutive point identification (Source: producer defined)
    Range of values
    Minimum:756
    Maximum:34529
    GPS_Time_UTC
    Time of GPS data in UTC HH:MM:SS (Source: producer defined) Character string
    Latitude_NAD83[2011]
    Emlid Reach M2 latitude solution of GNSS antenna position relative to NAD83(2011). (Source: USGS)
    Range of values
    Minimum:34.92218556
    Maximum:34.92371366
    Units:Decimal degrees
    Longitude_NAD83[2011]
    Emlid Reach M2 longitude solution of GNSS antenna position relative to NAD83(2011). (Source: USGS)
    Range of values
    Minimum:-76.22746612
    Maximum:-76.22615968
    Units:Decimal degrees
    GPS_Ellipsoid
    Emlid Reach M2 solution of the GNSS antenna position relative to the NAD83(2011) ellipsoid. Positive values are above the ellipsoid. (Source: USGS)
    Range of values
    Minimum:-39.526
    Maximum:-34.773
    Units:meters
    Northing_UTM18N
    Emlid Reach M2 GNSS antenna Y-coordinates in NAD83(2011)/UTM Zone 18N. (Source: USGS)
    Range of values
    Minimum:3865101.347
    Maximum:3865269.943
    Units:meters
    Easting_UTM18N
    Emlid Reach M2 GNSS antenna X-coordinates in NAD83(2011)/UTM Zone 18N. (Source: USGS)
    Range of values
    Minimum:387883.096
    Maximum:388003.633
    Units:meters
    GPS_Orthometric_NAVD88
    Emlid Reach M2 GNSS antenna Z-coordinates relative to NAVD88 using geoid 18. (Source: USGS)
    Range of values
    Minimum:-1.636
    Maximum:3.116
    Units:meters
    GPS_STDVns
    GPS standard deviation from the coordinate origin value in the north-south direction. (Source: Emlid)
    Range of values
    Minimum:0.061
    Maximum:0.27
    Units:meters
    GPS_STDVew
    GPS standard deviation from the coordinate origin value in the east-west direction. (Source: Emlid)
    Range of values
    Minimum:0.064
    Maximum:0.270
    Units:meters
    GPS_STDVud
    GPS standard deviation from the coordinate origin value in the up-down direction. (Source: Emlid)
    Range of values
    Minimum:0.160
    Maximum:0.370
    Units:meters
    Echo_Depth
    The corrected distance from the echosounder to the bottom. (Source: USGS)
    Range of values
    Minimum:0.060
    Maximum:1.74
    Units:meters
    2022034FA_NCB_NP0_kogger_raw.KLF, 2022034FA_NCB_NP1_kogger_raw.KLF, and 2022034FA_NCB_NP3_kogger_raw.KLF
    The raw sonar data log files recorded from the echosounder. The files can be opened in the open source Kogger application to view the echogram, rangefinder, and post-processing points. (Source: producer defined)
    Entity_and_Attribute_Overview:
    The raw sonar files for each pond site are provided as .KLF files and clean bathymetric data are derived from the raw files and provided as CSV files. These data include echosounder depth values and GPS locations for each point.
    Entity_and_Attribute_Detail_Citation: USGS Field Activity 2022-034-FA

Who produced the data set?

  1. Who are the originators of the data set? (may include formal authors, digital compilers, and editors)
    • Jin-Si R. Over
    • Christopher R. Sherwood
  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
    384 Woods Hole Rd.
    Woods Hole, MA

    508-548-8700 x2297 (voice)
    jover@usgs.gov

Why was the data set created?

Bathymetry data collected with the Autonomous Surface Vehicle (ASV) can be used to create bottom surface grids of the ponds.

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: Oct-2022 (process 1 of 2)
    The single-beam bathymetry data were collected by launching the ASV Yellow Cat into the water from the edge of the pond. Yellow Cat is equipped with a Kogger Sonar 2D echosounder, which is integrated with an EMLID Reach M2 GPS receiver and GNSS antenna. The ASV is configured such that the batteries and wiring are contained in a box on top of the yellow pontoon floats and the GPS sits on top of the box directly above the echosounder to minimize xy offset, the z offset from the base of the antenna to the echosounder is 0.2 meters (see 2022034FA_NCB_bathymetry_browse.JPG). The boat was manually remote controlled near the shore by J. Over and C. Sherwood and driven around the edge of each pond before transects were done in a grid pattern attempting to maintain a constant speed – this was not always possible and obstacles were encountered below the surface, such as logs and branches, that interrupted a smooth continuous collection. The New Pond 3 site had three bodies of water – the GPS and echosounder were not turned off when the boat was carried across land. These sections were edited out of the file 2022034FA_NCB_NP3_bathymetry.csv.
    Date: Dec-2022 (process 2 of 2)
    The raw bathymetry data, available for download as a .KLF file was processed in the KoggerApp (v. 0.8 available for free here https://github.com/koggertech/KoggerApp) and exported as bottom depths into a CSV file. Values are positive and represent the distance from the echosounder to the bottom of the pond. The raw GPS data from the Emlid was downloaded as a .LLH file in WGS84 from the free Emlid ReachView 3 app (downloaded on October 5, 2022). No post processing was done to this file because no base position data was collected simultaneously due to an oversight. This file was opened as a simple text file and copied into Excel with columns described in the attributes section. The WGS84 latitude and longitude values were transformed to NAD83(2011) and additionally into NAD83(2011)/UTM18N + NAVD88 (m) using VDatum (ver 4.5.1 available at https://vdatum.noaa.gov/). The bathymetry and GPS data were combined and manually edited together using the KoggerApp as a reference to remove bad soundings and times when the ASV was not in the water. For each site (New Pond 0, New Pond 1, and New Pond 3), the combined GPS trackline and soundings are provided as a “bathymetry” CSV file with additional information as described in the attributes section. Person who carried out this activity:
    Jin-Si R. Over
    U.S. Geological Survey, Northeast Region, Woods Hole Coastal and Marine Science Center
    Geographer
    384 Woods Hole Rd.
    Woods Hole, MA

    508-548-8700 x2297 (voice)
    jover@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?
    No official QC test was performed, but all depth values from the echo-sounder are internally consistent in relation to each other. Data in very shallow water may not be as accurate due to turbulence and kicked up mud. The GPS data for the position of the ASV was collected with a Global Navigation Satellite System (GNSS) antenna in PPK mode, but no additional corrections have been made to it – it was observed that the vertical positional data collected was not consistent with where the ASV would have been on the surface of the ponds, which was estimated using the GPS data and digital surface models available in the larger work citation. Therefore we do not recommend using the vertical GPS positions of the ASV (Ellipsoid and Orthometric_height_NAVD88 attributes) to calculate the bottom of the ponds relative to a reference system.
  2. How accurate are the geographic locations?
    Navigation information was acquired from the GNSS receiver in PPK mode with a Multi-band GNSS antenna without further corrections because no base position was recorded. The receiver only managed to obtain a quality level of “single”, which is accurate on the meter-level or better. The horizontal standard deviations (STDV) from the coordinate origin are provided in both the north-south and east-west direction. The average north-south STDV for New Pond 0 (NP0), New Pond 1 (NP1), and New Pond 3 (NP3) was 0.074 m, 0.077 m, and 0.076 m, respectively. The average east-west STDV for NP0, NP1, and NP3 was 0.082 m, 0.096 m, and 0.082 m, respectively. When plotted, the xy positions line up well within the ponds, i.e., we have no reason to believe the positions are meters off from where the ASV actually was.
  3. How accurate are the heights or depths?
    The location information was acquired from the GNSS receiver (Emlid Reach) in PPK mode with a Multi-band GNSS antenna. The receiver only managed to obtain a quality level of “single”, which is accurate on the meter-level or better. The vertical standard deviations from the coordinate origin are provided; the average up-down STDV for NP0, NP1, and NP3 was 0.183 m, 0.173 m, and 0.188 m, respectively. The values, exported in NAD83(2011) ellipsoid and as NAVD88 geoid 18 values, do not make logistical sense for where the ASV was located on the water, which should be a relatively smooth and consistent value due to lack of waves and general stability of the boat – the vertical values do not reflect this and thus should be used with caution. However, the navigational accuracies effect the general location of the ASV and do not represent the accuracy of the derived bathymetric soundings. The vertical resolution of the echosounder for 100 Hz transmit frequencies at 5 or less meters is 1 centimeter, thus the depth values provided are more accurate than the vertical position of the boat at the time of the sounding collection.
  4. Where are the gaps in the data? What is missing?
    All collected survey line data were edited for erroneous soundings before being incorporated into the final bathymetric dataset. The CSV of trackline and echosounder values has been edited to remove returns at the beginning and end of the survey when the ASV was out of the water. Values were also removed by visualization of the data in the KoggerApp (v. 0.8 available for free here https://github.com/koggertech/KoggerApp) and points that deviated from the best estimated surface were not included in the CSV file.
  5. How consistent are the relationships among the observations, including topology?
    The files represent single beam echo-sounder bathymetry and xy trackline data collected from a small autonomous surface vehicle (ASV) built by Peter Traykovski (WHOI). The CSV files contain edited depth values from the raw Kogger SONAR 2D-BASE combined with ASV relative positions collected using a GNSS receiver (EMLID Reach M2) mounted on the ASV. The raw Kogger sonar data file is also provided so the echogram can be viewed. The CSV file is a cleaned derivative of the raw data.

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 redistributable with proper metadata and source attribution. Please recognize the U.S. Geological Survey (USGS) as the source of this information. These data are not intended for navigational use.
  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

    1-888- 275-8747 (voice)
    sciencebase@usgs.gov
  2. What's the catalog number I need to order this data set? Bathymetry data obtained from ASV system Yellow Cat.
  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?
  5. What hardware or software do I need in order to use the data set?
    The KLF files can be read using the open source Kogger application (https://github.com/koggertech/KoggerApp).

Who wrote the metadata?

Dates:
Last modified: 28-Mar-2023
Metadata author:
Jin-Si R. Over
U.S. Geological Survey, Woods Hole Coastal and Marine Science Center
Geographer
U.S. Geological Survey
Woods Hole, MA

508-548-8700 x2297 (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 USGS.
Metadata standard:
Content Standard for Digital Geospatial Metadata (FGDC-STD-001-1998)
This page is <https://cmgds.marine.usgs.gov/catalog/whcmsc/SB_data_release/DR_P99IV3FC/2022034FA_NCB_bathymetry_meta.faq.html>
Generated by mp version 2.9.51 on Tue Mar 28 17:25:49 2023