Low-altitude aerial imagery collected from a Helikite at the Pea Island National Wildlife Refuge DUNEX Site, North Carolina in September and October 2021

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Frequently anticipated questions:

What does this data set describe?

Title:
Low-altitude aerial imagery collected from a Helikite at the Pea Island National Wildlife Refuge DUNEX Site, North Carolina in September and October 2021
Abstract:
The data in this part of the release are images of the beach for use in structure from motion that were taken with a camera attached to a helium filled balloon-kite (Helikite). During September and October 2021, USGS and Woods Hole Oceanographic Institute (WHOI) scientists conducted multiple field surveys to collect an elevation time series at the USGS DUring Nearshore Event eXperiment (DUNEX) site on Pea Island National Wildlife Refuge, NC. Agisoft Metashape (v. 1.8.1) was used to create orthomosaics and digital surface models with the collected imagery. DUNEX is a multi-agency, academic, and non-governmental organization collaborative community experiment designed to study nearshore coastal processes during storm events. USGS participation in DUNEX will contribute new measurements and models that will increase our understanding of storm impacts to coastal environments, including hazards to humans and infrastructure and changes in landscape and natural habitats.
Supplemental_Information:
For more information about the WHCMSC Field Activity, see https://cmgds.marine.usgs.gov/fan_info.php?fan=2021-029-FA. Information about the DUNEX project is available at https://usgs.gov/dunex2021. Bounding coordinates are based on image positions calculated in Metashape and may not reflect full extent of final product, and each survey did not cover the same extent.
  1. How might this data set be cited?
    Over, Jin-Si R., Sherwood, Christopher R., Traykovski, Peter A., Brosnahan, Sandra M., Randall, Noa R., and Olson, Alex J., 20220607, Low-altitude aerial imagery collected from a Helikite at the Pea Island National Wildlife Refuge DUNEX Site, North Carolina in September and 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:

    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:

    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: -75.48144554
    East_Bounding_Coordinate: -75.47881170
    North_Bounding_Coordinate: 35.68031925
    South_Bounding_Coordinate: 35.67433487
  3. What does it look like?
    https://www.sciencebase.gov/catalog/file/get/623dce3cd34e915b67d65d28?name=PINWR_Imagery_browse.jpg&allowOpen=true (JPEG)
    Example image taken of the field site from the camera attached to the Helikite.
  4. Does the data set describe conditions during a particular time period?
    Calendar_Date: 07-Sep-2021
    Currentness_Reference:
    ground condition; multiple survey days.
  5. What is the general form of this data set?
    Geospatial_Data_Presentation_Form: JPEG and comma-delimited text
  6. How does the data set represent geographic features?
    1. How are geographic features stored in the data set?
      Indirect_Spatial_Reference: provided in CSV
    2. What coordinate system is used to represent geographic features?
      Horizontal positions are specified in geographic coordinates, that is, latitude and longitude. Latitudes are given to the nearest 0.000001. Longitudes are given to the nearest 0.000001. Latitude and longitude values are specified in Decimal degrees. 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 6378137.0.
      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_photoLocations.csv contains 9788 data records.
    The CSV file contains the Metashape derived approximate position of the camera at the moment of each image capture. (Source: USGS)
    Date
    Date images were taken, in YYYYMMDD (Source: USGS) Character string.
    ImageName
    File names of individual images, see the Data Quality Information and Process Description for file naming convention. (Source: USGS) Character string.
    Latitude
    Estimated position of each image capture, in decimal degrees (NAD83[2011]). (Source: USGS)
    Range of values
    Minimum:35.674637
    Maximum:35.680146
    Units:decimal degrees
    Longitude
    Estimated position of each image capture, in decimal degrees (NAD83(2011)). Negative values represent W. (Source: None)
    Range of values
    Minimum:-75.481273
    Maximum:-75.478963
    Units:decimal degrees
    Ellipsoid_height_NAD83
    Estimated vertical position of each image capture based on the NAD83(2011) reference ellipsoid. (Source: None)
    Range of values
    Minimum:-32.497
    Maximum:6.083
    Units:meters
    Northing
    Estimated position of each image capture, in NAD83(2011)/UTM Zone 18N. (Source: USGS)
    Range of values
    Minimum:3947967.818
    Maximum:3948579.201
    Units:meters
    Easting
    Estimated position of each image capture, in NAD83(2011)/UTM Zone 18N. (Source: USGS)
    Range of values
    Minimum:456448.830
    Maximum:456655.745
    Units:meters
    Orthometric_height_NAVD88
    Estimated vertical position of each image capture, using NAVD88 (Geoid 18). (Source: USGS)
    Range of values
    Minimum:6.349
    Maximum:44.928
    Units:meters
    Entity_and_Attribute_Overview:
    The attributes are derived from Metashape after 4D alignment and optimization of all imagery and GCPs. Latitude, longitude, and ellipsoid values are in NAD83(2011), easting and northing values are in UTM18N, and Orthometric_height_NAVD88 (altitude) values are in NAVD88 Geoid18. The no-data value is represented by the string NaN.
    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)
    • Jin-Si R. Over
    • Christopher R. Sherwood
    • Peter A. Traykovski
    • Sandra M. Brosnahan
    • Noa R. Randall
    • Alex J. Olson
  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?

Images are used in structure from motion to produce the derivative orthomosaics and digital surface models used to characterize the beach at Pea Island. Image locations can be used in photogrammetry software to assist with alignment.

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: 2021 (process 1 of 2)
    These JPEG images were collected every second with a camera (either a Ricoh GRII HD or PT SONY) labeled 'aa##', where an 'r' indicates a Ricoh camera and 'pt' indicates the SONY camera, and the following 2 digits normally indicate the camera ID or last digits of the serial number. The camera was then hung from the Helikite so that the camera faces downward. The Helikite was on a 40-50 m string attached to a kitesurfing harness then walked down the beach in a pattern to get overlapping imagery of the entire field site. It is recommended when using the imagery for photogrammetric purposes to also use the ground control points (GCPs) (see larger work citation). Person who carried out this activity:
    Jin-Si R. Over
    U.S. Geological Survey, Northeast Region: Woods Hole Coastal and Marine Science Center
    Geographer
    U.S. Geological Survey
    Woods Hole, MA

    508-548-8700 x2269 (voice)
    jover@usgs.gov
    Date: 2022 (process 2 of 2)
    The images acquired with the camera were geotagged and processed to add additional information required by the USGS to the EXIF headers using ExifTools (https://exiftool.org/, version: 12.06) and the files were renamed to a unique identifier using Namexif (http://www.digicamsoft.com/softnamexif.html, version 2.1) to avoid any possibility of duplicate names. These steps are described here. 1. No GNSS navigation data was available with the photos, but relatively accurate (~1 m) estimates of camera locations were calculated in Metashape. These locations are provided for each survey in the file 2021029FA_PINWR_photoLocations.csv and includes Latitude, Longitude, and Ellipsoid height in NAD83(2011) and Easting, Northing, and Orthometric height in UTM18N NAVD88 (m). These can be loaded into photogrammetry software to assist in alignment processing. 2. Keywords were added to each image with the following command in the directory with all the photographs: exiftool -sep ", " -iptc:keywords="DUNEX, PINWR, North Carolina, 2021-029-FA, USGS, aerial imagery" *.JPG 3. Additional EXIF information (image description, artist, contact, credit, and copyright) was added in the directory with all the photos with the command: exiftool -csv=directory\name\EXIF_tags.csv *.JPG To read out the photo information to a csv when in the directory with the photos the command is: exiftool -csv *.JPG > directory/name/allheaders_out.csv For more information on tags see https://exiftool.org/TagNames/EXIF.html. 4. All the JPEG images were renamed with Namexif (https://namexif.en.uptodown.com/ v 2.2 accessed April 2020) to ensure unique filenames and compliance with the USGS Coastal and Marine Hazards and Resources Program's best practices for image naming convention. Images were renamed with a field survey ID prefix; a flight number and ID that distinguishes among USGS cameras by make, model, and camera number; the image acquisition date and coordinated universal time (UTC) in ISO8601 format, and a suffix with the original image name. For example, image name '2021029FA_f01r02_20210907T165822Z_M1050226.JPG', 2021029FA is the survey ID, f01 is the flight number, r02 is the internal camera ID, 20210907 is the UTC date in the format YYYYMMDD. A 'T' is used to separate UTC date from UTC time in format HHMMSS followed by a Z, and M1050226.JPG is the original raw photo name appended to the end of the new filename. If the camera time was collected in EST, the time in Namexif was shifted +4:00:00 to be in UTC. Person who carried out this activity:
    Jin-Si R. Over
    U.S. Geological Survey, Northeast Region: Woods Hole Coastal and Marine Science Center
    Geographer
    U.S. Geological Survey
    Woods Hole, MA

    508-548-8700 x2269 (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?
    Two cameras were used with the Helikite; the Ricoh GR II acquired 16 megapixel photos with file sizes generally between 4 and 6 MB on disc and the PT SONY acquired 24 megapixel photos with file sizes generally between 8 and 12 MB, dependent on image complexity.
  2. How accurate are the geographic locations?
    Though the images do not represent spatial data, the horizontal position of the camera as derived from Metashape after alignment and optimization is provided as a CSV. The conservative estimated horizontal accuracy is 1 m.
  3. How accurate are the heights or depths?
    Though the images do not represent spatial data, the vertical position of the camera as derived from Metashape after alignment and optimization is provided as a CSV. The conservative estimated vertical accuracy is 1 m.
  4. Where are the gaps in the data? What is missing?
    Photographs were captured every second, but as this created more images than are needed to create the structure from motion product, thus only every other image is provided for each flight. Images taken while the Helikite was launched, recovered, or held stationary for an extended period of time were removed. Images were not removed for blurriness and some photos included may not be appropriate for further use. Not all photos provided have location information as not all images successfully aligned, thus the number of images provided and number of data records for photo locations does not match. Users are advised to read the rest of the metadata record carefully for additional details.
  5. How consistent are the relationships among the observations, including topology?
    Helikite altitude was 20-40 m to map the dune and beach system at the Pea Island DUNEX site.

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. Although these data have been processed successfully on a computer system at 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. 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. Not for navigational use. Please recognize the U.S. Geological Survey (USGS) as the source of this information.
  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? Imagery from each survey are provided in individual zip folders with the suffix _imagery_date{MMDD} and the 2021029FA_PINWR_photoLocations.csv contains the combined survey photo location information. The 2021029FA_PINWR_imagery_0907.zip folder contains 736 JPEGs and is 4 GB, 2021029FA_PINWR_imagery_0908.zip folder contains 1056 JPEGs and is 5.6 GB, 2021029FA_PINWR_imagery_0911.zip folder contains 1432 JPEGs and is 7.5 GB, 2021029FA_PINWR_imagery_0919.zip folder contains 1091 JPEGs and is 5.9 GB, 2021029FA_PINWR_imagery_0925.zip folder contains 1148 JPEGs and is 6.1 GB, 2021029FA_PINWR_imagery_0926.zip folder contains 1178 JPEGs and is 6.2 GB, 2021029FA_PINWR_imagery_1003.zip file contains 1228 JPEGs and is 2.8 GB, 2021029FA_PINWR_imagery_1012.zip folder contains 2287 JPEGs and is 11.8 GB, and 2021029FA_PINWR_imagery_1019.zip folder contains 818 JPEGs and is 6.5 GB.
  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?
    Use of these files requires software capable of opening JPEG images and, if desired, capable of reading the associated EXIF information. Additionally, the location information is provided in a CSV file for the user to utilize with appropriate software.

Who wrote the metadata?

Dates:
Last modified: 07-Jun-2022
Metadata author:
Jin-Si R. Over
U.S. Geological Survey, Northeast Region: Woods Hole Coastal and Marine Science Center
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 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_P9DPZZG2/DUNEX_PINWR_imagery_metadata.faq.html>
Generated by mp version 2.9.51 on Mon Jun 27 09:45:04 2022