USGS CoastCam at DUNEX: Timestack Imagery and Coordinate Data (Camera 1)

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Frequently anticipated questions:

What does this data set describe?

Title:
USGS CoastCam at DUNEX: Timestack Imagery and Coordinate Data (Camera 1)
Abstract:
Two digital video cameras were temporarily installed at the U.S. Fish and Wildlife Service (USFWS) Pea Island National Wildlife Refuge (PINWR) in North Carolina (NC), as part of the DUring Nearshore Event eXperiment (DUNEX). DUNEX was a collaborative community-led experiment that took place in the fall of 2021 along the Outer Banks of NC, with the goal of improving the understanding, observational techniques, and predictive capabilities for extreme storm processes and impacts within the coastal environment. At the USFWS PINWR site, cameras were deployed for about a month, from September 18 to October 24, 2021, during which several storms passed offshore of the site. The cameras were mounted on separate 7-meter (m) tall masts within the dune, facing northeast and offshore, in a stereo configuration with approximately 75% overlap in field of view, to measure shoreline water levels and coincident topographic beach profiles. Images were collected during daylight hours with two schemes: 1) both cameras recording at 1 Hertz (Hz) for 5 minutes (min) starting 10 min before the hour for stereo photogrammetric processing to measure topographic beach profiles, and 2) one camera recording at 2 Hz for 17 min starting at the top of the hour for producing snapshots and time-averaged image products used to measure wave runup. One such product is a "runup timestack", which is created by sampling a cross-shore array of pixels from an image through time as waves propagate towards and run up a beach. Runup timestacks store the red, green, and blue (RGB) pixel intensity as a function of the cross-shore position for the sampling time period. This data release is for camera 1 timestack imagery, including coordinates in image, local, and world reference frames, which allows for quantitative measurements to be made. This camera is part of a U.S. Geological Survey (USGS) research project to study the beach and nearshore environment. USGS researchers utilize the timestack imagery collected from this camera to remotely sense information such as wave runup. This camera is part of the USGS CoastCam network. To learn more about the DUNEX camera deployment visit, https://www.usgs.gov/centers/whcmsc/science/dunex-pea-island-experiment.
Supplemental_Information:
The bounding coordinates below represent the approximate limits of the cross-shore runup timestack. This dataset represents the timestack images (in Network Common Data Form format (netCDF, .nc)) collected from the USGS CoastCam at DUNEX.
  1. How might this data set be cited?
    Brown, Jenna A., Palmsten, Margaret L., and Swanson, Eric, 20240815, USGS CoastCam at DUNEX: Timestack Imagery and Coordinate Data (Camera 1):.

    This is part of the following larger work.

    Brown, Jenna A., Palmsten, Margaret L., and Swanson, Eric, 20240815, USGS CoastCam at DUNEX: Timestack Imagery and Coordinate Data: U.S. Geological Survey data release doi:10.5066/P14EWDST, U.S. Geological Survey - St. Petersburg Coastal and Marine Science Center, St. Petersburg, Florida.

    Online Links:

  2. What geographic area does the data set cover?
    West_Bounding_Coordinate: -75.480306
    East_Bounding_Coordinate: -75.478681
    North_Bounding_Coordinate: 35.677740
    South_Bounding_Coordinate: 35.677475
  3. What does it look like?
  4. Does the data set describe conditions during a particular time period?
    Beginning_Date: 18-Sep-2021
    Ending_Date: 18-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: 0.9996
      Longitude_of_Central_Meridian: -75.0
      Latitude_of_Projection_Origin: 0.0
      False_Easting: 500000.0
      False_Northing: 0.0
      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 NAD83_National_Spatial_Reference_System_2011.
      The ellipsoid used is Geodetic Reference System 80.
      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: Attribute values
  7. How does the data set describe geographic features?
    Entity_and_Attribute_Overview:
    The Climate and Forecast (CF)-compliant metadata (version CF-1.6) in the header of each of the netCDF files provides spatial information for projecting the data into a Geographic Information System (GIS). It also provides information about the conventions used for attributes in the dataset. The column and row counts are variable between the data files.
    Entity_and_Attribute_Detail_Citation:
    The entity and attribute information were generated by the individual and/or agency identified as the originator of the dataset. Please review the rest of the metadata record for additional details and information.

Who produced the data set?

  1. Who are the originators of the data set? (may include formal authors, digital compilers, and editors)
    • Jenna A. Brown
    • Margaret L. Palmsten
    • Eric Swanson
  2. Who also contributed to the data set?
  3. To whom should users address questions about the data?
    Jenna A. Brown
    U.S. Geological Survey, St. Petersburg Coastal and Marine Science Center
    Physical Scientist
    600 4th Street South
    Saint Petersburg, FL

    (727)-502-8000 (voice)
    jennabrown@usgs.gov

Why was the data set created?

Data were obtained to measure wave runup along a cross-shore transect. These data are intended for science researchers, students, policy makers, and the public. These data can be further processed to calculate wave runup. To ensure that USGS St. Petersburg Coastal and Marine Science Center (SPCMSC) data management protocols were followed, a USGS Field Activity Number was assigned (FAN) for this camera imagery collection: 2021-340-FA. Additional information about this FAN is available on the Coastal and Marine Geoscience Data System (CMGDS): https://cmgds.marine.usgs.gov/fan_info.php?fan=2021-340-FA.

How was the data set created?

  1. From what previous works were the data drawn?
    dunex_c1_20210914_IO, dunex_c1_20210918_EO (source 1 of 2)
    Brown, Jenna A., Palmsten, Margaret L., and Swanson, Eric, 20240726, USGS CoastCam at DUNEX: Calibration Data: U.S. Geological Survey, St. Petersburg, FL.

    Online Links:

    Type_of_Source_Media: JPEG, YML, comma-delimited-text
    Source_Contribution:
    Images to solve camera intrinsic and extrinsic orientation along with solved parameters during imagery and timestack data collection during DUNEX.
    GNSS survey data (source 2 of 2)
    Over, Jin-Si R., Sherwood, Christopher R., Traykovski, Peter A., Brosnahan, Sandra M., and Olson, Alexander J., 20220607, DUNEX topographic, bathymetric, and supporting GPS data collected in Pea Island National Wildlife Refuge, North Carolina 2020-2021: U.S. Geological Survey, Reston, VA.

    Online Links:

    Type_of_Source_Media: comma-separated values
    Source_Contribution:
    Global Navigation Satellite System (GNSS) survey data collected within the field-of-view of the camera used to estimate positional accuracy and generate a topo-bathymetric surface.
  2. How were the data generated, processed, and modified?
    Date: 18-Sep-2021 (process 1 of 5)
    To utilize the CoastCam imagery to make quantitative measurements, such as wave runup, both intrinsic orientation (IO) and extrinsic orientation (EO) calibration data is needed. Please refer to the dunex_c1_20210914_IO.zip and dunex_c1_20210918_EO.zip files and the dunex_c1_calibration_metadata record included in Brown and others (2024) for access to the IO and EO calibration data and more information on the calibration process. After the IO calibration was complete, the cameras were mounted on towers within the dunes at USFWS PINWR on 20210918. The cameras were connected to a control computer, powered by a solar panel and battery, and had a wireless network card. The control computer was connected to a hard drive to transfer the images upon collection. Person who carried out this activity:
    Jenna A. Brown
    U.S. Geological Survey
    600 4th Street South
    St. Petersburg, FL
    US

    (727)-502-8000 (voice)
    jenniferbrown@usgs.gov
    Data sources used in this process:
    • dunex_c1_20210914_IO
    • dunex_c1_20210918_EO
    Date: 18-Oct-2024 (process 2 of 5)
    Due to data storage limitations and closer proximity to the shoreline, timestacks were preferably created using camera 1 (c1). However, if the view was obscured in c1, then camera 2 (c2) was used instead. There were 26 instances when timestacks were collected by both cameras simultaneously at the beginning of the experiment. The selected camera was programmed to collect three-band (RGB) images at 2 Hertz (Hz) for a total of 17 minutes (2040 images), every hour during daylight hours. The images from c1 included in this data release were collected from September 18, 2021, to October 18, 2021. Each hour the camera was activated, a timestack image product was produced by sampling intensity values at a single transect of pixels, defined by (U,V) pixel coordinates, from the 2040 images and saved in Tag Image File Format (.tiff). The (U,V) sampling locations were determined by identifying a cross-shore transect of locations in a local horizontal (X,Y) coordinate system, which aligned perpendicular to the local shoreline orientation. The elevation of samples was chosen as Z = 0 m NAVD88, which is an elevation assumed to be near the water line. XYZ-sampling locations were projected into (U,V) image coordinates following established methods (Bruder and Brodie, 2020; Palmsten and Brodie, 2022) and using the camera calibration information (Brown and others, 2024). To create the timestacks, the raw images were saved on the control computer s hard drive, then processed locally to produce one timestack per hour. Person who carried out this activity:
    Jenna A. Brown
    U.S. Geological Survey
    600 4th Street South
    St. Petersburg, FL
    US

    (727)-502-8000 (voice)
    jenniferbrown@usgs.gov
    Data sources produced in this process:
    • TIFF timestack
    Date: 27-Jun-2024 (process 3 of 5)
    Because pixels were stored assuming an elevation of Z = 0 m and the true beach surface may vary, an additional processing step was needed to project the sampling locations onto a topographic-bathymetric surface representative of the beach at the time of the image data collection following previously described methods (Holland and others, 1997; Palmsten and Brodie, 2022). The topographic-bathymetric surface was developed from GNSS survey data collected within the field of view of the camera (Over and others, 2022). The point data were interpolated onto a grid using a scattered interpolation method. The local (X,Y) coordinates were rotated and translated into UTM coordinates using information describing the local origin and rotation angle for the DUNEX site, where the horizontal reference frame (X,Y) was NAD83(2011)/UTM Zone 18N. The (X,Y) coordinates were also translated from UTM to WGS84 latitude and longitude coordinates using the UTM Python library version 0.7.0. Person who carried out this activity:
    Eric Swanson
    Cherokee Nation System Solutions contracted to the U.S. Geological Survey, St. Petersburg Coastal and Marine Science Center
    600 4th Street South
    St. Petersburg, FL
    USA

    727-502-8000 (voice)
    eswanson@contractor.usgs.gov
    Data sources used in this process:
    • GNSS survey data
    Date: 27-Jun-2024 (process 4 of 5)
    A netCDF (.nc) file was created for each timestack image using the netCDF4 Python library version 1.6.4. Each netCDF file includes the timestack image; the sampling locations in (1) UV image coordinates, (2) XY UTM coordinates, (3) XY local coordinates, and (4) latitude and longitude coordinates; the Z-elevation coordinates projected onto the beach surface; and the times of collection. The timestack image was stored as a three-dimensional array of RGB pixel intensity values. The sampling locations were stored as two-dimensional arrays. The Z-elevation coordinates were stored as a one-dimensional array. The times of the collection, sampled at 2 Hz, were stored as a one-dimensional array, where each index of the array contained a time represented as epoch time, seconds elapsed since 00:00:00 UTC on January 1, 1970. Additional metadata was included in the netCDF files as global and variable attributes using the Climate and Forecast (CF)-compliant metadata convention (version CF-1.6). These attributes describe the data collection, as well as how the different coordinate systems are used within the data. Person who carried out this activity:
    Eric Swanson
    Cherokee Nation System Solutions contracted to the U.S. Geological Survey, St. Petersburg Coastal and Marine Science Center
    600 4th Street South
    St. Petersburg, FL
    USA

    727-502-8000 (voice)
    eswanson@contractor.usgs.gov
    Data sources produced in this process:
    • netCDF timestack
    Date: 27-Jun-2024 (process 5 of 5)
    A total of 411 netCDF timestack files (190 for c1, 221 for c2) are included in this release and can be viewed and downloaded on the data release webpage via the zip files. The netCDF files all use the same format in their filenames. This format has ten period-separated elements. They are as follows: 1) the start time of the timestack collection in epoch time format--seconds elapsed since 00:00:00 UTC on January 1 1970, 2) the day of the week the timestack was collected, abbreviated to three letters, 3) the month the timestack was collected, abbreviated to three letters, 4) the date and time when the timestack was collected in the format dd_hh_mm_ss where 'dd' is the day of the month, 'hh' is the hour in 24-hour format, 'mm' is the minute, and 'ss' is the second, 5) the time zone for date previously described, 6) the year the timestack was collected, 7) the site nickname where the timestack was collected, 8) the camera the timestack was collected from, either c1 or c2, 9) the name of the transect sampled to create the timestack (e.g., runup250 indicates cross-shore wave runup timestack collected at a location 250 m alongshore from the camera), and 10) the file extension, .nc. An example of a filename formatted in this way is 1631966400.Sat.Sep.18_12_00_00.GMT.2021.dunex.c1.runup250.nc. Person who carried out this activity:
    USGS SPCMSC Data Management Group
    U.S. Geological Survey - St. Petersburg Coastal and Marine Science Center
    600 4th Street South
    St. Petersburg, FL
    USA

    727-502-8000 (voice)
    gs-g-spcmsc_data_inquiries@usgs.gov
    Data sources produced in this process:
    • *.nc
  3. What similar or related data should the user be aware of?
    Bruder, Brittany L., and Brodie, Katherine L., 20200909, CIRN Quantitative Coastal Imaging Toolbox: SoftwareX Volume 12, 100582, Elsevier, Online.

    Online Links:

    Holland, K. Todd, Holman, Robert A., Lippmann, Tom C., Stanley, John, and Plant, Nathaniel, 1997, Practical use of video imagery in nearshore oceanographic field studies: IEEE Journal of Oceanic Engineering Volume 22, Issue 1, Elsevier, Online.

    Online Links:

    Palmsten, Margaret L., and Brodie, Katherine L., 20220118, The Coastal Imaging Research Network (CIRN): Remote Sensing Volume 14, Issues 3, MDPI, Online.

    Online Links:

How reliable are the data; what problems remain in the data set?

  1. How well have the observations been checked?
    The video camera collected 12.3-megapixel images. Images may be obscured by water droplets, insects, birds, salt, sand and dirt, poor visibility from adverse weather conditions or sun glare, and thus may not reflect the true state of the beach and ocean.
  2. How accurate are the geographic locations?
    The horizontal accuracy of the camera's external orientation was verified using data collected in field activity 2021-340-FA and processed with the CIRN Quantitative Coastal Imaging Toolbox (Bruder and Brodie, 2020). An extrinsic calibration survey for c1 was performed at the DUNEX site on September 18, 2021. Horizontal accuracy was obtained by comparing the ground control points from the extrinsic calibration surveys in Over and others (2022) to user selected ground control points in the camera images. For the September 18, 2021, survey: the absolute mean x error is 0.16 meters, and the absolute mean y error is 0.52 meters. Please refer to the dunex_c1_20210918_EO.zip file and the dunex_c1_calibration_metadata record included in Brown and others (2024) for more information. Horizontal coordinates are referenced to the North American Datum of 1983 (National Spatial Reference System 2011) Universal Transverse Mercator Zone 18 North (NAD83(2011)/UTM Zone 18N) coordinate system. Additionally, coordinates in the local coordinate system, as well as latitude and longitude (NAD83), are included.
  3. How accurate are the heights or depths?
    The vertical accuracy of the camera's external orientation was verified using data collected in field activity 2021-340-FA and processed with the CIRN Quantitative Coastal Imaging Toolbox (Bruder and Brodie, 2020). Please refer to the dunex_c1_20210918_EO.zip file and the dunex_c1_calibration_metadata record included in Brown and others (2024) for more information. Vertical positions are referenced to the North American Vertical Datum of 1988 (NAVD88) coordinate system.
  4. Where are the gaps in the data? What is missing?
    The imagery represents a fixed location within the U.S. Fish and Wildlife Service Pea Island National Wildlife Refuge on the Outer Banks of North Carolina. Images may not be available every hour of operation due to camera malfunction. Images may be obscured by water droplets, insects, birds, salt, sand and dirt, poor visibility from adverse weather conditions or sun glare, and thus may not reflect the true state of the beach and ocean. Depending on the conditions, one camera (c1 or c2) was used to create hourly timestacks. There were 26 instances when timestacks were collected by both cameras simultaneously at the beginning of the experiment. This product is considered complete for the information presented, as described in the abstract. 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?
    Due to data storage limitations and closer proximity to the shoreline, timestacks were preferably created using camera 1 (c1). However, if the view was obscured in c1, then camera 2 (c2) was used instead. There were 26 instances when timestacks were collected by both cameras simultaneously at the beginning of the experiment. The selected camera was programmed to collect three-band images every hour during daylight hours and take video for approximately 17 minutes. A timestack image for the 17-minute period was created by sampling a single transect on the beach.

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.
  1. Who distributes the data set? (Distributor 1 of 1)
    USGS SPCMSC Data Management Group
    U.S. Geological Survey - St. Petersburg Coastal and Marine Science Center
    600 4th Street South
    St. Petersburg, Florida
    USA

    727-502-8000 (voice)
    gs-g-spcmsc_data_inquiries@usgs.gov
  2. What's the catalog number I need to order this data set? *.nc
  3. What legal disclaimers am I supposed to read?
    This digital publication was prepared by an agency of the United States Government. Although these data have been processed successfully on a computer system at the U.S. Geological Survey, no warranty expressed or implied is made regarding the display or utility of the data on any other system, nor shall the act of distribution imply any such warranty. The U.S. Geological Survey shall not be held liable for improper or incorrect use of the data described and (or) contained herein. Reference herein to any specific commercial product, process, or service by trade name, trademark, manufacturer, or otherwise does not constitute or imply its endorsement, recommendation, or favoring by the United States Government or any agency thereof.
  4. How can I download or order the data?
    • Availability in digital form:
      Data format: The data download file is compressed and must be unzipped using software such as WinZip, 7zip, Peazip or pkUnzip before use. in format netCDF (version 4.3) *.nc is a netCDF file that contains timestack imagery; elevations, in meters; and, coordinate information, in Easting and Northing UTM coordinates and local grid coordinates, measured in meters, and longitude and latitude coordinates in degrees. The netCDF files can be downloaded in the zip files listed in the Network_Resource_Name link below.
      Network links: https://coastal.er.usgs.gov/data-release/doi-P14EWDST/data/dunex_c1_2021_timestacks.zip
    • Cost to order the data: None

Who wrote the metadata?

Dates:
Last modified: 15-Aug-2024
Metadata author:
USGS SPCMSC Data Management Group
U.S. Geological Survey, St. Petersburg Coastal and Marine Science Center
600 4th Street South
Saint Petersburg, FL

727-502-8000 (voice)
gs-g-spcmsc_data_inquiries@usgs.gov
Metadata standard:
Content Standard for Digital Geospatial Metadata (FGDC-STD-001-1998)
This page is <https://cmgds.marine.usgs.gov/catalog/spcmsc/dunex_c1_timestacks_metadata.faq.html>
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