Low-altitude aerial imagery collected from a helium powered balloon-kite at Marconi Beach, Wellfleet during field activity 2021-022-FA on March 17, 2021

These JPEG images were collected with a camera (Ricoh GRII HD) labeled 'r##', where 'r' indicates a Ricoh camera, and the following 2 digits normally indicate the camera ID. The camera was wired to the GNSS receiver and duct taped together, then hung from the Helikite (2021022FA_Marconi_HelikiteCameraAttachment_browse.JPG) so that the camera faces downward. The Helikite was on a 50meter string and kitesurfing harness; together the Helikite and gear was walked down the beach. Horizontal positions and elevations of each image (2021022FA_Marconi_f1_photolocations.csv) were recorded from an GNSS receiver (EMLID Reach M2), which were processed in PPK mode using the MASS CORS network. The navigation data is added to the image EXIF information after the flight as described in the process steps. It is recommended when using the imagery for photogrammetric purposes to also use the Aeropoint locations (see larger work citation Navigation: 2021022FA_Marconi_nav_AeroPoints.csv) as ground control points.

The GNSS navigation data was processed in Inertial Explorer (https://novatel.com/products/waypoint-software/inertial-explorer, version 8.70.8722). In the software, the data were processed using an 'Antenna Height' of 0.0 m to indicate that there was no offset from the GPS to the camera. The positions were processed in the NAD83(2011) datum, providing the Latitude, Longitude, and H_Ell_m attributes and then Geoid 12B was applied using NAVD88 as the vertical datum and UTM Zone 19N for the horizontal coordinate reference system to produce the Northing, Easting, and H_Ortho_m attributes. All of the attributes here are provided in the 2021022FA_Marconi_f1_photolocations.csv but only the latitude, longitude, and H_Ortho_m (NAVD88) are embedded in the image header.

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. Using the GNSS navigation from the previous step, ExifTools was used to geotag each photo with the GPSDateStamp, GPSTimeStamp, GPSLatitude, GPSLongitude, and GPSAltitude stored in a csv file with the command: -geotag "C:\directory\name\Geotags.csv" -geosync=+23 C:\directory\name\of\photos Where the -geosync command tells the exiftools that the GPS and photo time are offset by 23 seconds. The TimeStamp is in UTC, the latitude and longitude geotags are in NAD83(2011) and the altitude geotag is the H_Ortho_m in NAVD88 (m). The first row of the CSV are the headers; the first column is SourceName (unique image names), and the rest of the columns are the geotags listed in Step 1. Keywords were added with the following command in the directory with all the photographs: exiftool -sep ", " -iptc:keywords="Marconi Beach, Massachusetts, 2021-022-FA, Ricoh, USGS, aerial imagery" *.JPG 2. Additional EXIF information was added in the directory with all the photos with the command: exiftool -csv=directory\name\EXIF_tags.csv *.JPG Where the CSV file has the following headings (the first column is the SourceFile with the unique photo names) and information (anything in () is format based and is only provided to give more context) -Credit="U.S. Geological Survey " -Contact="WHSC_data_contact@usgs.gov " -Copyright="Public Domain " -ImageDescription=" https://cmgds.marine.usgs.gov/data/field-activity-data/2021-022-FA/ ; Low-altitude aerial photograph of Marconi beach, Wellfleet, Massachusetts from USGS Field Activity 2021-022-FA " - XMP:UsageTerms= "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 "‚ -Attribution="https://doi.org/10.5066/P9KSG1RQ " -GPSAreaInformation="position post-processed from nearby GPS " -GPSMapDatum="ESPG: 6317 (NAD83[2011]), altitude in NAVD88 Geoid12B" -GPSDateStamp="2021:03:17 " -GPSTimeStamp="(HH:MM:SS UTC) " -GPSLatitude="(in decimal degrees) " -GPSLatitudeRef="N " -GPSLongitude="(in decimal degrees)" -GPSLongitudeRef="W " -GPSAltitude=‚" (in NAVD88 m)‚ "-Artist="Peter Traykovski (WHOI)" -OriginalFilename="M#######.JPG (where # combinations are unique) " *.JPG To read out the photo information to a csv the command is: exiftool -csv -f -filename -GPSDateStamp -GPSTimeStamp -GPSLongitude -GPSLatitude -n -Artist -Contact -Comment -Credit -Copyright -ImageDescription -OriginalFileName -AttributionURL -Event -GPSAreaInformation -GPSMapDatum *.JPG > directory/name/out.csv Fewer tags or additional tags may be taken out with this command from those written above.
3. All the JPEG images were renamed with Namexif 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 '2021022FA_f01r02_20200306T165822Z_M1040356.JPG', 2021022FA is the survey ID, f01 is the flight number, r02 is the internal camera ID, 20200306 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 M1040356.JPG is the original raw photo name appended to the end of the new filename. Because GPS data was collected in UTC and had a 23 second offset from the time produced by the camera (EST), the time in Namexif was shifted +4:00:23.