2022-334-FA_BocaChica_Polecam_Imagery: High-resolution Geophysical and Imagery Data Collected in November 2022 Offshore of Boca Chica Key, FL

IMAGE ACQUISITION: Images were collected as .tif files by the USGS Polecam system, which was mounted to the USGS vessel R/V Sallenger and transited at a speed of approximately 3 knots during USGS field activity 2022-334-FA. Imagery was acquired from November 12-13, 2022, using the Marfac Machine Vision Camera Interface Software, which was developed by USGS scientists (Hatcher, 2021). The image-collection frequency was 1 Hz, and GNSS positions were recorded at 10 Hz. Aperture and shutter speed were consistent for each group of images at a study site. Image files were named programmatically during collection with the USGS field activity number, 2022-334-FA, location of field work, a 14-digit UTC date-time value formatted as yyyymmddhhmmss, thousandths of seconds, and the sequential image number for that camera. For example, '2022-334-FA_BocaChica-20221112173133_400-1.tif' indicates field activity 2022-334-FA, the study site at Boca Chica, November 12, 2022, 17:31:33.400 (UTC), and camera image 1 of the series.

POLECAM NAVIGATION PROCESSING: Raw GNSS data received by a Spectra SP90 Receiver and Trimble Zephyr GNSS Antenna mounted on top of the Polecam were recorded at 10 Hz. The GNSS data were post-processed and differentially corrected against the Key West, Florida, (FLKW) continuously operating reference station (CORS) in NovAtel's GrafNav software. Horizontal coordinates were referenced to the North American Datum of 1983 (National Spatial Reference System 2011) coordinate system. The positions in the Polecam navigation file represent the post-processed position of the GNSS antenna reference point (ARP), which was located vertically above the camera. Neither elevation nor bathymetric data were collected using the GNSS antenna. The following offset values for the camera were calculated for x,y,z in units of meters. 0 m(x), 0 m(y), and 1.84 m(z). The approximate 1.84-m vertical offset between the antenna and the Polecam instrument were not accounted for during acquisition, nor have the post-processed navigation files been corrected to reflect the offset.

Conversion of Images to .JPEG The images acquired with the camera were converted from TIF format to JPEG format using ImageMagick using the following command: 'magick mogrify -format .jpg *.tif'.

IMAGERY HEADERS: The images acquired with the camera were geotagged and processed to add additional information required by the USGS to the exchangeable image file format (EXIF) and other imagery headers using Phil Harvey's ExifTool. The images were given EXIF header information in the directory with all the photos by assigning all the tags in a text file to each photo using ExifTool. Adding headers also required a .csv file containing tags of the image name, GPSDateTime, GPSLatitude, and GPSLongitude. The following describes the dictionary object in the text file with each entry in the dictionary being a tag-value pair: tags = {'Copyright': 'Public Domain', 'CopyrightNotice': 'Public Domain - please credit U.S. Geological Survey', 'Artist': 'USGS SPCMSC', 'Make': 'TELEDYNE FLIR', 'Model': 'BFS-PGE-122S6C-C', 'GPSMapDatum': 'EPSG:6318 NAD83 (2011) ', 'GPSLatitudeRef': 'N', 'GPSLongitudeRef': 'W', 'Credit': 'U.S. Geological Survey', 'Contact': 'gs-g-spcmsc_data_inquiries@usgs.gov', '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", 'AttributionURL': 'https://doi.org/10.5066/P9KNCMFY', 'XMP-photoshop:Credit': 'U.S. Geological Survey', 'iptcCore:CreatorWorkEmail': 'gs-g-spcmsc_data_inquiries@usgs.gov', 'Rights': 'Public Domain', 'ImageDescription': 'https://cmgds.marine.usgs.gov/fan_info.php?fan=2022-334-FA; Photograph of seabed collected at Boca Chica Key, FL Keys, collected in November 2022 during USGS field activity 2022-334-FA', 'Description': 'https://cmgds.marine.usgs.gov/fan_info.php?fan=2022-334-FA; Photograph of seabed collected at Boca Chica Key, FL Keys, collected in November 2022 during USGS field activity 2022-334-FA', 'Comment': 'Photograph of seabed collected at Boca Chica Key, FL Keys, collected in November 2022 during field activity 2022-334-FA', 'Keywords': 'coral reef, Remote Sensing, Boca Chica Key, Florida', 'ExternalMetadataLink': 'https://www1.usgs.gov/pir/api/identifiers/USGS:8fa37f5c-dd94-4f14-910e-860c5615b09d'}. All of the previously listed tags were the same for each image. Additionally, there were tags added to the dictionary object that would have a different value for each image depending on factors such as the image location and date and time when the image was captured. These tags and an example value are included as follows, as well as a description for why the values differ, as needed: 'GPSLatitude': '24.5528', 'GPSLongitude': '-81.6937', 'DateTimeOriginal': 2022:11:12 17:31:34; Tags were added to each image by using the command: 'exiftool -@ text_file_dictionary.txt -csv=images_date_location.csv *.jpg'. To read out the imagery header information to a comma-separated values (CSV) file the command is: 'exiftool -csv *.jpg > allheaders.csv'. Specific tags may be specified with this command, if preferred .

A total of 23,948 JPEG images are included in this release (2022_334-FA_polecam_images) and can be viewed and downloaded on the Imagery Data System (IDS), https://cmgds.marine.usgs.gov/idsviewer/data_release/10.5066-P9KNCMFY. The images on the IDS are sorted by default from newest to oldest date-time collected.