Christine J. Kranenburg
Andrew C. Ritchie
Jenna A. Brown
Jin-Si R. Over
Christopher R. Sherwood
Jonathan A. Warrick
Phillipe A. Wernette
20211015
Aerial Imagery of the North Carolina Coast: 2019-08-30 and 2019-09-02, Pre-Hurricane Dorian
remote-sensing image
Christine J. Kranenburg
Andrew C. Ritchie
Jenna A. Brown
Jin-Si R. Over
Christopher R. Sherwood
Jonathan A. Warrick
Phillipe A. Wernette
20210930
Aerial Imagery of the North Carolina Coast: 2019-08-30 and 2019-09-02, Pre-Hurricane Dorian
U.S. Geological Survey Data Release
DOI:10.5066/P9WR0VB1
St. Petersburg, Florida
U.S. Geological Survey - St. Petersburg Coastal and Marine Science Center
https://doi.org/10.5066/P9WR0VB1
The U.S. Geological Survey (USGS) Remote Sensing Coastal Change (RSCC) project collects aerial imagery along coastal swaths, in response to storm events, with optimized endlap/sidelap and precise position information to create high-resolution orthomosaics, three-dimensional (3D) point clouds, and digital elevation/surface models (DEMs/DSMs) using Structure-from-Motion (SfM) photogrammetry methods. These products are valuable for measuring topographic and landscape change, and for understanding coastal vulnerability and response to disturbance events.
A nadir (vertical) aerial imagery survey was conducted from Cape Lookout, North Carolina to the Virginia-North Carolina border on August 30th and September 2, 2019, to document pre-storm conditions in preparation for the passing of Hurricane Dorian (U.S. landfall was on September 6). The observations along the coastline cover an approximately 275-kilometer (km) long by 300 to 700-meter (m) wide swath of coastline and encompass both highly developed towns as well as natural undeveloped areas, including the federal lands of Cape Lookout National Seashore and Cape Hatteras National Seashore. Low altitude (300 meters above ground level) digital aerial imagery were acquired from a manned, fixed-wing aircraft using a Sony A7R 36 Megapixel digital camera, along with precise aircraft navigation Global Navigation Satellite System (GNSS) data. Data were collected in shore-parallel lines, flying at approximately 50 meters per second (m/s) and capturing true color imagery at 1 Hertz (Hz), resulting in image footprints with approximately 75-80% endlap, 60-70% sidelap, and a 5.3-centimeter (cm) ground sample distance (GSD). The precise time of each image capture (flash event) was recorded, and the corresponding aircraft position was computed during post-processing of the GNSS data; precise image positions can then be determined by accounting for the lever arm offsets between the aircraft GNSS antenna and the camera lens. Position data, provided as latitude/longitude/ellipsoid height, is referenced to the North American Datum of 1983 (NAD83(2011)).
These 24,072 aerial images were collected over two non-consecutive days along the coast of the Outer Banks, North Carolina, with sufficient resolution and endlap/sidelap to produce Structure-from-Motion (SfM) photogrammetry products to observe the baseline conditions of the coast before any impacts due to Hurricane Dorian.
These data were collected by the USGS Coastal and Marine Hazards and Resources Program under the USGS field activity number (FAN) 2019-310-CNT, and the associated field activity web page contains additional information regarding the field activity: https://cmgds.marine.usgs.gov/fan_info.php?fan=2019-310-CNT.
To guarantee coverage of the entire survey area with good lighting conditions, aerial imagery was collected over multiple days; acquisition was timed to coincide with low tide along the beach areas to ensure the maximum shoreline extent was captured. Bounding coordinates for the aerial survey are derived from the overall flight path and are not necessarily representative of the imagery coverage.
20190830
20190902
ground condition
None planned
-76.53790806
-75.45995754
36.56366152
34.56445526
USGS Metadata Identifier
USGS:28df83a6-d46e-4cae-b000-59e7fc977db6
USGS Thesaurus
structure from motion
remote sensing
aerial photography
image collections
geospatial datasets
coastal processes
geomorphology
hurricanes
None
U.S. Geological Survey
USGS
Coastal and Marine Hazards and Resources Program
CMHRP
aerial imagery
ISO 19115 Topic Category
geoscientificInformation
imageryBaseMapsEarthCover
oceans
Geographic Names Information Service (GNIS)
North Carolina
Outer Banks
Cape Hatteras National Seashore
Cape Lookout National Seashore
Albemarle Sound
Pamlico Sound
Nags Head
None
August 2019
September 2019
Pre-Hurricane Dorian
none
USGS-authored or produced data and information are in the public domain from the U.S. Government and are freely redistributable with proper metadata and source attribution. Please recognize and acknowledge the U.S. Geological Survey as the originator of the dataset and in products derived from these data.
Christine J. Kranenburg
U.S. Geological Survey, St. Petersburg Coastal and Marine Science Center
Physical and Mailing
600 4th Street South
St. Petersburg
FL
33701
USA
727-502-8000
ckranenburg@usgs.gov
2019-08_NC_RegionalMap.jpg
Regional map (which is included in 2019-08_NC_AreaMaps.zip) of the survey area along the Outer Banks, North Carolina, of pre-Hurricane Dorian survey conducted during USGS field activity 2019-310-CNT.
JPG
2019-08_NC_Area1.jpg
This map, found within 2019-08_NC_AreaMaps.zip, shows the extent of Area 1 in the regional map for the pre-Hurricane Dorian aerial images from Cape Lookout, North Carolina, to Hatteras Inlet, North Carolina. The flight paths were divided into 3-minute latitudinal segments, represented by alternating purple and orange lines, and images for each segment are contained in zip files named according to the four-digit latitude (degree/minute) of the southern boundary. Some segments are further divided to limit the zip files to 20 GB and are identified by labels (a-b); all portions of a segment must be downloaded to ensure full coverage.
JPG
2019-08_NC_Area2.jpg
This map, found within 2019-08_NC_AreaMaps.zip, shows the extent of Area 2 in the regional map for the pre-Hurricane Dorian aerial images from Hatteras Inlet, North Carolina, to Nags Head, North Carolina. The flight paths were divided into 3-minute latitudinal segments, represented by alternating purple and orange lines, and images for each segment are contained in zip files named according to the four-digit latitude (degree/minute) of the southern boundary. Some segments are further divided to limit the zip files to 20 GB and are identified by labels (a-c); all portions of a segment must be downloaded to ensure full coverage.
JPG
2019-08_NC_Area3.jpg
This map, found within 2019-08_NC_AreaMaps.zip, shows the extent of Area 3 in the regional map for the pre-Hurricane Dorian aerial images from Nags Head, North Carolina, to the Virginia-North Carolina border. The flight paths were divided into 3-minute latitudinal segments, represented by alternating purple and orange lines, and images for each segment are contained in zip files named according to the four-digit latitude (degree/minute) of the southern boundary.
JPG
Data collection was funded by the U.S. Geological Survey. The authors would like to thank pilot Wayne Wright of C.W. Wright Consulting for data acquisition and systems expertise.
Hinck, J.E.
Stachyra, J.
2019
2019 Disaster Relief Act—USGS recovery activities
U.S. Geological Survey Fact Sheet
2021-3066
https://doi.org/10.3133/fs20193066
Westoby, M.J.
Brasington, J.
Glasser, N.F.
Hambrey, M.J.
Reynolds, J.M.
2012
‘Structure-from-Motion’ photogrammetry: A low-cost, effective tool for geoscience applications
Geomorphology
vol. 179
Amsterdam, Netherlands
Elsevier
pages 300-314
https://doi.org/10.1016/j.geomorph.2012.08.021
Over, J.R.
Ritchie, A.C.
Kranenburg, C.J.
Brown, J.A.
Buscombe, D.
Noble, T.
Sherwood, C.R.
Warrick, J.A.
Wernette, P.A.
2021
Processing Coastal Imagery with Agisoft Metashape Professional Edition, Version 1.6—Structure from Motion Workflow Documentation
U.S. Geological Survey Open-File Report
2021-1039
https://doi.org/10.3133/ofr20211039
The accuracy of the position data is based on the accuracy and precision of the GNSS equipment and camera timing, number and length of baselines and atmospheric conditions.
Note that the positions in the image EXIF headers are aircraft GNSS antenna positions and are limited to six decimal places, whereas the positions in the external navigation file are accurate to ten decimal places and are therefore highly recommended for use in SfM processing to produce the highest quality derived products.
All data fall within expected ranges.
This dataset is considered complete for the information presented, as described in the abstract. Users are advised to read the entire metadata record carefully for additional details.
Positions provided in the aircraft navigation file (2019-08_NC_AircraftPositions.txt) have an estimated 2-sigma horizontal accuracy of 10 cm. The accuracy of the positions in the image EXIF headers are reduced due to field size limitations for storing latitude/longitude.
Positions provided in the aircraft navigation file (2019-08_NC_AircraftPositions.txt) have an estimated 2-sigma vertical accuracy of 15 cm.
IMAGE ACQUISITION
C. W. Wright Consulting used a Sony A7R 36 Megapixel digital camera aboard a Piper P28A aircraft to conduct a nadir (vertical) aerial imagery survey from Cape Lookout, North Carolina, to the Virginia-North Carolina border on August 30th and September 2nd, 2019, to document pre-storm conditions in preparation for the passing of Hurricane Dorian. Data were collected to facilitate SfM processing (Westoby and others, 2012) in shore-parallel lines, flying at approximately 50 m/s and capturing true color imagery at 1 Hz, resulting in image footprints with approximately 75-80% endlap, 60-70% sidelap, and 5.3-cm GSD. A total of 24,072 raw (ARW) images, raw dual-frequency carrier phase GNSS data and photo event time data were delivered to the USGS St. Petersburg Coastal and Marine Science Center.
20190902
Christine J. Kranenburg
U.S. Geological Survey, St. Petersburg Coastal and Marine Science Center
Cartographer
Physical and Mailing
600 4th Street South
St. Petersburg
FL
33701
USA
727-502-8000
ckranenburg@usgs.gov
AIRCRAFT NAVIGATION PROCESSING
Raw GNSS data received by the antenna mounted atop the aircraft were recorded at 1 Hz by a dual-frequency survey-grade GNSS receiver, which was post-processed and differentially corrected with no fewer than 5 continuously operating reference stations (CORS) using Novatel's GrafNav software (v. 8.80) to produce 1-Hz aircraft trajectories.
The aircraft trajectories, in combination with precisely recorded image capture (flash event) times, are used to generate aircraft GNSS antenna positions at the moment of each image capture (2019-08_NC_AircraftPositions.txt). The positions in the aircraft navigation file represent the position of the aircraft GNSS antenna, not the position of the camera or features photographed. To determine actual image positions, photogrammetric software such as Agisoft Metashape can be used to apply the lever arm offsets (in the camera frame of reference) from the GNSS antenna reference point to the camera lens, which are 0.1 m, -0.15 m, and 1.25 m, in the x, y, and z directions respectively; see Over and others (2021) for details.
20200326
Christine J. Kranenburg
U.S. Geological Survey, St. Petersburg Coastal and Marine Science Center
Cartographer
Physical and Mailing
600 4th Street South
St. Petersburg
FL
33701
USA
727-502-8000
ckranenburg@usgs.gov
IMAGE PROCESSING & SAVING
Images were received from the vendor in Sony RAW (ARW) format and converted to Joint Photographic Experts Group (JPG) format using Adobe Camera Raw (v. 12.2.1) and applying the Camera Neutral Profile. Image file names represent capture date, time stamp, and ancillary data, using the following convention: yyyy-mmdd-hhmmss-DSCnnnnn-N7251F.jpg where yyyy_mmdd represents the year (yyyy), month (mm) and day (dd) of capture; hhmmss is the time of capture as hours (hh), minutes (mm), seconds(ss) in Universal Coordinated Time (UTC); DSCnnnnn represents a sequential image ID generated by the camera; and N7251F is the tail number of the aircraft used for acquisition.
20200620
Andrew R. Ritchie
U.S. Geological Survey, Pacific Coastal and Marine Science Center
Geologist
Physical and Mailing
2885 Mission St.
Santa Cruz
CA
95060
USA
831-460-7454
aritchie@usgs.gov
IMAGE EXIF & SORTING
Georeferencing, copyright, and other relevant information was added to the EXIF header of each photo using Phil Harvey’s ExifTool (v. 11.88). To extract the information from the image headers using ExifTool, the following command can be used (tested with ExifTool version 11.88):
exiftool -csv -f -filename -GPSDateStamp -GPSTimeStamp -GPSLongitude -GPSLatitude -n -Artist -Credit -comment -keywords -Caption -Copyright -CopyrightNotice -Caption-Abstract -ImageDescription directoryname/*.jpg > out.csv
The -csv flag writes the information out in a comma-delimited format. The -n option formats the latitude and longitude as signed decimal degrees.
Images are sorted by latitude and contained within zip files according to 3-minute latitude segments of the coast (labeled based on the southern latitude boundary in degrees (DD) and minutes (mm) North (N), and further subdivided (labeled as -a/b/c) as needed to limit the overall file size.
20200820
Christine J. Kranenburg
U.S. Geological Survey, St. Petersburg Coastal and Marine Science Center
Cartographer
Physical and Mailing
600 4th Street South
St. Petersburg
FL
33701
USA
727-502-8000
ckranenburg@usgs.gov
Raster
Pixel
0.000001
0.000001
Decimal degrees
North American Datum of 1983 (2011)
GRS 1980
6378137.000000
298.257223563
2019-08_NC_AircraftPositions.txt (2019-08_NC_AircraftPositions.zip)
The tab-separated American Standard Code for Information Interchange (ASCII) text file, 2019-08_NC_AircraftPositions.txt, is included within 2019-08-NC_AircraftPositions.zip and contains the post-processed aircraft navigation GNSS data (position of the GNSS antenna at the moment of each image capture).
USGS
ImageName
File names of individual aerial images; see the Lineage section and IMAGE PROCESSING & SAVING Process_Description for file naming convention details.
USGS
2019-0830-162419-DSC05908-N7251F.jpg
2019-0902-204425-DSC04710-N7251F.jpg
Latitude
Latitude of aircraft GNSS antenna position at the moment of each image capture, in decimal degrees (NAD83(2011)).
USGS
34.56445526
36.56366152
meters
Longitude
Longitude of aircraft GNSS antenna position at the moment of each image capture, in decimal degrees (NAD83(2011)).
USGS
-75.45995754
-76.53790806
meters
Altitude
Altitude of aircraft GNSS antenna position at the moment of each image capture, in meters above the NAD83 ellipsoid.
USGS
89.191
318.377
meters
Aerial Imagery (2019-08_NC_DDmmN-a/b/c.zip) – Individual aerial images are available in JPG format and are contained within ZIP files; see the Lineage section and IMAGE EXIF & SORTING Process_Step for more information on file naming and image sorting conventions.
Aircraft Position Data (2019-08_NC_AircraftPositions.zip) – The ZIP file contains a text (TXT) file of the precise post-processed GNSS position of the aircraft at the precise flash event time of each image; see the Entity_and_Attribute_Information section and Detailed_Description for more information on the variables reported in the TXT file, and see the Lineage section and AIRCRAFT NAVIGATION PROCESSING Process_Step for information on how to compute the precise image positions from the aircraft positions using photogrammetric software and applying lever arm offsets between the aircraft GNSS antenna and camera lens.
Area Maps (2019-08_NC_AreaMaps.zip) - The ZIP file contains a regional map and detailed area maps, available in JPG format, of individual coastline segments corresponding to the aerial imagery ZIP files within each survey subset area; see the Identification_Information section and Browse_Graphic text for additional information about the maps.
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.
SPCMSC Data Management Group
U.S. Geological Survey, St. Petersburg Coastal and Marine Science Center
Physical and Mailing
600 4th St South
St. Petersburg
FL
33701
USA
727-502-8000
gs-g-spcmsc_data_inquiries@usgs.gov
This publication was prepared by an agency of the United States Government. Although these data were 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.
JPEG
JPEG images can be opened directly with any JPEG-compatible image viewer.
https://coastal.er.usgs.gov/data-release/doi-P9WR0VB1/
Aerial imagery, available in JPG format, can be downloaded per segment of coastline as zipped files from the data table of the data release landing page, which is accessed via the Network_Resource_Name link. The following link (https://coastal.er.usgs.gov/data-release/doi-P9WR0VB1/data/2019-08_NC_DDmmN-a/b/c.zip) can be modified and used to directly obtain the data files: where DDmmN represents the southern boundary of the 3-degree latitude segment in degrees (DD) and minutes (mm) North (N), and the labels -a/b/c are used to further subdivide the segment as needed to limit the overall file sizes.
tab-delimited text
TXT files can be opened directly with any text-editing software.
https://coastal.er.usgs.gov/data-release/doi-P9WR0VB1/data/2019-08_NC_AircraftPositions.zip
Aircraft navigation data, available in TXT format, can be downloaded as a ZIP file from the Network_Resource_Name link.
JPEG
JPEG images can be opened directly with any JPEG-compatible image viewer.
https://coastal.er.usgs.gov/data-release/doi-P9WR0VB1/data/2019-08_NC_AreaMaps.zip
A regional scale and detailed area maps, available in JPG format, can be downloaded as a ZIP file from the Network_Resource_Name link.
None.
20210930
Christine J. Kranenburg
U.S. Geological Survey, St. Petersburg Coastal and Marine Science Center
Cartographer
Physical and Mailing
600 4th Street South
St. Petersburg
FL
33701
USA
727-502-8000
ckranenburg@usgs.gov
Content Standard for Digital Geospatial Metadata
FGDC-STD-001-1998