| Description |
The U.S. Geological Survey (USGS) Remote Sensing Coastal Change (RSCC) project collects aerial imagery along coastal swaths 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 Honeymoon Island to Naples, Florida on September 6 and 7, 2023, to document post-storm conditions after the passage of Hurricane Idalia on August 30, 2023. The observations along the coastline cover an approximately 275-kilometer-long by 300 to 700-meter-wide swath of coastline and encompass impacted areas including both highly developed towns, such as Captiva Island, Sanibel Island, and Fort Myers Beach, as well as natural, undeveloped areas, including Cayo Costa and Lovers Key State Beaches. Low altitude (300 meters above ground level) digital aerial imagery were acquired with a manned, fixed-wing aircraft using the "Precision Airborne Camera (PAC)" System (version 2). The PAC system is operated by C.W. Wright and consists of a mounted fixed-lens digital camera, along with a custom integrated survey-grade Global Navigation Satellite System (GNSS) receiver. 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, which are provided in the PAC System metadata (Kranenburg and others, 2023, https://cmgds.marine.usgs.gov/data-services/rscc/PrecisionAirborneCameraSystem). Position data, provided as latitude/longitude/ellipsoid height, is referenced to the North American Datum of 1983 National Spatial Reference System 2011 (NAD83(2011)) coordinate system. [More]
|
