Time Series of Structure-from-Motion Products-Orthomosaics, Digital Elevation Models and Point Clouds: Little Dauphin Island and Pelican Island, Alabama, September 2018-April 2019

Barrier islands are dynamic environments that are gradually shaped by currents, waves, and tides under quiescent conditions, yet can evolve in the time scale of hours to days during hurricanes and other extreme storms. Small unmanned aircraft systems (sUAS) allow the opportunity for collecting topographic data for monitoring purposes, with a temporal resolution that is well-suited for these dynamic environments. Aerial imagery acquired with sUAS, in conjunction with surveyed ground control points (GCP) visible in the imagery, can be processed with structure-from-motion (SfM) photogrammetry techniques to produce three-dimensional (3D) point clouds, digital elevation models (DEMs) and high-resolution orthomosaics. This dataset, consisting of SfM products, prepared by the U.S. Geological Survey (USGS) St. Petersburg Coastal and Marine Science Center (SPCMSC), was collected as part of the Coastal Resource Evaluation for Management Application (CREMA) project; which were then used to produce vegetation and habitat maps, explore vegetation bias correction techniques for SfM elevation models, and combined with shorebird surveys to understand and predict how shorebirds utilize barrier island habitats.

Low altitude (60 meters above ground level) nadir imagery was collected using a Ricoh GR II camera and MicaSense RedEdge 3 multispectral camera aboard a 3DR Solo sUAS over Pelican Island and/or the northern half of Little Dauphin Island on an approximately monthly interval between September 2018 and April 2019. Pelican Island was surveyed 5 times and Little Dauphin Island was surveyed twice during this time period. Photogrammetry software was used to create SfM products from the imagery. All horizontal data is given in Universal Transverse Mercator (UTM) projected coordinate system, Zone 16 North (16N), referenced to the North American Datum of 1983 (NAD83 (2011)), and elevation is referenced to the North American Vertical Datum of 1988 (NAVD88), GEOID12B.