The U.S. Geological Survey collected low-altitude airborne natural color imagery via a fixed-wing uncrewed aircraft system (UAS) for mapping channel and vegetation change along a 6-mile reach of the Middle Green River at Ouray National Wildlife Refuge near Ouray, Utah. Visual imagery was collected in jpg format and Structure-from-Motion (SfM) photogrammetry techniques were applied (Over et al., 2021) using Agisoft Metashape Professional (v. 2.3.0 build 21954) to derive time-specific high-resolution 5 centimeter natural color orthomosaics of the study reach annually from 2024 to 2025. Ground control points (4feet x 4feet ground targets) were also surveyed in the field using Trimble RTK GPS survey units and were used in georectification in the SfM process.
