Low-altitude visible, multispectral, and thermal-infrared imagery from edge-of-field monitoring sites for Great Lakes Restoration Initiative - Michigan Flume 2

These orthophotos and digital surface model (DSM) were derived from low-altitude (approximately 92-m above ground surface) images collected from Unmanned Aerial System (UAS) flights over edge-of-field sites that are part of U.S. Geological Survey (USGS) Great Lakes Restoration Initiative (GLRI) monitoring. The objective of this UAS photogrammetry data collection was to provide information on the tile-drain network in individual fields with the goal of understanding already observed patterns in runoff amount and water quality from these sites. A 3DR Solo quadcopter served as the flight vehicle, flights were pre-planned using Mission Planner, and flights were flown using Tower. Geospatial data were originally in WGS84 and projected to a local coordinate system for each site. Visible color (Vis-C) imagery was collected with a Ricoh GRII as a single band. Multispectral (MS) imagery was collected with a MicaSense RedEdge 3 as five co-located bands: blue (B; approximately 475-500 nanometers [nm]), green (G; 550-560 nm), red (R; 660-670 nm), red-edge (710-720 nm), and near infrared (NIR; 820-860 nm). Thermal-infrared (TIR) data were collected using a FLIR Vue Pro R 640 camera with an uncooled vanadium oxide microbolometer and a 13-mm lens. Images were collected at 2-second intervals, with a flight speed of 9 meters per second (m/s), 7 m/s, or 5 m/s (visible, multispectral, thermal, respectively) with approximately 75% overlap between sequential images and 70% sidelap between adjacent flight lines. Cameras used local time for visible and thermal imagery collection but Coordinated Universal Time (UTC) for multispectral imagery collection. Photogrammetry to integrate the individual images into an orthophoto and digital surface model (for visible imagery) was done using Agisoft Metashape.