The USGS National Unmanned Aircraft Systems (UAS) Project office is assessing natural and man-made features detected by low altitude light detection and ranging (lidar) scanners with photogrammetric surveying techniques via UAS platforms. The resulting point cloud models are sets of data points in a 3D coordinate system, representing a topographic surface. By collecting overlapping photographs, the constructed point cloud models provide reliable spatial information. Lidar surveying technology measures distance to a target with a pulsed laser, providing another technique to generate a point cloud dataset. By examining cross sections over various features, USGS scientists begin to understand the strengths and weaknesses of these two data collection methods.
Two test locations, Fountain Creek, CO, and Coal Creek Canyon Open Space, CO, were selected for this comparison study. The location contained various features consisting of low to high grasses, medium to high deciduous tree cover, and hydrologic surface features. The Pulse Vapor 55 UAS helicopter platform equipped with a YellowScan LiDAR surveyor payload and a Sony a7R mirrorless interchangeable lens camera conducted the aerial surveys. The system is capable of a 40-minute flight duration, collecting the lidar scans and photogrammetric surveys simultaneously.
Point cloud model from YellowScan LiDAR surveyor onboard the Pulse Vapor 55 Unmanned Aerial System.