Using UAVs and Remote Sensing Techniques to Measure Reclamation Success

The goal of the UAS (Unmanned Aerial Systems) reclamation monitoring program in 2015 was to gather, evaluate, and analyze airborne collected data from reclaimed areas and further development of vegetation measurement and reclamation materials stockpile volumes using an innovative approach and technology. The existing capability of UAS to provide very high resolution imagery will be used, and new sensors will be evaluated: LiDAR and VHIR. Specific project objectives were to (1) use Unmanned Aerial Systems (UAS) to capture very high resolution data using three different sensors in visible, Near-Infrared and LiDAR; (2) generate very high resolution (2.5cm pixel) aerial imagery and elevation data, and (3) develop an advanced spatial analysis technique to measure and monitor vegetation growth in natural and reclamation areas and calculate Reclamation Material Stockpile (RMS) volumes.

Data was collected with the PrecisionHawk’s Lancaster UAS at three sites, processed into 2D and 3D mapping products, and analyzed for positional accuracy and the ability to identify and measure replanted and natural tree canopy. UAS was shown to offer a safe and accurate way to collect very high resolution imagery of remote areas. The proposed monitoring and analysis system made it possible to identify trees of various heights and sizes. Accuracy of tree canopy classification was between 80% and 90% based on comparison with ground observations. However, estimates of tree height were often inaccurate: trees <1 m tall were typically underestimated while trees> 1 m tall were typically overestimated. Airborne LiDAR was collected, but use of a single band GPS unit made it impossible to obtain accurate post-processing results. Hardware, firmware, and processing advances will improve the capabilities of UAS LiDAR analysis and should prove useful for obtaining better estimates of height.