Comparing Unmanned Aerial Vehicle (UAV), Terrestrial LiDAR, and Brunton Compass Methods for Discontinuity Data Collection

Abstract

Traditionally, discontinuity measurements have been collected manually using a Brunton compass. Ground-based light detection and ranging (LiDAR) scanning has, in recent years, been included as a more efficient method of structural data collection. Emerging technology in the realm of unmanned aerial vehicles (UAVs) focuses on the use of aerial photogrammetry in order to collect data from regions that would be otherwise difficult or impossible to access, and has the added benefit of eliminating “shadow zones” (gaps in data) that are typically a limitation of terrestrial LiDAR methodology. This study compares discontinuity data acquisition via an unmanned aerial vehicle (UAV) to these established methods in order to determine if UAV technology can be used reliably to collect structural data. Two field sites in Virginia were scanned for this study—a cut slope in Deerfield along highway 629, and a shale pit in Cove Mountain. Approximately 300 Brunton compass mea- surements of orthogonal joint sets and bedding planes were taken at each site in order to provide a “control group” for orientation data. In addition, ground-based LiDAR scans and UAV photogrammetric data were collected at each location. Scans from the LiDAR unit and the UAV were converted into 3D point clouds for statistical comparison with manually collected data. Stereonets of each data set were also prepared for further comparison. Preliminary results indicate that discontinu- ity data collection from UAV closely matches the data collected using LiDAR or Brunton compass. R.