Comparing the Use of Terrestrial LiDAR Scanners and Pin Profilers for Deriving Agricultural Roughness Statistics

Adequate descriptions of soil surface roughness are vital for the accurate retrieval of soil moisture maps from remote sensing products. Terrestrial laser scanners (TLSs) have the potential to offer a more comprehensive method of measuring surface roughness than traditional techniques, but are underused in this application. This research examines the use of TLSs for measuring the surface roughness of bare agricultural fields in Elora, Ontario. Through the development and application of an innovative plug-in called Roughness from Point Cloud Profiles (RPCP), this research compares TLS surface roughness characterizations to those derived from a pin profiler. In most cases, the root mean square height (RMSH) measurements obtained from the pin profiler are within 1.5 cm of those obtained from Light Detection and Ranging (LiDAR). Nearly 90% of the l measurements obtained from the TLS were >5 cm larger than those from the pin profiler. Discrepancies between pin profiler and TLS roughness characterizations can be partially explained by LiDAR shadowing in some cases, but are likely caused by other factors such as de-trending techniques, profile length, and profile orientation. The results of this research illustrate roughness variations across fields and between roughness profile orientations according to tillage structures.