LiDAR stands for light detection and ranging. Using a laser pulse and a sensor it sends out a signal and measures the time it takes for that pulse to return. A distance is then derived from that information which determines where that point is in 3D space. Now repeat that between one hundred to seven hundred thousand times per second. With this scanning capability we are able to record things like vegetation, conductors, pylons and guy-wires with millimeters of accuracy.
Figure 1 is a section of powerline that was surveyed using an unmanned aerial vehicle (UAV) LiDAR system. The data captured was used to observe the power line right-of-way and determine line sag, structural integrity and vegetation clearances.
Surveying the ground when trees and brush are in the way can be challenging and time consuming for a ground survey team. Photogrammetry does not penetrate the canopy, leaving few options for companies to get a bare earth model. LiDAR penetrates and filters out the canopy, giving you a bare earth model of a large area that would have taken weeks for the ground team and would have been impossible using photogrammetry.