In the second of seven videos, Dr. Chris Hopkinson describes the data that comes back from a LiDAR survey. He points out that the point cloud attributes are different as the radar pulses come back from different forms for LiDAR scanners. He explains multiple returns, primary returns and secondary returns and how that supplies more information in the point cloud data. Canopy penetration is important when ground elevation modelling is objective. Landscape surfaces are one model product (canopy height modelling in forestry, building modelling in urban design). Digital elevation modelling requires last returns but last returns are not necessarily ground returns. He finishes by discussing return intensity and how it can be used to interpret surfaces and moisture contents. Colour imaging and LiDAR can be combined for additional surface interpretation.
Dr. Chris Hopkinson's presentation is a workshop on LiDAR and water resources applications. The seven videos are part of University of Lethbridge's LiDAR and SAR workshop, June 26, 27, 2014.