A GIS-Based Algorithm to Generate a Lidar Pit-Free Canopy Height Model

Lidar has provided significant benefits for forest development and engineering operations and provides a good means to collect information on forest stands. A common analysis using LiDAR data computes the CHM as a difference between DSM and DTM, create a DTM from the ground returns and a DSM from the first returns and subtract the two rasters, but how exactly are generated the DTM and the DSM. Irregular height variations, called data pits are present in the CHM and appear when the first Lidar return is far below the canopy. The purpose of this study is an approach that computes the CHM directly from height-normalized LiDAR points.