Lorey's height regression for ICESAT-GLAS waveforms in hyrcanian deciduous forests of Iran

摘要

Since Lidar technology provides the most direct measurements of 3D of phenomena, it plays a critical role in a variety of applications. Forest canopy height as a main factor in forest biomass estimation is costly and time consuming to be measured on the ground. This study aims to estimate Lorey's height “H” using GLAS data based on regression models. Different metrics like waveform extent “W”, trail-edge extent “Htrail” and lead-edge extent “H” were extracted from waveforms and a terrain index “TI” was also calculated using a digital elevation model. H estimated using multiple regression models were compared to field measurements data. A 5-fold cross validation method was used to validate the results. Best model with lowest AIC (297.440) was resulted using combination of W and TI (R=0.72; RMSE= 5.04m). The results show capability of ICESat-GLAS to estimate Lorey's height in sloped area with a simple regression model. It is prospected to reach better result using other statistical methods and also improvement of processing techniques for LiDAR waveforms in the case of sloped terrain.