“… Linear methods, which analyze LiDAR cross-sections -strips and point lines (Hu and Ye, 2013), (Hosseini, 2014); Planar methods (grid-based methods), which construct projection of LiDAR point cloud using either height parameter (Kodors et al, 2014), indexes like echo-rate and variance (Chehata et al, 2009), combination of pixel features extracted from LiDAR and hyperspectral images (Jahan and Awrangjeb, 2017); Volume methods, which process filled and empty voxels (with and without points), (Wang et al, 2016), voxel features (Plaza-Leiva et al, 2017). The requirement "to satisfy regular point distribution" is mentioned in USGS "LiDAR Base Specification": "The spatial distribution of geometrically usable points will be uniform and regular.…”