Quantification of the spatial distribution of individual mangrove tree species derived from LiDAR point clouds

Progress in Earth and Planetary Science

Table 1 Accuracy evaluation of ALS point clouds and DEM by reference points

	Reference point			ALS			DEM	ALS error (m)		DEM error (m)	Remarks
	x	y	z	x	y	z	z	Horizontal	Vertical	DEM error (m)	Remarks
P1	21,417.7973	− 181,823.644	2.406	21,415.905	− 181,824.063	2.494	0.64416	–	–	–	Alongside the bridge structure
P2	21,397.5107	− 181,826.9974	5.275	21,397.599	− 181,826.956	5.369	–	0.097523587	0.094	–	Point outside the DEM
P3	21,427.9364	− 181,819.1984	0.831	21,429.953	− 181,819.101	0.889	0.81702	–	–	–	Alongside the tree canopy
P4	21,367.2226	− 181,925.6136	0.326	21,366.405	− 181,925.666	0.428	0.39588	0.819277438	0.102	0.06988
P5	21,468.486	− 181,796.9861	7.271	21,463.728	− 181,796.13	7.496	− 0.3383	–	–	–	On the bridge
P6	21,366.45	− 181,922.091	0.2929	21,366.472	− 181,922.054	0.368	0.346	0.043046486	0.0751	0.0531
P7	21,463.275	− 181,796.294	7.31	21,463.259	− 181,796.339	7.46	− 0.1786	0.047759816	0.15	–	On the bridge
P8	21,369.714	− 181,737.606	0.1061	21,369.675	− 181,737.646	0.101	− 0.2133	0.055865911	0.0051	0.31938
P9	21,406.48	− 181,805.46	1.9769	21,407.503	− 181,805.776	2.448	− 0.1335	–	–	–	Alongside the bridge structure
P10	21,431.488	− 181,818.516	0.8242	21,431.54	− 181,818.517	0.881	0.81866	0.052009614	0.0568	0.00554
P11	21,480.24	− 181,833.655	− 0.0487	21,480.334	− 181,833.577	− 0.04	− 0.0311	0.122147452	0.0087	0.01756
P12	21,404.474	− 181,782.139	0.2773	21,405.116	− 181,782.225	0.223	0.15956	–	–	–	Under the tree canopy
										DEM MAE (m)	0.093092
										DEM RMSE (m)	0.148354612