. 2022 Jul 8;22(14):5129. doi: 10.3390/s22145129

Table 3.

The optimal SOM prediction model (PLSR or SVR) in the four major rivers.

Soil Sample		Model	Wavelength Range (nm)	Pre-Processing	Rc²	RMSEc (g kg⁻¹)	Rv²	RMSEv (g kg⁻¹)	Factor
Total		PLSR	400–1100	Normalization	0.657	11.23	0.630	11.66	8
Total		SVR	350–2500	1st derivative (20 nm)	0.716	10.55	0.678	11.12	-
GR	Total	PLSR	400–1100	Normalization	0.668	7.47	0.526	8.93	8
	Total	SVR	350–2500	SNV	0.627	8.54	0.544	9.17	-
	WA	PLSR	350–2500	Normalization	0.680	8.10	0.556	9.60	5
	WA	SVR	350–2500	1st derivative (20 nm)	0.649	9.56	0.531	10.38	-
	DWPZ	PLSR	350–2500	SNV	0.713	5.95	0.629	6.83	4
	DWPZ	SVR	350–2500	Normalization	0.794	5.33	0.735	5.97	-
NR	Total	PLSR	350–2500	-	0.766	9.81	0.659	11.96	7
	Total	SVR	350–2500	1st derivative (20 nm)	0.735	10.54	0.662	11.84	-
	WA	PLSR	400–1100	1st derivative (20 nm)	0.912	5.57	0.746	9.55	9
	WA	SVR	1100–2500	1st derivative (20 nm)	0.706	10.89	0.470	13.80	-
	DWPZ	PLSR	400–1100	-	0.806	8.28	0.703	10.29	7
	DWPZ	SVR	350–2500	2nd derivative (20 nm)	0.858	7.35	0.644	10.29	-
YSR	Total	PLSR	350–2500	MSC	0.829	7.31	0.678	10.21	8
	Total	SVR	400–1100	1st derivative (15 nm)	0.708	9.96	0.675	10.42	-
	WA	PLSR	350–2500	SNV	0.912	5.79	0.826	8.17	7
	WA	SVR	350–2500	1st derivative (15 nm)	0.838	9.03	0.682	11.76	-
	DWPZ	PLSR	350–2500	SNV	0.911	4.80	0.729	8.42	11
	DWPZ	SVR	350–2500	SNV	0.710	9.78	0.596	11.22	-
HR	Total	PLSR	350–2500	SNV	0.704	4.69	0.615	5.38	5
	Total	SVR	350–2500	SNV	0.755	4.55	0.691	4.96	-
	WA	PLSR	350–2500	SNV	0.810	3.62	0.657	4.92	5
	WA	SVR	350–2500	SNV	0.731	4.90	0.675	5.20	-
	DWPZ	PLSR	350–2500	SNV	0.877	2.31	0.694	3.72	6
	DWPZ	SVR	400–1100	SNV	0.689	3.82	0.559	5.76	-