Table 2. Results of leave-one-out cross validation for PLSR of both reflectance and absorbance treated by fractional derivatives.
| Order | Reflectance | Absorbance | ||||||
|---|---|---|---|---|---|---|---|---|
| Latent variables | R2 | RMSE (dS m−1) |
RPD | Latent variables | R2 | RMSE (dS m−1) |
RPD | |
| 0.0 | 4 | 0.64 | 9.27 | 1.30 | 3 | 0.58 | 9.80 | 1.23 |
| 0.1 | 4 | 0.66 | 9.07 | 1.33 | 4 | 0.63 | 9.37 | 1.29 |
| 0.2 | 4 | 0.69 | 8.75 | 1.38 | 4 | 0.68 | 8.90 | 1.36 |
| 0.3 | 4 | 0.71 | 8.56 | 1.42 | 4 | 0.67 | 8.98 | 1.35 |
| 0.4 | 5 | 0.77 | 7.77 | 1.57 | 4 | 0.68 | 8.90 | 1.36 |
| 0.5 | 2 | 0.54 | 10.08 | 1.19 | 2 | 0.52 | 10.27 | 1.17 |
| 0.6 | 2 | 0.56 | 9.93 | 1.21 | 2 | 0.55 | 10.03 | 1.20 |
| 0.7 | 5 | 0.81 | 7.20 | 1.70 | 3 | 0.67 | 8.97 | 1.35 |
| 0.8 | 3 | 0.71 | 8.49 | 1.43 | 3 | 0.66 | 9.04 | 1.34 |
| 0.9 | 3 | 0.72 | 8.43 | 1.44 | 3 | 0.68 | 8.87 | 1.36 |
| 1.0 | 3 | 0.70 | 8.70 | 1.39 | 3 | 0.66 | 9.05 | 1.34 |
| 1.1 | 5 | 0.84 | 6.63 | 1.86 | 5 | 0.79 | 7.43 | 1.65 |
| 1.2 | 5 | 0.84 | 6.76 | 1.82 | 5 | 0.82 | 7.03 | 1.75 |
| 1.3 | 5 | 0.84 | 6.73 | 1.83 | 5 | 0.84 | 6.68 | 1.84 |
| 1.4 | 5 | 0.84 | 6.36 | 1.94 | 5 | 0.84 | 6.18 | 1.99 |
| 1.5 | 5 | 0.84 | 6.18 | 2.01 | 5 | 0.87 | 5.23 | 2.40 |
| 1.6 | 5 | 0.86 | 6.00 | 2.07 | 5 | 0.84 | 6.06 | 2.05 |
| 1.7 | 5 | 0.85 | 6.16 | 2.02 | 5 | 0.84 | 6.07 | 2.04 |
| 1.8 | 5 | 0.84 | 6.19 | 2.00 | 5 | 0.83 | 6.09 | 2.03 |
| 1.9 | 5 | 0.84 | 6.73 | 1.83 | 5 | 0.83 | 6.85 | 1.79 |
| 2.0 | 5 | 0.83 | 6.85 | 1.79 | 5 | 0.83 | 6.98 | 1.76 |