Table 1.
The optimal band or band combinations for the four studied narrow-band models
| Models | Calculation equations | Band or band combinations | Calibration (n = 454) | Validation (n = 120) | ||
|---|---|---|---|---|---|---|
| R2 | RMSE | R2 | RMSE | |||
| SB | Band1 | 627 | 0.7055 | 0.0959 | 0.6875 | 0.0926 |
| BR | Band1/Band2 | 755, 759 | 0.0526 | 0.172 | 0.0981 | 0.1574 |
| BS | Band1 − Band2 | 437, 444 | 0.8121 | 0.0766 | 0.7911 | 0.0757 |
| NBD | (Band1 − Band2)/(Band1 + Band2) | 755, 759 | 0.0507 | 0.1721 | 0.0962 | 0.1575 |
For SB, only one optimal band was selected; for the other three, “Band1” and “Band2” represent the best band combinations. The model with the highest R2 value for the calibration dataset was shown in bold
SB single band, BR band ratio, BS band subtraction, NBD normalized band difference