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Table 4 All the forage nutrient estimation models based on the spectral bands of the MSI and MWI

From: Mapping the forage nitrogen, phosphorus, and potassium contents of alpine grasslands by integrating Sentinel-2 and Tiangong-2 data

S2TG

N

P

K

RF

SVM

RF

SVM

RF

SVM

TG

S2

S2TG

S2TG-RFFS

S2TG-LASSO

TG

S2

S2TG

S2TG-RFFS

S2TG-LASSO

TG

S2

S2TG

S2TG-RFFS

S2TG-LASSO

TG

S2

S2TG

S2TG-RFFS

S2TG-LASSO

TG

S2

S2TG

S2TG-RFFS

S2TG-LASSO

TG

S2

S2TG

S2TG-RFFS

S2TG-LASSO

Number

14

10

26

13

9

14

10

26

13

9

14

10

26

11

5

14

10

26

11

5

14

10

26

16

4

14

10

26

16

4

R2

0.76

0.76

0.8

0.78

0.78

0.67

0.7

0.7

0.7

0.7

0.73

0.73

0.77

0.74

0.72

0.61

0.62

0.64

0.62

0.63

0.81

0.82

0.85

0.84

0.83

0.77

0.76

0.77

0.79

0.8

RMSE (%)

0.3

0.29

0.28

0.28

0.28

0.34

0.32

0.32

0.32

0.32

0.03

0.03

0.03

0.03

0.03

0.04

0.04

0.04

0.04

0.04

0.38

0.37

0.34

0.35

0.36

0.42

0.43

0.42

0.4

0.4

NRMSE

0.2

0.2

0.19

0.19

0.19

0.23

0.22

0.22

0.22

0.22

0.27

0.27

0.25

0.26

0.27

0.32

0.32

0.31

0.32

0.31

0.27

0.26

0.24

0.25

0.26

0.3

0.3

0.3

0.28

0.29

RPD

1.56

1.68

1.65

1.64

1.68

1.62

1.71

1.72

1.68

1.69

1.48

1.53

1.55

1.56

1.51

1.44

1.44

1.51

1.47

1.52

1.69

1.81

1.79

1.86

1.82

1.77

1.82

1.84

1.92

1.91

AIC

− 155

− 177

− 146

− 167

− 179

− 163

− 181

− 154

− 172

− 180

− 565

− 580

− 554

− 581

− 587

− 561

− 569

− 549

− 570

− 588

− 104

− 124

− 95

− 118

− 138

− 112

− 126

− 100

− 124

− 146

BIC

− 120

− 152

− 86

− 134

− 156

− 127

− 156

− 93

− 139

− 157

− 530

− 555

− 493

− 553

− 574

− 525

− 543

− 488

− 542

− 576

− 69

− 99

− 35

− 77

− 128

− 77

− 100

− 39

− 84

− 136

  1. The values of R2, RMSE, NRMSE, RPD, AIC, and BIC are the averages of 50 iterations of a tenfold CV. The R2 value is provided by the validation set data. The number refers to the number of spectral bands used for modeling. S2TG is the set of variables combining the MSI spectral bands and MWI spectral bands used for modeling, and S2TG-RFFS and S2TG-LASSO are the sets of suitable spectral bands from the MWI and MSI that were screened by the RFFS and LASSO algorithms, respectively. N nitrogen, P phosphorus, K potassium, S2 sentinel-2, TG Tiangong-2