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Table 2 Descriptive statistics of transformed variables and the corresponding transformation

From: Estimating topsoil texture fractions by digital soil mapping - a response to the long outdated soil map in the Philippines

Parameters

Tukey’s power transformation

Minimum

Median

Mean

Maximum

CV (%)

Skewness

Kurtosis

Dependent Variables

 Clay

(x - 5)^(0.375)

6.54

8.46

8.44

10.01

9.23

0.000

2.20

 Sand

(x)^(0.3)

1.56

2.47

2.47

3.51

16.52

−0.009

2.39

 Silt

(63 - x)^(0.5)

4.05

5.75

5.76

7.28

11.25

−0.054

2.67

Independent Variables or Predictors

 Analytical hillshading

(x + 2)^(0.075)

1.06

1.08

1.08

1.11

0.82

0.002

3.30

 Aspect

x

0.12

3.28

3.23

6.28

56.45

−0.041

1.79

 Catchment area

-(x - 12)^(−0.075)

−0.71

−0.60

−0.60

−0.45

−9.13

0.005

2.47

 Channel network base level

(x + 1)^(0.125)

1.24

1.70

1.68

2.20

15.01

0.175

1.71

 Curvature classification

(23 - x)^(1.6)

76.16

113.98

114.87

150.93

19.82

−0.058

1.75

 Elevation

log10(x)

0.64

1.83

1.76

2.73

30.02

0.024

1.60

 Flow accumulation

(x - 15)^(0.075)

1.40

1.66

1.65

2.238

11.38

0.207

2.34

 Landsat 8 Band 1

-(−x)^(−1)

12.54

23.61

24.00

31.39

11.17

0.108

5.01

 Landsat 8 Band 10

(x - 13)^(0.375)

1.25

1.54

1.52

1.86

6.06

−0.093

4.30

 Landsat 8 Band 11

(x - 10)^(0.125)

0.97

1.09

1.09

1.19

2.89

−0.018

4.53

 Landsat 8 Band 2

-(x)^(−0.8)

−15.75

−11.98

−12.13

−7.82

−11.63

−0.016

3.40

 Landsat 8 Band 3

-(x)^(−0.55)

−5.28

−4.42

−4.45

−3.46

−7.48

0.006

3.14

 Landsat 8 Band 4

-(x)^(−0.375)

−3.37

−2.86

−2.89

−2.36

−6.83

−0.029

2.69

 Landsat 8 Band 5

-(x + 1)^(−2.475)

−0.59

−0.49

−0.49

−0.36

−8.27

0.008

3.11

 Landsat 8 Band 6

-(x + 1)^(−10)

−0.32

−0.21

−0.21

−0.07

−20.91

0.022

2.95

 Landsat 8 Band 7

-(x)^(−0.725)

−8.06

−6.01

−6.05

−3.76

−11.85

−0.037

3.34

 Latitude

log10(x)

6.05

6.05

6.05

6.05

0.02

0.319

3.27

 Longitude

log10(x)

5.74

5.75

5.75

5.75

0.03

0.190

3.26

 LS factor

log10(x)

−1.52

−0.74

−0.81

1.03

−86.99

0.398

1.95

 Mass balance index

(3.4 - x)^(1.525)

4.74

6.48

6.51

8.16

12.97

−0.066

2.12

 Mountain ridge proximity

(x)^(0.95)

159.10

3124.60

2895.20

6592.80

46.60

0.016

3.08

 MRVBF

(x - 3)^(3)

−27.00

−27.00

−14.58

8.00

−89.63

0.253

1.36

 Mid-slope position

-(x - 3)^(−4)

−0.06

−0.03

−0.03

−0.01

−36.45

0.005

1.81

 NDVI

-(x - 1)^(−1)

1.79

3.36

3.36

5.18

19.03

0.062

2.48

 Normalized height

-(x + 2)^(−7.575)

0.00

0.00

0.00

0.00

−62.97

−0.004

1.54

 Overland flow distance

(x + 10)^(0.075)

1.23

1.32

1.32

1.42

3.59

0.000

2.14

 Profile curvature

-(x + 1)^(−10)

−1.11

−1.00

−1.00

−0.89

−3.68

0.176

3.64

 S factor

log10(x)

−1.52

−0.78

−0.89

0.52

−68.47

0.208

1.57

 SAGA wetness index

(x - 2)^(0.475)

1.80

2.49

2.47

3.13

12.80

−0.026

2.06

 Sky view factor

-(1 - x)^(−0.125)

−2.72

−1.91

−1.88

−1.31

−11.82

0.011

3.82

 Slope

(x)^(0.475)

0.00

2.14

2.12

4.91

45.98

0.098

3.11

 Slope height

(x - 1)^(0.075)

0.75

1.10

1.09

1.40

12.23

−0.048

2.06

 Stream proximity

(x + 6)^(0.125)

1.33

2.03

2.03

2.75

18.65

−0.036

1.83

 Terrain ruggedness index

-(x + 1)^(−0.85)

−1.00

−0.66

−0.66

−0.26

−25.45

0.038

2.47

 Valley depth

-(x + 3)^(−0.325)

−0.65

−0.42

−0.42

−0.18

−22.37

0.017

2.89

 Vertical distance to channel network

(x)^(0.3)

0.00

0.55

0.54

1.10

52.97

−0.075

2.10

 Vertical overland flow distance

(x)^(0.175)

0.65

1.15

1.14

1.60

16.23

−0.043

2.81