Class | Variable |
Formula (“Terrain” package, Hijmans et al. 2015) | Reference |
---|---|---|---|
DSM | |||
Slope | SLOPE_{sd} | Slope | (Horn 1981) |
Topographic position index | TPI_{mean} and TPI_{sd} | where \( TPI=y-\sum \limits_{i=1}^8\frac{y_i}{8} \), with y is the altitude of a cell and y_{i} is the altitude of the i-th adjacent cell | (Wilson et al. 2007) |
Terrain ruggedness index | TRI_{mean} and TRI_{sd} | where \( TRI=\sum \limits_{i=1}^8\frac{\left|{y}_i-y\right|}{8} \), with y is the altitude of a cell and y_{i} is the altitude of the i-th adjacent cell | |
Roughness | ROUGHNESS_{mean} and ROUGHNESS_{sd} | Roughness is the difference between the maximum and the minimum value of a cell and its 8 surrounding cells | |
Texture |
dsm_GLCM_mean (window size of 3 × 3 pixels and a 45 degree shift) |
“mean”, “variance”, “homogeneity”, “contrast”, “dissimilarity”, “entropy”, “second_moment”, “correlation” |