From: Global polygons for terrain classification divided into uniform slopes and basins
Attribute | Calculation method | Description |
---|---|---|
lnSLOPE | ln (SLOPE + 1) SLOPE: slope gradient (degrees) calculated from the 90 m DEM interpolated by the bilinear option | SLOPE was calculated within 3 by 3 cells windows, using QGIS 3.14, by the Horns method |
lnHAND | ln (HAND + 1) HAND: Height Above the Nearest Drainage (m) | HAND was calculated by the method of Yamazaki et al. (2012) and Yamazaki et al. (2019) |
TEXTURE | Density within a 10-cell radius of pits and peaks obtained by the difference between the Original DEM and the 3 × 3 median filtered DEM. Original DEM: the 90-m DEM interpolated by the nearest neighbor option | The surface texture of Iwahashi and Pike (2007). TEXTURE was calculated by the “terrain surface texture” tool of SAGA (Conrad 2012a) in QGIS 3.4 (Threshold: 5-m, radius: 10 cells, no distance weighting) |
CONVEXITY | Density within a 10-cell radius of convex points obtained by processing the DEM with a 3 × 3 Laplacian filter. Original DEM: the 90 m DEM interpolated by the nearest neighbor option | The local convexity of Iwahashi and Pike (2007). CONVEXITY was calculated by the “terrain surface convexity” tool of SAGA (Conrad 2012b) in QGIS 3.4 (Threshold: 1-m, radius: 10 cells, no distance weighting) |
Sinks | Sinks is the following region: ((Filled DEM)—(Original DEM)) > 0. Original DEM: the 90-m DEM interpolated by the bilinear option. Filled DEM: DEM with the surface depressions (sinks) filled in | Filled DEM was calculated by the “Fill Sinks (Wang & Liu)” (Wang and Liu 2006) tool of SAGA in QGIS 3.4 |