Table 1 MERIT-DEM derived geomorphometric variables.

First order derivative

Slope

slope

GDAL: gdaldem⁶⁶

Aspect

aspect

GDAL: gdaldem⁶⁶

Aspect cosine

aspect-cosine

GDAL: gdaldem gdal_calc.py⁶⁶

Aspect sine

aspect-sine

GDAL: gdaldem gdal_calc.py⁶⁶

Eastness

eastness

GDAL: gdaldem gdal_calc.py⁶⁶

Northness

northness

GDAL: gdaldem gdal_calc.py⁶⁶

Convergence

convergence

GRASS GIS: r.convergence⁶⁷

Compound topographic index

cti

GRASS GIS: r.watershed⁶⁷

Stream power index

spi

GRASS GIS: r.watershed⁶⁷

East-West first order partial derivative

dx

GRASS GIS: r.slope.aspect⁶⁷

North-South first order partial derivative

dy

GRASS GIS: r.slope.aspect⁶⁷

Second order derivative

Profile curvature

pcurv

GRASS GIS: r.slope.aspect⁶⁷

Tangential curvature

tcurv

GRASS GIS: r.slope.aspect

East-West second order partial derivative

dxx

GRASS GIS: r.slope.aspect⁶⁷

North-South second order partial derivative

dyy

GRASS GIS: r.slope.aspect⁶⁷

Second order partial derivative

dxy

GRASS GIS: r.slope.aspect⁶⁷

Ruggedeness

Elevation standard deviation

elev-stdev

PKTOOLS: pkfilter⁶⁹

Terrain ruggedness index

tri

GDAL: gdaldem⁶⁶

Roughness

roughness

GDAL: gdaldem⁶⁶

Vector ruggedness measure

vrm

GRASS GIS: r.vector.ruggedness.py⁶⁷

Topographic position index

tpi

GDAL: gdaldem⁶⁶

Maximum multiscale deviation

dev-magnitude

Whitebox: MaxElevationDeviation⁶⁸

Scale of the maximum multiscale deviation

dev-scale

Whitebox: MaxElevationDeviation⁶⁸

Maximum multiscale roughness

rough-magnitude

Whitebox: MultiscaleRoughness⁶⁸

Scale of the maximum multiscale roughness

rough-scale

Whitebox: MultiscaleRoughness⁶⁸

geomorphological forms

Geomorphon

geom

GRASS: r.geomorphon⁶⁷