Roughness

Draft: written, not yet checked by a person Operation · roughness

The difference between the highest and lowest elevation in each cell's 3 by 3 neighbourhood.

Pitfall. Several unrelated measures are called roughness (a range, a standard deviation, a multiscale signature); this one is the range of a 3 by 3 window.

About this operation
Also called	surface roughness, local relief, gdaldem roughness
Group	`raster/terrain`
Checks	`raster.nodata`
Pitfalls	1 listed above
Columbus tool	Not stated
Notes	Not stated
Status	active
Broader	Not stated
Narrower	Not stated
Related	`terrain-ruggedness-index` `topographic-position-index` `focal-statistics`

Parameters

Not stated

Inputs and outputs

Direction	Name	Type	Geometry	Note
Input	`raster`	raster	Not stated	An elevation model.
Output	`output`	raster	Not stated	Not stated

In each engine

Engine	Tool	Parameters	Differences
`gdal`	`gdal raster roughness`	`raster` → `input` `output` → `output`	None noted
`postgis-raster`	`st_roughness`	`raster` → `rast`	None noted
`qgis`	`gdal:roughness`	`raster` → `INPUT` `output` → `OUTPUT`	Cells on the raster's edge are left as nodata unless edges are computed (COMPUTE_EDGES).
`terra`	`terra::terrain`	`raster` → `x`	None noted Preset: `{"v":"roughness"}`
`xarray-spatial`	`xrspatial.roughness`	`raster` → `agg`	Takes an xarray DataArray; edge cells are NaN by default (boundary = 'nan').