Sdq (Root mean square gradient)

This parameter is calculated as a root mean square of slopes at all points in the definition area.

Sdq of a completely level surface is 0.
Sdq (Root mean square gradient)

When a surface has any slope, Sdq becomes larger. The following surface is a plane with gradient components of 45 degrees and its Sdq is 1.
Sdq (Root mean square gradient)

Sdq (Root mean square gradient)

Search from the parameters list

Height	Sa (arithmetical mean height)
Sz (Maximum height)
Sq (Root mean square height)
Ssk (Skewness)
Sku (Kurtosis)
Sp (Maximum peak height)
Sv (Maximum pit height)
Spatial	Sal (Auto-correlation length) / Str (Texture aspect ratio)
Std* (Texture direction)
Hybrid	Sdq (Root mean square gradient)
Sdr (Developed interfacial area ratio)
Functional	Smr(c) (Areal material ratio)
Smc(mr) (Inverse areal material ratio)
Sk (Core roughness depth)
Spk (Reduced peak height)
Svk (reduced dale height)
Smr (Peak material portion)
Smr2 (Valley material portion (percentage of the measurement area that comprises the deeper valley structures associated with Svk))
Sxp (Peak extreme height)
Functional volume	Vvv (Dale void volume)
Vvc (Core void volume)
Vmp (Peak material volume)
Vmc (Core material volume)
Feature	Spd (Density of peaks)
Spc (Arithmetic mean peak curvature)
S10z / S5p / S5v / Sda(c) / Sha(c) / Sdv(c) / Shv(c)

Height

Sa (arithmetical mean height)

Sz (Maximum height)

Sq (Root mean square height)

Ssk (Skewness)

Sku (Kurtosis)

Sp (Maximum peak height)

Sv (Maximum pit height)

Spatial

Sal (Auto-correlation length) / Str (Texture aspect ratio)

Std* (Texture direction)

Hybrid