Abbreviations
B2D	Bounded Bivariate Density
NaN	Non-measured points
SWLI	Scanning White Light Interferometry
UTMD	Uncertainties are Topographically and Material Dependent
WLI	White Light Interferometry
Surface characterization parameters
$R_a/S_a$	Arithmetic average roughness (2D/3D)
$R_q/R_q$	Root mean square roughness (2D/3D)
$S_{dq}$	Root mean square gradient (3D)
Measurement information
A	Measuring instruments
C	Conditions of measurement
M	Set of measured maps (multi-maps)
N	Number of topographic measurements
S	Surfaces
X	Locations of measurement
Measurement parameters
Π	Form removal polynomial
i	Coordinates of a surface point along the x-axis
I	X size of the measured surface topography
j	Coordinates of a surface point along the y-axis
J	Y size of the measured surface topography
n	Number of the measured surface topography
x	X position in a surface
y	Y position in a surface
z	Height of a surface point
$l_c$	Coherence length
${\lambda }_0$	Central wavelength
Fluctuation/gradient parameters
δi,j,n	Localized uncertainty in the map n at the location (i, j)
δz	Measurement uncertainties
δr	Random uncertainty introduced by the environmental issue
μ	Mean height
σ	Fluctuation, i.e., standard deviation of the height
σh	Standard deviation of the rough surface height distribution
$\widehat{\sigma }$	Normalized fluctuation
$\mathsf{\nabla }$	Gradient of the normal to the surface
$\widehat{\mathsf{\nabla }}$	Mean gradient
Qq	Moments of all gradients
$\widehat{Q_q}$	Moments of the mean gradient
Se	Standardized fluctuations
c	Gradient effect factor
Spatial representation of gradient
$\overrightarrow{x},\overrightarrow{y},\overrightarrow{z}$	Cartesian coordinate system
${\nu }_{i,j,n}$	Vector normal to the facet
${\alpha }_{i,j,n}$	Angle between z axis and the vector normal to the facet
Statistical parameters
p	Probability density
Q5	5th percentile
Q50	Median
Q95	95th percentile