Function reference • statisticalRoughness

Hurst exponents calculation
Raster operations
`all_rasters_to_polygons()`	This function transforms all rasters found into a directory into SpatVector and save them to shapefiles.
`compute_Hurst_rasters()`	Wrapper function around the computation of Hurst coefficients from box-counting and log-log regression
`compute_Hurst_rasters_internal()`	Compute Hurst rasters from a log-log regression between scales and mean standard deviation
`get_mean_res()`	Compute the mean resolution of lat long raster in meters
`get_mean_sd_rasters()`	Compute box-counting mean standard deviation rasters
`merge_Hurst_rasters()`	merge all Hurst raster
Factoring
`get_all_R_L()`	Get a list of upper spatial scale at which the roughness coefficient is calculated
`get_factors()`	Get factor of an integer
2D Fourier analysis of topography
Basic functions
`Hann2D()`	A two-dimensional Hann window
`detrend_dem()`	Detrends a DEM with `pracma::odregress()`
`fft2D()`	Perfoms a two-dimensional Fourier transform
`get_beta()`	Derive the slope of the binned power spectrum
`pad_mat()`	Pads a matrix with zeros so it has a given dimension
Rotating DEMs
`bin()`	Bins a power spectrum
`filter_spectral_power_matrix()`	Returns a quantile-filtered raster of the logarithm of the real-part of the normalized spectral power matrix
`get_fourier_angle()`	Get the angle of the 2D Fourier spectrum
`get_normalized_spectral_power_matrix()`	Normalizes the spectral power matrix with the background spectrum
`rotate_raster()`	Rotates the detrended DEM according to the main direction of the Fourier spectrum
Visualizations
`matrix_for_rayshader()`	Transforms matrix for be used by `rayshader`.
`spectrum_plot()`	Plot a radial Fourier spectrum
`view_matrix()`	Visualizes values of a matrix
Anisotropic analysis of topography
Roughness and anisotropy exponents
`HHCF()`	Internal; derives a one-dimensional height-height correlation function
`alpha_plot()`	Internal companion function to `get_alpha`.
`filter_alpha()`	Filters the alpha values of alpha returned by `get_all_alpha()` between zero and the 99.9% quantile of the initial alphas
`get_all_alpha()`	Wrapper to extract all roughness exponents from the HHCFs
`get_all_alpha_()`	Wrapper to extract all roughness exponents from the HHCFs
`get_alpha()`	Estimates the roughness exponent from the HHCF from spline fit.
`get_alpha_()`	Estimates the roughness exponent from the HHCF from spline fit.
`get_hhcf()`	This wrapper function derives the one-dimensional `HHCF()` for all columns or rows of a matrix
`get_hhcf_()`	This wrapper function derives the one-dimensional `HHCF()` for all columns or rows of a matrix
`get_kruskal_flag()`	Computes a Kruskal-Wallis ranksum test for significant differences between the distributions of alpha
`get_zeta()`	Wrapper function to derive the anisotropy exponent from a non-rotated raster
`get_zeta_()`	Internal function to derive the anisotropy exponent from two roughness exponents
`get_zeta_df()`	Get the value of the anisotropy exponent and associated metrics for a tile of elevation
`get_zeta_raster()`	Get the value of the anisotropy exponent for a tile of elevation
`summarise_alpha()`	Wrapper to summarize `alpha` values
Postprocessing and visualizations
`clamp_raster_sigmas()`	Filter outliers from a list of raster data using data from all rasters
`crossscale_correlations()`	Creates a facet plot of correlation between `selected` attributes from a `raster_list` representing different `spatial_scales`
`four_values_check()`	Check that at least four values of the raster stack are not `NA` for each element of `raster_list`
`make_all_plots()`	Wrapper function around `make_stacked_density_plot()` and `modes_from_stacked_density()`
`make_angular()`	Transform a 360 degrees variable to a 180 degrees
`make_leaflet_map()`	Produces a leaflet map
`make_stacked_density_plot()`	Makes stacked density plot
`modes_from_stacked_density()`	Extract the modal values of the stacked density plot
`raster_select()`	Selecting raster bands
`read_zeta_raster()`	Read zeta raster from destination
`reduce_spatial_noise()`	Convolves with a 3x3 mean kernel with weights of 1
`slice_clamp()`	Slicing and clamping of rasters

Reference

Hurst exponents calculation

Raster operations

Factoring

2D Fourier analysis of topography

Basic functions

Rotating DEMs

Visualizations

Anisotropic analysis of topography

Roughness and anisotropy exponents

Postprocessing and visualizations