Calculates Roughness Index-Elevation — RIE • MultiscaleDTM

Calculates Roughness Index-Elevation. This is the standard deviation of residual topography in a focal window where residual topography is calculated as the focal pixel minus the focal mean.

Usage

RIE(
  r,
  w = c(3, 3),
  na.rm = FALSE,
  include_scale = FALSE,
  filename = NULL,
  overwrite = FALSE,
  wopt = list()
)

Arguments

r: DTM as a SpatRaster or RasterLayer
w: A vector of length 2 specifying the dimensions of the rectangular window to use where the first number is the number of rows and the second number is the number of columns. Window size must be an odd number. Default is 3x3.
na.rm: A logical indicating whether or not to remove NA values before calculation of SD
include_scale: logical indicating whether to append window size to the layer names (default = FALSE)
filename: character Output filename.
overwrite: logical. If TRUE, filename is overwritten (default is FALSE).
wopt: list with named options for writing files as in writeRaster

Value

a SpatRaster or RasterLayer

Details

Note the original paper by Cavalli et al (2008) uses a fixed 5x5 window and uses 25 as the denominator indicating use of the population standard deviation. This implementation provides a flexible window size and istead calculates the sample standard deviation which uses a denominator of n-1.

References

Cavalli, M., Tarolli, P., Marchi, L., Dalla Fontana, G., 2008. The effectiveness of airborne LiDAR data in the recognition of channel-bed morphology. CATENA 73, 249–260. https://doi.org/10.1016/j.catena.2007.11.001

Examples

r<- rast(volcano, extent= ext(2667400, 2667400 + 
ncol(volcano)*10, 6478700, 6478700 + nrow(volcano)*10), 
crs = "EPSG:27200")
rie<- RIE(r, w=c(5,5), na.rm = TRUE)
plot(rie)