Surface Area Ratio

Source: R/sar.R

Calculates the Berry (2002) Surface Area Ratio based on slope

sar(x, s = NULL, ...)

Arguments

x

raster object
s

cell resolution (default is NULL, not needed if projection is in planar units)
...

Additional arguments passed to raster::calc

Value

raster class object of Berry (2002) Surface Area Ratio

Note

SAR is calculated as: resolution^2 * cos( (degrees(slope) * (pi / 180)) )

References

Berry, J.K. (2002). Use surface area for realistic calculations. Geoworld 15(9):20-1.

Author

Jeffrey S. Evans <jeffrey_evans@tnc.org>

Examples

  library(raster)
  data(elev)
  surface.ratio <- sar(elev, s=90)
  plot(surface.ratio)