Solar-radiation Aspect Index
Calculates the Roberts and Cooper (1989) Solar-radiation Aspect Index
Roberts and Cooper (1989) rotates (transforms) the circular aspect to assign a value of zero to land oriented in a north-northeast direction, (typically the coolest and wettest orientation), and a value of one on the hotter, dryer south-southwesterly slopes. The result is a continuous variable between 0 - 1. The metric is defined as: trasp = ( 1 - cos((pi/180)(a-30) ) / 2 where; a = aspect in degrees
trasp(x, ...)
x |
raster object |
... |
Additional arguments passed to raster::calc |
raster class object of oberts and Cooper (1989) Solar-radiation Aspect Index
Jeffrey S. Evans <jeffrey_evans@tnc.org>
Roberts. D.W., and Cooper, S.V. (1989). Concepts and techniques of vegetation mapping. In Land Classifications Based on Vegetation: Applications for Resource Management. USDA Forest Service GTR INT-257, Ogden, UT, pp 90-96
library(raster)
data(elev)
s <- trasp(elev)
plot(s)Please choose more modern alternatives, such as Google Chrome or Mozilla Firefox.