| trasp {spatialEco} | R Documentation |
Solar-radiation Aspect Index
Description
Calculates the Roberts and Cooper (1989) Solar-radiation Aspect Index
Usage
trasp(x, ...)
Arguments
x |
A terra SpatRaster object |
... |
Additional arguments passed to terra::app |
Details
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
Value
A terra SpatRaster object of Roberts and Cooper (1989) Solar-radiation Aspect Index
Author(s)
Jeffrey S. Evans <jeffrey_evans@tnc.org>
References
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
Examples
library(terra)
elev <- rast(system.file("extdata/elev.tif", package="spatialEco"))
s <- trasp(elev)
plot(s)