spatialEco (version 0.1-7)

sa.trans: Trigonomic transformation of a slope and aspect interaction

Description

The trigonomic Stage (1978) [slope * cos(aspect)] or [slope * sin(aspect)]

Usage

sa.trans(slope, aspect, type = "cos", slp.units = "degrees",
  asp.units = "degrees")

Arguments

slope

slope values in degrees, radians or percent

aspect

aspect values in degrees or radians

type

Type of transformation, options are: "cos", "sin",

slp.units

Units of slope values, options are: "degrees", "radians" or "percent"

asp.units

Units of aspect values, options are: "degrees" or "radians"

Value

A vector of the modeled value

References

Stage, A. R. 1976. An Expression of the Effects of Aspect, Slope, and Habitat Type on Tree Growth. Forest Science Vol 22, No 3, 457-460.

Examples

 sa.trans(slope = 48.146, aspect = 360.000)

 library(raster)
 data(elev)
 sa <- raster::terrain(elev, opt=c("slope", "aspect"), unit="degrees")
 scosa <- raster::overlay(sa[[1]], sa[[2]], fun = sa.trans)