trasp: Solar-radiation Aspect Index

Description Usage Arguments Value Note Author(s) References Examples

View source: R/trasp.R

Description

Calculates the Roberts and Cooper (1989) Solar-radiation Aspect Index

Usage

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trasp(x, ...)

Arguments

x

raster object

...

Additional arguments passed to raster::calc

Value

raster class object of oberts and Cooper (1989) Solar-radiation Aspect Index

Note

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

Author(s)

Jeffrey S. Evans <[email protected]>

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

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  library(raster)
  data(elev)
  s <- trasp(elev)
    plot(s)
    

jeffreyevans/spatialEco documentation built on Nov. 10, 2018, 4:13 a.m.