saTransformation: Slope/Aspect Transformation (Temperature and Moisture)

In raff-k/GeoMorphTB: Computing various gradient and geomorphometric parameters

Description

Options are Stage’s (1976) COS, SIN; or Roberts & Cooper (1989) TRASP (topographic radiation aspect index). COS AND SIN - An a priori assumption of a maximum in the NW quadrant (45 azimuth) and a minimum in the SW quadrant can be replaced by an empirically determined location of the optimum (Stage, 1976). For slopes from 0 linearized and bounded from -1 to 1. Greater than 100 values greater than 100 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 (Roberts and Cooper 1989).

Usage

saTransformation(elevation = NULL, slope = NULL, aspect = NULL,
  zscale = "1.0", transType = "COS", output = NULL, load_output = TRUE,
  quiet = TRUE, ...)

Arguments

elevation	RasterLayer containing elevation values
slope	(optional) RasterLayer containing slope values. Value format must be percent. Default: NULL
aspect	(optional) RasterLayer containing aspect values. Note: North must be 0, and East must be 90. Default: NULL
zscale	Multiplicative factor to convert elevation units to horizontal units. Default: "1.0"
transType	Transformation type. Must be "COS", "SIN" or "TRASP". Default: "COS"
output	(optional) file name to save output. Default: NULL
load_output	If TRUE, function output file will be loaded into R. Default: TRUE
quiet	IF FALSE, console messages are shown. Default: TRUE
...	optional parameter for [RQGIS::run_qgis()]

Value

RasterLayer saTransformation

raff-k/GeoMorphTB documentation built on Jan. 5, 2022, 2:08 p.m.