raster (version 1.8-12)

hillShade: Hill shading

Description

Compute hill shade from slope and aspect layers. Slope should be expressed as a tangent (fraction), and aspect layers should be in radians. Slope and aspect can be computed with slopeAspect. A hill shade layer is often used as a backdrop on top of which another, semi-transparant, layer is drawn.

Usage

hillShade(slope, aspect, declination, direction, filename='', ...)

Arguments

slope

RasterLayer object with slope values expressed as a fraction (tangent)

aspect

RasterLayer object with aspect values expressed as radians

declination

The height of the light source (sun) expressed in degrees

direction

The direction (azimuth) of the light source (sun) expressed in degrees

filename

Character. Optional filename

...

Standard additional arguments for writing RasterLayer files

References

Horn, B.K.P., 1981. Hill shading and the reflectance map. Proceedings of the IEEE 69(1):14-47

See Also

slopeAspect

Examples

dem <- getData('alt', country='CHE')
slas <- slopeAspect(dem)
hill <- hillShade(slas[[1]], slas[[2]], 40, 270)
plot(hill, col=grey(0:100/100), legend=FALSE, main='Switzerland')
plot(dem, col=rainbow(25, alpha=0.35), add=TRUE)