hillShade function

Hill shading

Compute hill shade from slope and aspect layers (both in radians). Slope and aspect can be computed with function terrain.

A hill shade layer is often used as a backdrop on top of which another, semi-transparent, layer is drawn.

hillShade(slope, aspect, angle=45, direction=0, filename='', normalize=FALSE, ...)

Arguments

• slope: RasterLayer object with slope values (in radians)
• aspect: RasterLayer object with aspect values (in radians)
• angle: The the elevation angle of the light source (sun), in degrees
• direction: The direction (azimuth) angle of the light source (sun), in degrees
• filename: Character. Optional filename
• normalize: Logical. If TRUE, values below zero are set to zero and the results are multiplied with 255
• ...: Standard additional arguments for writing RasterLayer files

See Also

terrain

Author(s)

Andrew Bevan, Robert J. Hijmans

References

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