With RGB you can get or set the layers to be used as Red, Green and Blue when plotting a SpatRaster. Currently, the sole benefit of this is that plot will send the object to plotRGB
With RGB2col you can convert a three-layer RGB SpatRaster into a single-layer SpatRaster with a color-table.
vector of three positive integers indicating the layers that are red, green and blue. Or NULL to remove the RGB settings. With rgb2coltab, this can be missing if RGB is not NULL
stretch
character. Option to stretch the values to increase contrast: "lin" (linear) or "hist" (histogram)
grays
logical. If TRUE, a gray-scale color-table is created
filename
character. Output filename
overwrite
logical. If TRUE, filename is overwritten
...
additional arguments for writing files as in writeRaster