terra (version 1.5-21)

RGB: Layers representing colors

Description

With RGB you can get or set the layers to be used as Red, Green and Blue when plotting a SpatRaster. Currently, a benefit of this is that plot will send the object to plotRGB

With colorize you can convert a three-layer RGB SpatRaster into other color spaces. You can also convert it into a single-layer SpatRaster with a color-table.

Usage

# S4 method for SpatRaster
RGB(x)
# S4 method for SpatRaster
RGB(x)<-value
# S4 method for SpatRaster
colorize(x, to="hsv", alpha=FALSE, stretch=NULL, 
	grays=FALSE, NAzero=FALSE, filename="", overwrite=FALSE, ...)

Arguments

x

SpatRaster

value

vector of three (or four) positive integers indicating the layers that are red, green and blue (and optionally a fourth transparancy layer). Or NULL to remove the RGB settings

to

character. The color space to transform the values to. If x has RGB set, you can transform these to "hsv", "hsi" and "hsl", or use "col" to create a single layer with a color table. You can also use "rgb" to backtransform to RGB

alpha

logical. Should an alpha (transparancy) channel be included? Only used if x has a color-table and to="rgb"

stretch

character. Option to stretch the values to increase contrast: "lin" (linear) or "hist" (histogram). Only used for transforming RGB to col

grays

logical. If TRUE, a gray-scale color-table is created. Only used for transforming RGB to col

NAzero

logical. If TRUE, NAs are treated as zeros such that a color can be returned if at least one of the three channels has a value. Only used for transforming RGB to ("col")

filename

character. Output filename

overwrite

logical. If TRUE, filename is overwritten

...

additional arguments for writing files as in writeRaster

Examples

# NOT RUN {
r <- rast(system.file("ex/logo.tif", package="terra"))   
plot(r)
RGB(r) <- NULL
plot(r)
RGB(r) <- c(3,1,2)
plot(r)

RGB(r) <- 1:3
x <- colorize(r, "col")
y <- colorize(r, "hsv")
z <- colorize(y, "rgb")
# }