plotRGB
Red-Green-Blue plot of a multi-layered Raster object
Make a Red-Green-Blue plot based on three layers (in a RasterBrick or RasterStack). Three layers (sometimes referred to as "bands" because they may represent different bandwidths in the electromagnetic spectrum) are combined such that they represent the red, green and blue channel. This function can be used to make 'true (or false) color images' from Landsat and other multi-band satellite images.
Usage
# S4 method for RasterStackBrick
plotRGB(x, r=1, g=2, b=3, scale, maxpixels=500000, stretch=NULL,
ext=NULL, interpolate=FALSE, colNA='white', alpha, bgalpha, addfun=NULL, zlim=NULL,
zlimcol=NULL, axes=FALSE, xlab='', ylab='', asp=NULL, add=FALSE, margins=FALSE, ...)Arguments
- x
RasterBrick or RasterStack
- r
integer. Index of the Red channel, between 1 and nlayers(x)
- g
integer. Index of the Green channel, between 1 and nlayers(x)
- b
integer. Index of the Blue channel, between 1 and nlayers(x)
- scale
integer. Maximum (possible) value in the three channels. Defaults to 255 or to the maximum value of
xif that is known and larger than 255- maxpixels
integer > 0. Maximum number of pixels to use
- stretch
character. Option to stretch the values to increase the contrast of the image: "lin" or "hist"
- ext
An
Extentobject to zoom in to a region of interest (seedrawExtent)- interpolate
logical. If
TRUE, interpolate the image when drawing- colNA
color for the background (
NAvalues)- alpha
transparency. Integer between 0 (transparent) and 255 (opaque)
- bgalpha
Background transparency. Integer between 0 (transparent) and 255 (opaque)
- addfun
Function to add additional items such as points or polygons to the plot (map). See
plot- zlim
numeric vector of length 2. Range of values to plot (optional)
- zlimcol
If
NULLthe values outside the range of zlim get the color of the extremes of the range. If zlimcol has any other value, the values outside the zlim range get the color ofNAvalues (see colNA)- axes
logical. If
TRUEaxes are drawn (and arguments such asmain="title"will be honored)- xlab
character. Label of x-axis
- ylab
character. Label of y-axis
- asp
numeric. Aspect (ratio of x and y. If NULL, and appropriate value is computed to match data for the longitude/latitude coordinate reference system, and 1 for planar coordinate reference systems
- add
logical. If
TRUEadd values to current plot- margins
logical. If
TRUEstandard whitespace margins are used. IfFALSE, graphics::par(plt=c(0,1,0,1)) is used- ...
graphical parameters as in
plotorrasterImage
See Also
Examples
# NOT RUN {
b <- brick(system.file("external/rlogo.grd", package="raster"))
plotRGB(b)
plotRGB(b, 3, 2, 1)
plotRGB(b, 3, 2, 1, stretch='hist')
# }