Rajarshi Guha asked: > > Hi, I'd like to use a custom color sequence (black - low values, > green - high values) in am image() plot. While I can specify colors > (say a sequence of grays) to the col argument, the ordering is > getting messed up. I have two questions: > > 1. How can I get a sequence of say 256 colors starting from black > and ending in green? > 2. How is this specified to image() such that it uses the colors in the > proper ordering? > Does
image(x, y, z) (whatever are the x, y and z) work correctly? If so, probably this is what you want: image(x, y, z, nlevels=256, col=rgb(0, seq(0, 1, length=256), 0)) Explanation: rgb(0, seq(0, 1, length=256), 0) creates a vector of colours that begin with "black" = "#00000" and ends up with "green" = "#00FF00". Parameter nlevels = 256 forces the image to use all colours. Alberto Monteiro ______________________________________________ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
