On 10/17/2009 01:25 AM, Rajarshi Guha wrote:
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?
Hi Rajarshi,
Adding to what Albert wrote, if you mean that you want black to gray and
then gray to green, you can get it by creating two sequences of colors
and then joining them together:
ccolors<-c(rgb(seq(0,0.5,length.out=128),
seq(0,0.5,length.out=128),seq(0,0.5,length.out=128)),
rgb(seq(0.5,0,length.out=128),seq(0.5,1,length.out=128),
seq(0.5,0,length.out=128)))
image(...,col=ccolors,...)
See the examples in "color2D.matplot" for more information.
Jim
______________________________________________
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.
