samsr wrote: > Hi, > > I need to plot a matrix using image() such that negative values are easily > distinguishable from posittive values, while also maintaining a gradation in > color with magnitude. How can I set ranges for colors in order to achieve > this. Thanks. > Hi Sam,
This will give you red colors for the negative values, green for positive. x<-matrix(rnorm(100),nrow=10) cellcol<-matrix(rep("#000000",100),nrow=10) library(plotrix) cellcol[x<0]<-color.scale(x[x<0],c(1,0.8),c(0,0.5),0) cellcol[x>0]<-color.scale(x[x>0],0,c(0.7,0.8),c(0.5,0)) image(z=x,col=cellcol) 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.