Lattice graphics can do that: library(lattice) xyplot(0:20 ~ 0:20, alpha = 0:20/20, col = "red", pch = 19, cex = 5)
Google for HTML colors to find out more about the hex codes you are referring to. On Wed, Aug 5, 2009 at 11:48 PM, per freem<perfr...@gmail.com> wrote: > hi all, > > i have a simple scatter plot, and i'd like to make it so the scatter > plot colors are slightly transparent. i see in a previous post that > someone mentioned the "alpha" parameter, but i am not sure how it can > be used with the 'plot' function [*]. > > for example, suppose i have: > > plot(mydata$column1, mydata$column2, col="red", cex=1) > > i now want to make it so the color of these points (in this case red) > is slightly transparent, which will make overlap between them very > obvious. i realize that hexbin and other density plot methods are used > to make this, but i am using it for a different purpose, and so i just > want the points to be transparent without any binning or shading. > > a previous poster suggested: > > plot( rnorm(1000), rnorm(1000), col="#0000ff22", pch=16,cex=3) > > but i don't understand this color notation. is there any way to pass > in the usual col="colorname" argument and then tweak that color's > transparency? > > thank you. > > https://stat.ethz.ch/pipermail/r-help/2007-October/142934.html > > ______________________________________________ > 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. > ______________________________________________ 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.