The basic approach is: 1. call plot (sets up the main plotting) 2. call rect for each quadrant (or polygon if you prefer) 3. add the points with the points function (replotting any points covered by the rectangles) 4. add any additional notation (calling functions such as text, axis, etc.).
If you need the coordinates to use for your corners in step 2, look at ?par and scroll to the section on 'usr', or look at ?grconvertX in R2.7, or the cnvrt.coords function in the TeachingDemos package. If that does not do what you want, give us some more detail on what you are trying to accomplish. -- Gregory (Greg) L. Snow Ph.D. Statistical Data Center Intermountain Healthcare [EMAIL PROTECTED] (801) 408-8111 > -----Original Message----- > From: [EMAIL PROTECTED] > [mailto:[EMAIL PROTECTED] On Behalf Of tom soyer > Sent: Monday, April 07, 2008 2:02 PM > To: r-help@r-project.org > Subject: [R] How to add background color of a 2D chart by quadrant > > Hi, > > I have a 2D chart that is divided into four quadrants, I, II, III, IV: > > plot(1:10,ylim=c(0,10),xlim=c(0,10),type="n") > abline(v=5,h=5) > text(x=c(7.5,7.5,2.5,2.5),y=c(2.5,7.5,7.5,2.5),labels=c("I","I > I","III","IV")) > I would like to fill each quadrant with a background color > unique to the quadrant. Does anyone know how to do this in R? > > Thanks, > > -- > Tom > > [[alternative HTML version deleted]] > > ______________________________________________ > 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.
