I wrote some code to do this. It only works with 2 groups (that's all I needed), but could probably be generalized. It got my graph made, and I haven't needed a graph like this one again, so I never went back to really clean it up. It works by first plotting both sets of rectangles, then going back over the ones that had the first bar totally covered by the second. Hope this helps, Matt Wiener "f.back.front.hist" <- function(breaks, x1, x2, col1 = "gray50", col2 = "white", lwd = diff(range(mids))/20, xlab = "", ylab = "", leg.text = NULL, ...){ if(length(x1) != length(x2)) stop("x1 and x2 must have same length") if(length(x1) != length(breaks) - 1) stop("length of breaks must be 1 more than length of x1 and x2") plot.lim <- c(0, max(c(x1, x2))) mids <- 0.5 * (breaks[-1] + breaks[-length(breaks)]) plot(mids, pmax(x1, x2), col = par()$bg, lwd = lwd, ylim = plot.lim, xlab = xlab, ylab = ylab, cex.axis = 1.5, font.axis = 2, cex.lab = 1.5, font.lab = 2, ...) rect(breaks[-length(breaks)], 0, breaks[-1], x1, col = col1) rect(breaks[-length(breaks)], 0, breaks[-1], x2, col = col2) ind <- x1 < x2 rect(breaks[-length(breaks)][ind], 0, breaks[-1][ind], x1[ind] ,col = col1) if(!is.null(leg.text)) legend(mids[1], plot.lim[2], leg.text, fill = c(col1, col2), cex = 1.5) } -----Original Message----- From: r-help-bounces at stat.math.ethz.ch [mailto:r-help-bounces at stat.math.ethz.ch] On Behalf Of Jeff Miller Sent: Wednesday, June 28, 2006 4:21 PM To: 'Bill Shipley'; 'R help list' Subject: Re: [R] superimposing histograms con't [Broadcast] I was just thinking about this last night. I would like to do the same but WITH overlapping. For example, I graph 2 sets of count data. Say the bars for the 1`s overlap...I would like to show that with a different shading for the group that has the higher frequency. For example, it could be black up to a frequency of 5 followed by diagonal-dashes from 5-7 representing the higher frequency of a second group. Thank you, Jeff Miller -----Original Message----- From: r-help-bounces at stat.math.ethz.ch [mailto:r-help-bounces at stat.math.ethz.ch] On Behalf Of Bill Shipley Sent: Wednesday, June 28, 2006 3:54 PM To: R help list Subject: [R] superimposing histograms con't Earlier, I posted the following question: I want to superimpose histograms from three populations onto the same graph, changing the shading of the bars for each population. After consulting the help files and the archives I cannot find out how to do this (seemly) simple graph. To be clear, I want - a single x axis (from -3 to 18) - three groups of bars forming the histograms of each population (they will not overlap much, but this is a detail) - the bars from each histogram having different shadings or other visually distinguishing features. Gabor Grothendieck [ggrothendieck at gmail.com] pointed to some code to to this but I have found another way that works even easier. hist(x[sel1],xlim=c(a,b),ylim=c(A,B)) - this plots the histogram for the first group (indexed by sel1) but with an x axis and a y axis that spans the entire range. par(new=T) - to keep on the same graph hist(x[sel2],main=Null,xlab=NULL,ylab=NULL,axes=F) -superimposes the second histogram par(new=T) - to keep on the same graph hist(x[sel3],main=Null,xlab=NULL,ylab=NULL,axes=F) -superimposes the third histogram Bill Shipley North American Editor, Annals of Botany Editor, "Population and Community Biology" series, Springer Publishing Dipartement de biologie, Universiti de Sherbrooke, Sherbrooke (Quibec) J1K 2R1 CANADA Bill.Shipley at USherbrooke.ca http://callisto.si.usherb.ca:8080/bshipley/ [[alternative HTML version deleted]] ______________________________________________ R-help at stat.math.ethz.ch mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html