[R] superimposing histograms con't [Broadcast]

Wiener, Matthew matthew_wiener at merck.com
Wed Jun 28 22:51:35 CEST 2006

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)
      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
par(new=T)  - to keep on the same graph
hist(x[sel3],main=Null,xlab=NULL,ylab=NULL,axes=F) -superimposes the third

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




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