R help - Dec 2009 - shared axes in multipanel plot

Hello

I've created a function to make a plot with multiple pannels from columns
of data that are created in a previous function.  In the example below the
number of columns is 8, giving 4 pannels, but in general it takes data
with any number of columns and figures out a nice layout.

The panels all have the same axes, and so I wonder what functions are
avialable to create axes only on the left and bottom of the whole plot
rather than each pannel.
I'd really like a generic way to do this for any number of plots, but was
even having trouble figuring out how to do it manually for this example;
How are pannels referred to, in a layout context?
That is, how do I say,

if(current.pannel==4) {do stuff}

Here's a simple version of the code.

baseline <- (1:20)/20    #example data
dat1 <- matrix(baseline,20,8)
dat <- dat1+matrix(rnorm(20*8)/30, 20,8)

nstrat <- ncol(dat)
rows <- ceiling(nstrat/4)
layout(matrix(1:(rows*2), rows, 2, T))
par(oma=c(4,4,3,1))
par(mar=c(1,1,0,1))
for(i in which(1:nstrat%%2!=0)){
    plot(baseline, type="l", col="grey", lwd=2,
            xlab="", ylab="", ylim=c(0,1), xaxt='n',
yaxt='n')
    axis(1, labels=F); axis(2, labels=F)
    points(dat[,i], type="l", lty=2)
    points(dat[,i+1], type="l", lty=2)
}



Thank you muchly
Jennifer Young

PS: I am a subscriber, but can't for the life of me figure out how to send
an email while logged in so that the moderators don't have to take the
time to read it over.  I always get the "please wait while we check it
over" email.  Likely I'm being dumb.

Try this using xyplot.zoo in the zoo package.  We define the baseline
and a panel function.   The panel function just performs the default
action to display the graphs and adds the baseline.   The screens
variable is 1,1,2,2,3,3,4,4.  We create a zoo object from dat and use
screens to name the columns according to their group.  Finally we call
xyplot.zoo passing it screens so that the successive columns go in the
indicated panels and also passing the other items.  See ?xyplot.zoo in
zoo and ?xyplot in lattice.

library(zoo)
library(lattice)

baseline <- 1:nrow(dat)/nrow(dat)
pnl <- function(x, ...) {
	panel.plot.default(x, ...)
	panel.lines(x, baseline, lwd = 2, col = grey(0.5))
}
nc <- ncol(dat)
screens <- rep(1:(nc/2), each = 2)
z <- zoo(dat)
colnames(z) <- paste("Group", screens)
xyplot(z, screens = screens , layout = c(2, 2), col = "black", lty 2,
scales = list(y = list(relation = "same")), panel = pnl)


On Fri, Dec 11, 2009 at 10:02 AM, Jennifer Young
<Jennifer.Young at math.mcmaster.ca> wrote:
> Hello
>
> I've created a function to make a plot with multiple pannels from
columns
> of data that are created in a previous function. ?In the example below the
> number of columns is 8, giving 4 pannels, but in general it takes data
> with any number of columns and figures out a nice layout.
>
> The panels all have the same axes, and so I wonder what functions are
> avialable to create axes only on the left and bottom of the whole plot
> rather than each pannel.
> I'd really like a generic way to do this for any number of plots, but
was
> even having trouble figuring out how to do it manually for this example;
> How are pannels referred to, in a layout context?
> That is, how do I say,
>
> if(current.pannel==4) {do stuff}
>
> Here's a simple version of the code.
>
> baseline <- (1:20)/20 ? ?#example data
> dat1 <- matrix(baseline,20,8)
> dat <- dat1+matrix(rnorm(20*8)/30, 20,8)
>
> nstrat <- ncol(dat)
> rows <- ceiling(nstrat/4)
> layout(matrix(1:(rows*2), rows, 2, T))
> par(oma=c(4,4,3,1))
> par(mar=c(1,1,0,1))
> for(i in which(1:nstrat%%2!=0)){
> ? ?plot(baseline, type="l", col="grey", lwd=2,
> ? ? ? ? ? ?xlab="", ylab="", ylim=c(0,1),
xaxt='n', yaxt='n')
> ? ?axis(1, labels=F); axis(2, labels=F)
> ? ?points(dat[,i], type="l", lty=2)
> ? ?points(dat[,i+1], type="l", lty=2)
> }
>
>
>
> Thank you muchly
> Jennifer Young
>
> PS: I am a subscriber, but can't for the life of me figure out how to
send
> an email while logged in so that the moderators don't have to take the
> time to read it over. ?I always get the "please wait while we check it
> over" email. ?Likely I'm being dumb.
>
> ______________________________________________
> R-help at 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.
>