[R] shared axes in multipanel plot

[Jennifer Young]

splendid!

This worked well, but there are two oddities that I can't resolve.

1. In the real data, the "baseline" is a cumulative probability plot (from
simulations) rather than the straight line.  The panel.lines plots this
curve, but seems to join the first and last points together.
panel.points(x, baseline, type="l") did the same.
I checked that the vector is indeed sorted properly, so I'm not sure why
it should connect the first point to the last.

2. The screens are correctly labeled, but in the wrong order (left to
right, top to bottom: 3,4,1,2). Is this easily corrected?

I've been cowardly avoiding learning xyplot() so thanks for the jumpstart!

> 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.
>>
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>>
>