[R] Lattice: Histogram in splom diagonals

[David Winsemius]

On Oct 7, 2010, at 9:04 AM, Alejo C.S. wrote:

> Dear list, I want to plot several variables with splom and in the main
> diagonal, instead of the  variable names, I'd like to plot an  
> histogram of
> corresponding variables. Searching I did not find the correct  
> syntax, only
> some tips in an old post in the list, but this comments help to plot  
> only
> density lines instead of histograms. I had some code, but it fails  
> to plot
> (I've commented the problematic lines):
>
>
> splom(iris[,1:4], panel = function(x, y, ...) {
>         panel.xyplot(x, y, ...)
> panel.lmline(x,y,...)
> }
> #        , diag.panel=function(x,...){
> #  panel.histogram(x,...)
> #        }
>
> )
>
> Thanks a lot in advance!
>

 From 2007 posting by Barnes (only return from RSiteSearch with  
modified Targets for "splom diag.panel histogram":

panel.hist.splom<-function(x, ...)
      {
          yrng <- current.panel.limits()$ylim
          h <- hist(x, plot = FALSE)
          breaks <- h$breaks; nB <- length(breaks)
          y <- h$counts; y <- yrng[1] + 0.95 * diff(yrng) * y / max(y)
          panel.rect(breaks[-nB], yrng[1], breaks[-1], y,  
col="cyan", ...)
      }
my.plot = function(data) {
   splom( ~data,
        lower.panel=function(x, y, ...) {
          panel.xyplot(x, y, ...)
          panel.lmline(x,y,...)},
        upper.panel=function(x, y, ...) {
          panel.xyplot(x, y, ...)
          panel.lmline(x,y,...)},
        diag.panel = panel.hist.splom)
}

my.plot(iris[,1:4])


David Winsemius, MD
West Hartford, CT