[R] adding text in (pair) panels (splom)

Paul Murrell p.murrell at auckland.ac.nz
Sat Apr 10 04:39:26 CEST 2004


Patrick Giraudoux wrote:
> Hi,
> I would like to add text in each panel got from the following:
> splom(~Cs5bis,
> panel=function(x,y,...){
> panel.xyplot(x,y,...)
> panel.abline(lm(y~x),...)
> })
> This could be a correlation coefficient or the statistical significance of the correlation or both, or a star if p < 0.05, etc...
> The function text() is useless (probably because I cannot pass appropriates coordinates in each panel). Googling the R-archives, I
> have found only one hint of Andy Liaw relating a rather complex (to me) script within a home-made panel.myfitline() function.
> Is there a simple way to add text in panels created eg with:
> panel=function(x,y,...){
> panel.xyplot(x,y,...)
> panel.abline(lm(y~x),...)
> })

text() is useless because splom is a lattice function and lattice is 
based on grid.  To add text in a panel you could use lattice's ltext(), 
but I think the best way would be to use grid.text() as below.  This 
example draws the correlation coefficient 1mm in from the top-left 
corner of the panel.

           grid.text(round(cor(x, y), 2),
             x=unit(1, "mm"), y=unit(1, "npc") - unit(1, "mm"),
             just=c("left", "top"))

Does that do what you want?

Dr Paul Murrell
Department of Statistics
The University of Auckland
Private Bag 92019
New Zealand
64 9 3737599 x85392
paul at stat.auckland.ac.nz

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