[R] errorbar il lattice plot

[Federico Calboli]

Hi Everyone,

I would like to add errorbars to a lattice plot. I already have a function that 
adds error bars to a plot (originally written by George Gilchrist) which takes 
as arguments the coordinates of the point and then the size of the error bar. I 
would like to integrate it in my lattice code but I seem to be stumped.

I can put the error bar function inside my code as if it were a panel function, 
but it then sits there quite unused. I am not even clear how what data object to 
put the standard errors for the thing to work...

My code (the version that at least draws a plot):

xyplot(inbreeding~generations|breeds, data = trellisplot, type = 'l', layout = 
c(2,5), col = 'black', lwd = 3,
errbar = function(x, y, err, down = T, width = 0.005, lwd = 1, plot = T, 
colour="black")
{
   up <- y + err
   dn <- y - err
   x.range <- max(x) - min(x)
   wid.lf <- x - (x.range * width)
   wid.rt <- x + (x.range * width)
   if(plot == F) {
     return(data.frame(x, up, dn))
   }
   else {
     if(down == F) {
       segments(x, up, x, y, lwd = lwd, lty = 1, col = colour)
       segments(wid.lf, up, wid.rt, up, lwd = lwd, lty = 1, col = colour)
     }
     else {
       segments(x, up, x, dn, lwd = lwd, lty = 1, col = colour)
       segments(wid.lf, up, wid.rt, up, lwd = lwd, lty = 1, col = colour)
       segments(wid.lf, dn, wid.rt, dn, lwd = lwd, lty = 1, col = colour)
     }
     invisible(data.frame(x, up, dn))
   }
}
)


Regards,

Federico Calboli

-- 
Federico C. F. Calboli
Department of Epidemiology and Public Health
Imperial College, St Mary's Campus
Norfolk Place, London W2 1PG

Tel  +44 (0)20 7594 1602     Fax (+44) 020 7594 3193

f.calboli [.a.t] imperial.ac.uk
f.calboli [.a.t] gmail.com