Plot with two Y axes : confidence intervals

Question

I am trying to plot several points with error bars, with two y axes. However at every call of the plotCI or errbar functions, a new plot is initialized - with or without par(ne

Answer 1

Use add=TRUE,

If FALSE (default), create a new plot; if TRUE, add error bars to an existing plot.

For example the last line becomes:

    plotCI(x,y=y2,uiw=delta,xaxt="n",gap=0,add=TRUE)

PS: hard to do this with ggplot2. take a look at this hadley code

EDIT

The user coordinate system is now redefined by specifying a new user setting. Here I do it manually.

plotCI(x,y=y1,uiw=delta,xaxt="n",gap=0)
axis(side=1,at=c(1:10),labels=rep("a",10),cex=0.7)
usr <- par("usr")
par(usr=c(usr[1:2], -1, 20))
plotCI(x,y=y2,uiw=delta,xaxt="n",gap=0,add=TRUE,col='red')
axis(4,col.ticks ='red')