[R] How to break an axis?

[Bo Peng]

> Tom Mulholland has already pointed out that the plotrix package has an
> axis.break() function that will draw the break symbol. Your problem is a
> combination of plotting two disparate sets of data and getting the
> y-axis right. The following is one way to do it, just be careful that
> the ylim= and labels= arguments match up.
> 
> y1<-1+rnorm(10)/5
> y2<-3+rnorm(10)/5
> y3<-4+rnorm(10)/5
> y4<-397+rnorm(10)/5
> library(plotrix)
> plot(y1,ylim=c(0,10),axes=FALSE,main="Big range plot",ylab="Y values")
> points(y2)
> points(y3)
> box()
> axis(2,at=c(1,2,3,4,6,7,8,9),labels=c("1","2","3","4","396","397","398","399"))
> axis.break(2,5)
> par(new=TRUE)
> plot(y4,ylim=c(390,400),axes=FALSE,main="",ylab="",xlab="")
> 

Thank you very much for the real code. I did almost exactly the same
thing. I did not know the new=TRUE option so I used lines(y4-offset,
...). Anyway, the results are the same.

The left-right-axes solution is also very interesting. It is actually
better if the ranges of lines differ significantly.

Thank you again for the help.
Bo