[R] Plotting points on line graphs using xYplot in Hmisc

[John Poulsen]

Hello,

I am using xYplot to plot lines with confidence bands (see test 
example below).  I would like to add a single point with 
confidence bars to each graph (coordinates of the points below: 
px, py, pxlow, etc...).  I tried playing with 
panel=panel.superpose, but failed to get it to work.  Any ideas on 
how to add these points to the graphs?

Thanks for your help,
John


## Test example

x1=seq(1,30,0.5)
y1=x1^2
y2=10*(x1^2)
ycomb=c(y1,y2)
y.up=ycomb+0.1*ycomb
y.low=ycomb-0.1*ycomb
grp=rep(c("Anls","Plts"),each=length(x1))
dat=as.data.frame(cbind(ycomb, y.up, y.low, 
rep(x1,2)),stringsAsFactors=F)
colnames(dat)=c("ycomb","y.up","y.low","x1")
py=c(200,2000); pylow=c(190,1900); pyhi=c(210,2100)
px=c(0,0); pxlow=c(0,0); pxhi=c(0,0)

with(dat,xYplot(Cbind(ycomb, y.up, y.low)~x1|factor(grp),
     data=dat,type="l", method="filled bands", col.fill="light 
grey",
     
scales=list(y=list(relation="free"),x=list(alternating=c(1,1,1))),
     ylim=list(c(0,1200),c(0,10000)),
     strip=strip.custom(factor.levels=c(expression("Anls 
km"^2),expression("Plants km"^2)))))

-------------------------------
John Poulsen
223 Bartram Hall PO Box 118525
University of Florida
Gainesville, FL 32611-8525