[R] xYplot, lmline and abline

[Daniel E. Bunker]

Dear All,

I need to produce a multi-panel plot where:

1) groups within panels receive distinct symbols;
2) a linear regression is fit to the entire panel, not the individual 
groups;
3) a common abline is plotted in each panel.

Essentially I would like to merge the two plots below, but I can't seem 
to figure out how to call both lmline and abline, and also retain the 
grouping symbols. 

In addition, I have not yet figured out how to place the 'Key()' in the 
empty grid cell.

Please see the example code below.  Note that I am running R2.2.1 on 
windows.

Any help would be greatly appreciated.

Thanks for your time,

Dan


library(Hmisc)
windows(record=TRUE)

panelgrp=rep(LETTERS[1:3], 20)
sites=c(rep("d", 15), rep("e", 15), rep("f", 15), rep("g", 15))

data1=data.frame(panelgrp=factor(panelgrp), sites=factor(sites))
data1$pred=runif(60)
data1$resp=runif(60)

lmcoef=lm(resp~pred, data=data1[data1$panelgrp=="A",])

xYplot(resp~pred|panelgrp, groups=sites, data=data1, pch=c(1,2,3,4),
        abline=list(a=lmcoef$coefficients[1], b=lmcoef$coefficients[2], 
lty=2))
    Key()

xYplot(resp ~ pred|panelgrp, groups=sites, pch=c(1,2,3,4),
    data=data1,
       panel = function(x, y) {
        panel.xyplot(x,y)
           panel.lmline(x,y, span=1)
       }
    )





-- 
Daniel E. Bunker
BioMERGE Associate Director
Post-Doctoral Research Scientist
Columbia University
Department of Ecology, Evolution and Environmental Biology
1200 Amsterdam Avenue
New York, NY 10027-5557

deb37ATcolumbiaDOTedu
212-851-1888 phone
212-854-8188 fax