[R] identify() and postscript output

[Michael Friendly]

In the following, I'm fitting a logistic regression model, and using 
car:::influencePlot.  When I run the latter with
output to the screen, it calls identify() that lets me label 
observations with large CookD.

However, if I use postscript() to get .eps output, identify() seems not 
to be called at all.  If instead, I
use dev.copy2eps() after getting output to the screen, the point labels 
do not appear in the resulting .eps
graph.  Why?  Is there a workaround?

library(vcd)
data(Arthritis)
# define Better
Arthritis$Better <- Arthritis$Improved > 'None'
arth.mod1 <- glm(Better ~ Age + Sex + Treatment , data=Arthritis, 
family='binomial')
library(car)
# influence plot
#postscript(file="arthritis-diag2.eps", paper="special", height=6, 
width=6, onefile=TRUE, horizontal=FALSE)
influencePlot(arth.mod1, main="Arthritis data: influencePlot")
#dev.off()

-Michael

-- 
Michael Friendly     Email: friendly AT yorku DOT ca 
Professor, Psychology Dept.
York University      Voice: 416 736-5115 x66249 Fax: 416 736-5814
4700 Keele Street    http://www.math.yorku.ca/SCS/friendly.html
Toronto, ONT  M3J 1P3 CANADA