[R] adding horizontal lines to a trellis plot

[Bert Gunter]

Please read about panel functions in ?xyplot and ?panel.abline

In particular, you do this sort of thing in panel functions where you must
use grid graphics functions or various lattice forms (wrappers) thereof. The
standard graphics constructions will not work (as you found out).Suggested
reference: Deepayan Sarkar's new book on lattice graphics.

-- Bert Gunter
Genentech

-----Original Message-----
From: r-help-bounces at r-project.org [mailto:r-help-bounces at r-project.org] On
Behalf Of Blanchard, Suzette
Sent: Thursday, June 12, 2008 10:52 AM
To: r-help at r-project.org
Subject: [R] adding horizontal lines to a trellis plot

I would like to add two horizontal lines representing acceptible drug levels
to a trellis plot.
I tried using abline and I get an error that "plot.new has not been called."
See below.  
 
xyplot(FK~WEEK|Event1/MRN, data=FKdat.o1)
abline(h=5)
abline(h=10)
Error in int_abline(a = a, b = b, h = h, v = v, untf = untf, ...) : 
  plot.new has not been called yet

Any help that can be provided on how to do this would be appreciated.
 
Best,
Suzette 
 
Suzette Blanchard, Ph.D.
Assistant Professor, Dept. of Biostatistics
City of Hope
1500 East Duarte Rd
Duarte, CA 91010-3000
ph: (626) 256-4673 ext:64446
sblanchard at coh.org
 


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