R help - Apr 2006 - Legend in the outer margin

Dear Rs

I have a 3x3 multiple plot. I would like to have a overall legend in
the outer right margin.
From the help archive, I found that it can be done by setting
par(xpd=NA). However, I couldn't find the correct values
for x and y co-ordinates for the legend. Please find the code snippet below:

par(mfrow=c(3,3), mar=c(4,4,0.9,0.5), oma=c(1,2,2,4),cex.main=1.1)

  *postscript(*file=epsfile,onefile=FALSE,horizontal=TRUE*)*

/* some plotting */

par(xpd=NA)

legend(legend=c("2h-opt Exact","1-shift Exact","2p-opt
Exact"),
lty=c("solid","dashed","dotdash"),lwd=c(2,2,2),col=c("red","green","black"),
bty="n",cex=0.8)

Thanks in advance
Prasanna

	[[alternative HTML version deleted]]

Prasanna wrote:
> Dear Rs
> 
> I have a 3x3 multiple plot. I would like to have a overall legend in
> the outer right margin.
>>From the help archive, I found that it can be done by setting
> par(xpd=NA). However, I couldn't find the correct values
> for x and y co-ordinates for the legend. Please find the code snippet
below:
> 
> par(mfrow=c(3,3), mar=c(4,4,0.9,0.5), oma=c(1,2,2,4),cex.main=1.1)
> 
>   *postscript(*file=epsfile,onefile=FALSE,horizontal=TRUE*)*
> 
> /* some plotting */
> 
> par(xpd=NA)
You get the user coordinates of the plotting region by
   par("usr")
Now simply make the legend right of that plotting region, e.g. with
x corrdinates at
   par("usr")[2] + epsilon
and y coordinates at
   mean(par("usr")[3:4])

Uwe Ligges


> legend(legend=c("2h-opt Exact","1-shift
Exact","2p-opt Exact"),
>
lty=c("solid","dashed","dotdash"),lwd=c(2,2,2),col=c("red","green","black"),
> bty="n",cex=0.8)
> 
> Thanks in advance
> Prasanna
> 
> 	[[alternative HTML version deleted]]
> 
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> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide!
http://www.R-project.org/posting-guide.html

The cnvrt.coords function in the TeachingDemos package may be of help.
Here is an example of possible use (just change the .9 and .7 to where
ever on the page you want the legend):

par(mfrow=c(3,3), mar=c(4,4,0.9,0.5), oma=c(1,2,2,4),cex.main=1.1)

for (i in 1:9){
	x <- runif(25,1,10)
	y <- 3+ i*x + rnorm(25)
	plot(x,y)
}

par(xpd=NA)

tmp <- cnvrt.coords(.9,.7, 'tdev')$usr

legend(tmp,legend=c("2h-opt Exact","1-shift
Exact","2p-opt Exact"),
lty=c("solid","dashed","dotdash"),lwd=c(2,2,2),col=c("red","green","blac
k"),
bty="n",cex=0.8)

-- 
Gregory (Greg) L. Snow Ph.D.
Statistical Data Center
Intermountain Healthcare
greg.snow at intermountainmail.org
(801) 408-8111
 
 
> -----Original Message-----
> From: r-help-bounces at stat.math.ethz.ch 
> [mailto:r-help-bounces at stat.math.ethz.ch] On Behalf Of Dieter Menne
> Sent: Monday, April 10, 2006 7:40 AM
> To: r-help at stat.math.ethz.ch
> Subject: Re: [R] Legend in the outer margin
> 
> Uwe Ligges <ligges <at> statistik.uni-dortmund.de> writes:
> 
> > You get the user coordinates of the plotting region by
> >    par("usr")
> > Now simply make the legend right of that plotting region, 
> e.g. with x 
> > corrdinates at
>     par("usr")[2] + epsilon
> > and y coordinates at
> >    mean(par("usr")[3:4])
> 
> I always found it ugly that this depends on the last plotted 
> figure in an array, but I wanted to position my legend 
> independent of it at an absolute position in device space. 
> What's the best way to achieve this?
> 
> par(mfrow=c(3,3), mar=c(4,4,0.9,0.5), 
>    oma=c(5,2,5,10),cex.main=1.1)
> 
> n=7 # Legend should be positioned independent of n for (i in 1:n){
>   plot(rnorm(20),ylim=c(-3,3))
> }
> 
> # ... just the idea
> reset_to_01_coordinates()
> par(xpd=NA)
> leg = legend(0.9,0.5, # << Should be seen as absolute in 0/1 
> coords c("2h-opt Exact","1-shift Exact","2p-opt
Exact"),
>
lty=c("solid","dashed","dotdash"),lwd=c(2,2,2),
> col=c("red","green","black"),
> bty="n",cex=0.8)
> 
> 
> Dieter
> 
> ______________________________________________
> R-help at stat.math.ethz.ch mailing list
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide! 
> http://www.R-project.org/posting-guide.html
>