Fwd: Re: [R] legend() with option adj=1

[Frank E Harrell Jr]

On Thu, 5 Jun 2003 07:20:11 -0700
"Anna  H. Pryor" <anna at ptolemy.arc.nasa.gov> wrote:

> Is there a simpler way then the solution to the one that was posted here?  I'm 
> not very proficient with legend, and I don't understand this solution.   All 
> I have is two or more lines on one plot that I want to put a legend on and I 
> can't figure out how to do it from the examples.  Can you give a very simple 
> example? It does not have to be fancy!!  I have never worked with a package 
> where the legend was not automatic.
> 
> 
> 
> ----------  Forwarded Message  ----------
> 
> Subject: Re: [R] legend() with option adj=1
> Date: Wed, 21 May 2003 09:19:11 +0200
> From: Uwe Ligges <ligges at statistik.uni-dortmund.de>
> To: Jerome Asselin <jerome at hivnet.ubc.ca>
> Cc: r-help at stat.math.ethz.ch
> 
> Jerome Asselin wrote:
> > Hi there,
> >
> > I want to justify to right the text of my legend. Consider this short
> > reproducable example.
> >
> > x <- 1:5
> > y1 <- 1/x
> > y2 <- 2/x
> > plot(rep(x,2),c(y1,y2),type="n",xlab="x",ylab="y")
> > lines(x,y1)
> > lines(x,y2,lty=2)
> > legend(5,2,c("1,000","1,000,000"),lty=1:2,xjust=1,yjust=1)
> > legend(5,1.5,c("1,000","1,000,000"),lty=1:2,xjust=1,yjust=1,adj=1)
> >
. . .
> 
> Uwe Ligges

Here is an alternative to consider.  In plots such as this I like to label the curves where they are most separated and avoid legends altogether (as well as usually avoiding the need for different line types, unless curves intertwine):

x <- 1:5
y <- 1/x
y2 <- 2/x
w <- list('1/x'=list(x=x,y=y),'2/x'=list(x=x,y=y2))
library(Hmisc) # see http://hesweb1.med.virginia.edu/biostat/s/Hmisc.html
labcurve(w, pl=TRUE, offset=.1)

Or put a legend in the most empty region of the graph:

labcurve(w, pl=TRUE, lty=c(2,1), lwd=c(1,3), col=gray(c(0,.7)), keys='lines',
         xlab=expression(chi))  
# lty only for demonstration - omit that for this example.  Thick gray scale # lines are excellent for step functions

Or use same line types but put symbols every so often (point.inc= to override default spacing; this works well for overlapping step functions also):

labcurve(w, pl=TRUE, keys=1:2)  # uses pch=1:2

---
Frank E Harrell Jr              Prof. of Biostatistics & Statistics
Div. of Biostatistics & Epidem. Dept. of Health Evaluation Sciences
U. Virginia School of Medicine  http://hesweb1.med.virginia.edu/biostat