From: Jim Brennan <jfbrennan_at_rogers.com>

Date: Fri 17 Jun 2005 - 13:17:26 EST

https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide!

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R-help@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 Received on Fri Jun 17 13:20:47 2005

Date: Fri 17 Jun 2005 - 13:17:26 EST

Object "vf" not found

R>version

arch i386 os mingw32 system i386, mingw32 status major 2 minor 1.0 year 2005 month 04 day 18 language R

-----Original Message-----

From: r-help-bounces@stat.math.ethz.ch

[mailto:r-help-bounces@stat.math.ethz.ch] On Behalf Of Gabor Grothendieck
Sent: June 16, 2005 10:56 PM

To: ramasamy@cancer.org.uk

Cc: R

Subject: Re: [R] how to plot density distribution with a arrow pointer?

On 6/16/05, Adaikalavan Ramasamy <ramasamy@cancer.org.uk> wrote:

> I am assuming that you want to do this empirically :

*>
**> x0 <- 0.899
**> x <- c( rnorm(6000), rnorm(4000, mean=3) )
**> plot( d <- density(x) )
**>
**> y0 <- approx( d$x, d$y, xout=x0 )$y # height at x0
**>
**> segments( x0, 0, x0, y0, col=2 )
**>
*

The following displays 4 arrows. Choose the one you like best:

# next 5 lines from previous post:

x0 <- 0.899

x <- c( rnorm(6000), rnorm(4000, mean=3) )
plot( d <- density(x) )

y0 <- approx( d$x, d$y, xout=x0 )$y # height at x0
# segments( x0, 0, x0, y0, col=2 )

points(x0,y0, pch=20, col="red") # red dot text(x0,y0, "\\da",vfont=vf, pos=3, col="green") text(x0,y0, "\\ua",vfont=vf, pos=1, col="red") yax <- par("usr")[3] # xaxis was drawn at this y level text(x0,yax, "\\ua", vfont=vf, pos=1, col="blue", xpd=TRUE, offset=0) text(x0,yax, "\\da", vfont=vf, pos=3, col="red", xpd=TRUE, offset=0)

The above uses xpd= which allows drawing outside of the main plot area and usr= which we need to get the position of the y coordinate of the boundary. It also uses the Hershey font for the arrow. Other arguments are described on the appropriate page. See:

?points ?text ?par # info on xpd= and usr= ?Hershey demo(Hershey) # examples of arrows ______________________________________________R-help@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

R-help@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 Received on Fri Jun 17 13:20:47 2005

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