Please check the current sources (R-2.1.0 alpha).
pch = NA is now documented under points(), where all the other values are,
and pch="" is now equivalent.
On Tue, 22 Mar 2005 arnima@u.washington.edu wrote:
> I'd like to suggest changes to three help pages, regarding the use of
> pch=NA to suppress plotting symbols. See below.
>
> Arni
>
> R 2.0.1 on WinXP
>
>
>
> ==> help(bxp)
> ==>
> The argument outpch=" " needs to be replaced with outpch=NA in
two places.
>
> I actually wrote this part of the documentation myself at one point, but
> have now realized that pch=NA and pch=" " are not the same:
>
> x <- split(rlnorm(26e4), letters)
> ## NA generates small file
> postscript("na.ps"); boxplot(x,outpch=NA); dev.off()
> ## Space generates large file
> postscript("space.ps"); boxplot(x,outpch=" ");
dev.off()
space was I am sure intended here.
>
>
>
> ==> help(par)
> help(points)
> ==>
> Please specify that pch=NA can be used to suppress plotting symbols.
>
> I'm aware of type="n", but pch=NA can be a useful feature
inside functions
> and should be documented somewhere. Other negative-sounding values
> (-1,0,NULL,""," ") generate different results, and only
pch=NA does the
> job properly.
--
Brian D. Ripley, ripley@stats.ox.ac.uk
Professor of Applied Statistics, http://www.stats.ox.ac.uk/~ripley/
University of Oxford, Tel: +44 1865 272861 (self)
1 South Parks Road, +44 1865 272866 (PA)
Oxford OX1 3TG, UK Fax: +44 1865 272595