[R] Symbols in R

[Bert Gunter]

Mount soapbox; begin rant {

... However I think it should be added that rarely does this work with more
than about a half dozen different symbols: a viewer of a graphic simply
cannot keep the distinctions straight -- or often even decode them. Using
color to distinguish groups is typically more effective (there is actual
research to justify this), but of course one then runs up against the
subjectivity of color perception: aside from the obvious (and fairly common)
red-green color blindness issue, there's also the problem that people
perceive different colors differently, making some look more prominent than
others, which may interfere with the decoding of the graphical features.

In general, in the age of Excel graphics, I would argue that the use of
point/line characteristics like shape, fill, and color that are decoded
through legends are much overused and frequently result in visual puzzles
and illusions, which is the opposite of what a good data graphic should do.

An often better approach is the use of small multiples -- trellis graphics
-- for which the lattice and ggplot packages provide excellent
functionality.

} end rant; dismount soapbox

Cheers,
Bert

Bert Gunter
Genentech Nonclinical Biostatistics
 
 
-----Original Message-----
From: r-help-bounces at r-project.org [mailto:r-help-bounces at r-project.org] On
Behalf Of Greg Snow
Sent: Tuesday, June 08, 2010 9:58 AM
To: wenjun zheng; R-help at r-project.org
Subject: Re: [R] Symbols in R

The my.symbols function (TeachingDemos package) allows for defining your own
symbols to use in plots using base graphics (see ms.filled.polygon for an
example), there is also panel.my.symbols which works with lattice (possibly
with general grid, but I have not tested it that way).

Those may give you a starting point.

-- 
Gregory (Greg) L. Snow Ph.D.
Statistical Data Center
Intermountain Healthcare
greg.snow at imail.org
801.408.8111


> -----Original Message-----
> From: r-help-bounces at r-project.org [mailto:r-help-bounces at r-
> project.org] On Behalf Of wenjun zheng
> Sent: Tuesday, June 08, 2010 7:45 AM
> To: R-help at r-project.org
> Subject: [R] Symbols in R
> 
> Hi R Users,
> 
>     I want to distinguish different condition by different symbols by
> pch in
> function grid.points, but the symbols needed should be with solid or
> hollow,
> in this way only 21 to 25 in pch worked, is there any other symbols
> could be
> used like this? or does it exist any other way to draw symbols?
> 
>     Any suggestions will be appreciated.
> 
> Best regards.
> 
> --
> Wenjun
> 
> 	[[alternative HTML version deleted]]
> 
> ______________________________________________
> R-help at r-project.org mailing list
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide http://www.R-project.org/posting-
> guide.html
> and provide commented, minimal, self-contained, reproducible code.

______________________________________________
R-help at r-project.org mailing list
https://stat.ethz.ch/mailman/listinfo/r-help
PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.