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-boun...@r-project.org [mailto:r-help-boun...@r-project.org] On Behalf Of Greg Snow Sent: Tuesday, June 08, 2010 9:58 AM To: wenjun zheng; R-help@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.s...@imail.org 801.408.8111 > -----Original Message----- > From: r-help-boun...@r-project.org [mailto:r-help-boun...@r- > project.org] On Behalf Of wenjun zheng > Sent: Tuesday, June 08, 2010 7:45 AM > To: R-help@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@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@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@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.