Hi, Is there any way to take one color of each color family from a color palettes like rainbow? For ex, if there are different blues differentiated by intensity, hue etc, taking one of them. In this case, when using rainbow(n), then how to select 1 color of each family, for ex 1 blue, 1 red etc? It doesn't matter which intensity, hue etc is taken as long as 1 color from each family is taken. Thanks Carol [[alternative HTML version deleted]]
?rainbow ?col2rgb rainbow(8) col2rgb(rainbow(8)[5]) col2rgb(rainbow(8)[5])[1] col2rgb(rainbow(8)[5])[2] col2rgb(rainbow(8)[5])[3] On Fri, Aug 8, 2014 at 6:26 AM, carol white <wht_crl at yahoo.com> wrote:> Hi, > Is there any way to take one color of each color family from a color palettes like rainbow? For ex, if there are different blues differentiated by intensity, hue etc, taking one of them. In this case, when using rainbow(n), then how to select 1 color of each family, for ex 1 blue, 1 red etc? It doesn't matter which intensity, hue etc is taken as long as 1 color from each family is taken. > > > Thanks > > Carol > > [[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.
You might take a look at the RColorBrewer package. Sarah On Fri, Aug 8, 2014 at 9:26 AM, carol white <wht_crl at yahoo.com> wrote:> Hi, > Is there any way to take one color of each color family from a color palettes like rainbow? For ex, if there are different blues differentiated by intensity, hue etc, taking one of them. In this case, when using rainbow(n), then how to select 1 color of each family, for ex 1 blue, 1 red etc? It doesn't matter which intensity, hue etc is taken as long as 1 color from each family is taken. > > > Thanks > > Carol-- Sarah Goslee http://www.functionaldiversity.org
I think your question is too vague to answer since we don't know what you
are trying to do or how many colors you need. The easy answer is that you
don't need to use rainbow() at all, just use color names:
mycolors <- c("red", "green", "blue",
"violet")
and you will have one of each. For example, col=mycolors(2) will plot using
green (and so will col="green"). There are lots of color names in R:
> length(colors(distinct=TRUE))
[1] 502
The longer answer is that there are many color palettes and ways of selecting,
manipulating, and choosing colors. The built in functions include palettes such
as rainbow, heat.colors, terrain.colors, topo.colors, cm.colors, and gray and
ways of specifying colors (in addition to using names) including rgb, hsv, and
hcl. In addition, there are several packages for creating color palettes
including RColorBrewer, colortools, colorspace, and munsell.
-------------------------------------
David L Carlson
Department of Anthropology
Texas A&M University
College Station, TX 77840-4352
-----Original Message-----
From: r-help-bounces at r-project.org [mailto:r-help-bounces at r-project.org]
On Behalf Of carol white
Sent: Friday, August 8, 2014 8:27 AM
To: r-help at r-project.org
Subject: [R] color palettes
Hi,
Is there any way to take one color of each color family from a color palettes
like rainbow? For ex, if there are different blues differentiated by intensity,
hue etc, taking one of them. In this case, when using rainbow(n), then how to
select 1 color of each family, for ex 1 blue, 1 red etc? It doesn't matter
which intensity, hue etc is taken as long as 1 color from each family is taken.
Thanks
Carol
[[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.
On Fri, 8 Aug 2014 06:26:35 AM carol white wrote:> Hi, > Is there any way to take one color of each color family from a color > palettes like rainbow? For ex, if there are different bluesdifferentiated> by intensity, hue etc, taking one of them. In this case, when using > rainbow(n), then how to select 1 color of each family, for ex 1 blue, 1red> etc? It doesn't matter which intensity, hue etc is taken as long as 1color> from each family is taken. > >Hi Carol, Since you have asked a question about a fundamental aspect of graphic representation, I'll try to answer it. Be warned, it will be a rather discursive answer. Whenever we try to communicate information about a number of things, where the information is different for each thing, it is essential to securely link the correct information to each thing. In compact graphic representations such as R plots, this usually resolves to labels of some sort. So we could construct a pie chart of the number of emails sent by each person in the present discourse using the names of the people involved. If we simply label each sector of the resulting plot with the names of the people, it will be reasonably informative in displaying each person's contribution. If we venture beyond the comfortable pale of the R help list and try to do this with something like Twitter, where I understand there may be thousands or even millions of contributors on a subject, the pie chart blurs into a chromatic dazzle with an unintelligible fringe of names. We might try to rescue the situation by aggregating the tweets into a few categories such as helpful, sarcastic and noise, but this does not solve the problem of how to display the comparative contributions of the twits involved. So one answer to your question of "How can I intelligibly label hundreds of things with colors?" may be "You can't unless your audience is made up of spectrographs." Plots that attempt to display information about too many things using line types, symbol types and colors often simply confuse the audience. My feeling is that it is the responsibility of the person choosing the method of communication to make sure that it communicates well. So if we want to display something meaningful about the hypothetical pandemonium of tweets above, we might choose to display the categories (helpful, sarcastic and noise) broken down by the sex of the twits. Perhaps in your case you might want to break down the functional category of the genes you are examining by the up- or down-regulation of those genes in different cell types. Your question touches things like "How many letters should there be in the alphabet?" and "How many acronyms for psychological tests can be meaningfully used in a paragraph?" At any rate, I thank you for giving me an idea about graphic illustration. Jim