Hi, how can I create a rainbow gradient in R? For example, let's say I have
a plot of y = x...and I want the plot to go from red -> orange -> yellow
->
green -> blue -> etc.
Right now, I know how to do something like go from red to blue, using the
plotrix library:
library(plotrix)
redToBlue <-
color.scale(x,redrange=c(0,1),greenrange=c(0,1),bluerange=c(0,1),extremes=c("red","blue"))
plot(x, y, col=redToBlue)
But I can't figure out how to make the colors a rainbow. (I don't
understand
how the redrange, greenrange, and bluerange parameters in color.scale work.)
Could someone please help?
Thanks!
[[alternative HTML version deleted]]
plot(1:20, col=rainbow(20)) On Wed, Sep 17, 2008 at 4:58 PM, Gillian Silver <haettulegur at gmail.com> wrote:> Hi, how can I create a rainbow gradient in R? For example, let's say I have > a plot of y = x...and I want the plot to go from red -> orange -> yellow -> > green -> blue -> etc. > Right now, I know how to do something like go from red to blue, using the > plotrix library: > > library(plotrix) > redToBlue <- > color.scale(x,redrange=c(0,1),greenrange=c(0,1),bluerange=c(0,1),extremes=c("red","blue")) > plot(x, y, col=redToBlue) > > But I can't figure out how to make the colors a rainbow. (I don't understand > how the redrange, greenrange, and bluerange parameters in color.scale work.) > > Could someone please help? > > Thanks! > > [[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. >-- Stephen Sefick Research Scientist Southeastern Natural Sciences Academy Let's not spend our time and resources thinking about things that are so little or so large that all they really do for us is puff us up and make us feel like gods. We are mammals, and have not exhausted the annoying little problems of being mammals. -K. Mullis
Dear Gillian, See ?rainbow and its example. HTH, Jorge On Wed, Sep 17, 2008 at 4:58 PM, Gillian Silver <haettulegur@gmail.com>wrote:> Hi, how can I create a rainbow gradient in R? For example, let's say I have > a plot of y = x...and I want the plot to go from red -> orange -> yellow -> > green -> blue -> etc. > Right now, I know how to do something like go from red to blue, using the > plotrix library: > > library(plotrix) > redToBlue <- > > color.scale(x,redrange=c(0,1),greenrange=c(0,1),bluerange=c(0,1),extremes=c("red","blue")) > plot(x, y, col=redToBlue) > > But I can't figure out how to make the colors a rainbow. (I don't > understand > how the redrange, greenrange, and bluerange parameters in color.scale > work.) > > Could someone please help? > > Thanks! > > [[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. >[[alternative HTML version deleted]]
On Wed, Sep 17, 2008 at 3:58 PM, Gillian Silver <haettulegur at gmail.com> wrote:> Hi, how can I create a rainbow gradient in R? For example, let's say I have > a plot of y = x...and I want the plot to go from red -> orange -> yellow -> > green -> blue -> etc.Why would you want to? See http://epub.wu-wien.ac.at/dyn/openURL?id=oai:epub.wu-wien.ac.at:epub-wu-01_c87 for some better alternatives. Hadley -- http://had.co.nz/
On 17/09/2008 4:58 PM, Gillian Silver wrote:> Hi, how can I create a rainbow gradient in R? For example, let's say I have > a plot of y = x...and I want the plot to go from red -> orange -> yellow -> > green -> blue -> etc. > Right now, I know how to do something like go from red to blue, using the > plotrix library: > > library(plotrix) > redToBlue <- > color.scale(x,redrange=c(0,1),greenrange=c(0,1),bluerange=c(0,1),extremes=c("red","blue")) > plot(x, y, col=redToBlue) > > But I can't figure out how to make the colors a rainbow. (I don't understand > how the redrange, greenrange, and bluerange parameters in color.scale work.) > > Could someone please help?Others have pointed you to the rainbow() function; you should also look at colorRamp, in case you want to construct your own colour sequence. Duncan Murdoch
Gillian Silver wrote:> Hi, how can I create a rainbow gradient in R? For example, let's say I have > a plot of y = x...and I want the plot to go from red -> orange -> yellow -> > green -> blue -> etc. > Right now, I know how to do something like go from red to blue, using the > plotrix library: > > library(plotrix) > redToBlue <- > color.scale(x,redrange=c(0,1),greenrange=c(0,1),bluerange=c(0,1),extremes=c("red","blue")) > plot(x, y, col=redToBlue) > > But I can't figure out how to make the colors a rainbow. (I don't understand > how the redrange, greenrange, and bluerange parameters in color.scale work.) >Hi Gillian, Try: my.rainbow<-color.scale(x,c(1,1,0,0),c(0,1,1,0),c(0,0,0,1)) The "extremes" argument takes precedence over your color ranges Jim
quote: From: Gillian Silver <haettulegur_at_gmail.com> Date: Wed, 17 Sep 2008 14:11:39 -0700 What would I do if I have something like: x <- rnorm(1:1000) y <- rnorm(1:1000) z <- x + y and I want the rainbow to increase with z? (i.e., red for lowest z...all the way up to the last color in the rainbow for the highest z) ----------- I can't help w/ a 3-d function directly, but my cute little tool clplot() will do exactly that for any pair of x, y vectors. It's available in the latest plotrix package. The code is not very complicated, so I'd imagine you could rewrite it to handle z= f(x,y) on your own :-) Carl