# Re: [R] How to plot curves with more than 8 colors

From: jim holtman <jholtman_at_gmail.com>
Date: Wed 28 Dec 2005 - 15:28:17 EST

It might be hard to differentiate between each color with having 255 of them. Here is an example of using ColorRampPalette to create a set of colors. You can experiment with as many differing ones as you want to to get the difference that you want:

# use 5 colors to create a sequence (you can add more colors if you want to) f.c <- colorRampPalette(c('red','green','orange','blue','yellow'))(255) plot(0,type='n', ylim=c(0,255), xlim=c(0,1)) for (i in 1:255) segments(0, i, 1, i, col=f.c[i])

On 12/27/05, Vincent Deng <bioflash@gmail.com> wrote:
>
> Hi,
>
> I think maybe I didn't specify color codes properly. That is,the
> difference between each color is not sharp enough for me to identify
> them as different colors.
>
> So can you tell me about how to specify the color properly so that the
> difference among each color can be identified clearly?
>
> Thanks again and again ...
>
> On 12/27/05, Uwe Ligges <ligges@statistik.uni-dortmund.de> wrote:
> > Vincent Deng wrote:
> >
> > > Dear Uwe,
> > >
> > > Sorry, I did not describe my question clearly. I created a matrix to
> > > store color code using rgb function.
> > >
> > > abc = rgb(6:36,0,0,maxColorValue = 255)
> > >
> > > And after running codes like this
> > >
> > > for (i in c(1:20))
> > > {
> > > points(...,...,col=abc[i])
> > > lines(...,col=abc[i])
> > > }
> > >
> > > R still used 8 colors of abc color codes repeatedly to draw the
> diagram
> > >
> > > Any helps?
> >
> >
> > No, it does not (in fact, all appears to be more or less black on my
> > screen ;-)). Another example:
> >
> > plot(1:255, col=rgb(1:255,0,0,maxColorValue = 255))
> >
> > Uwe Ligges
> >
> >
> >
> > > Best Regards...
> > >
> > > On 12/27/05, Uwe Ligges <ligges@statistik.uni-dortmund.de> wrote:
> > >
> > >>Vincent Deng wrote:
> > >>
> > >>>Hi,
> > >>>
> > >>>I'm a new hand in R language. I have about 20 groups of data[x,y] and
> > >>>want to plot them on a graph. To do this, I write a for-loop as
> > >>>following: (some codes are omitted for simplicity)
> > >>>
> > >>>for (i in c(1:20))
> > >>>{
> > >>> points(...,...,col=i)
> > >>> lines(...,col=i)
> > >>>}
> > >>>
> > >>>The problem is "R only plot them with 8 colors repeatly". Could
> anyone
> > >>>help me solve this problem? Or is there any package providing plot
> > >>>function without color limit?
> > >>
> > >>
> > >>After typing
> > >>
> > >> ?colors
> > >>
> > >>I get a nice help page that points me to a lot of other functions that
> > >>generate more than 8 colors. Maybe your installation of R is broken
> and
> > >>you cannot see this help page? You certainly tried to get help on
> colors
> > >>as well.
> > >>
> > >>There is no limit of the color number in the functions above, simply
> > >>specify the color you want to get. The only color limit applies for
> the
> > >>device and for most devices and rgb colors this is 256^3.
> > >>
> > >>Uwe Ligges
> > >>
> > >>
> > >>
> > >>
> > >>
> > >>>Best Regards...
> > >>>
> > >>>______________________________________________
> > >>>R-help@stat.math.ethz.ch mailing list
> > >>>https://stat.ethz.ch/mailman/listinfo/r-help
> http://www.R-project.org/posting-guide.html
> > >>
> > >>
> >
> >
>
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>

```--
Jim Holtman
Cincinnati, OH
+1 513 247 0281

What the problem you are trying to solve?

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