# Re: [R] color ranges on a 2D plot

From: Greg Snow <Greg.Snow_at_imail.org>
Date: Wed, 16 Jan 2008 14:12:52 -0700

You did not say what variable you want to be in the ranges to determine the colors, but try any of these to see if they do what you want:

> x <- runif(100)
> y <- runif(100)
> z <- runif(100)
> plot(x,y, pch=16, col=ifelse( x < 0.5, 'blue','red'))
> plot(x,y, pch=16, col=ifelse( y < 0.5, 'blue','red'))
> plot(x,y, pch=16, col=ifelse( z < 0.5, 'blue','red'))
>
> library(TeachingDemos)
> y[1] <- 0.5
> plot(x,y, pch=16, col='red,)
> clipplot( points(x,y,pch=16,col='blue'), ylim=c(0,0.5) )

The last one is probably overkill, but can give a nice effect with larger cex values.

If none of those work for you, restate the question with better detail.

Hope this helps,

```--
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 dxc13
> Sent: Wednesday, January 16, 2008 1:35 PM
> To: r-help_at_r-project.org
> Subject: [R] color ranges on a 2D plot
>
>
> useR's
>
> I am trying to color the points on a scatter plot (code
> below) with two colors.  Red for values 0.5 -1.0 and blue for
> 0.0 - .49.  Does anyone know a easy way to do this?
>
> x <- runif(100, 0, 1)
> y <- runif(100, 0, 1)
> plot(y ~ x, pch=16)
>
> Thanks,
> dxc13
> --
> View this message in context:
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> 93457.html
> Sent from the R help mailing list archive at Nabble.com.
>
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