[R] color ranges on a 2D plot

Greg Snow Greg.Snow at imail.org
Wed Jan 16 22:12:52 CET 2008


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: 
> http://www.nabble.com/color-ranges-on-a-2D-plot-tp14893457p148
> 93457.html
> Sent from the R help mailing list archive at Nabble.com.
> 
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