R help - Apr 2009 - ColorRamp different from ColorRampPalette

I try to use ColorRamp as ColorRampPalette (i.e. with the same gradient), but
it seems there is a nuance that I've missed.

pal.crp<-colorRampPalette( c("blue", "white",
"red"), space = "rgb")
plot(rep(0,40),pch=16,col=pal.crp(40))
# is great

But, using the same gradient with colorRamp is giving erratic colors.

pal.cr<-colorRamp( c("blue", "white", "red"),
space = "rgb")
plot(rep(0,40),pch=16,col=pal.cr((0:40)/40))
# is not great
>From the help : "colorRamp returns a function that maps values between
0 and
1 to colors" ...colors I guess taken from the gradient, but I don't get
the
gradient.

Etienne

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Look at the output of pal.cr((0:40)/40)
Hadley

On Fri, Apr 17, 2009 at 2:42 PM, Etienne B. Racine <etiennebr at
gmail.com> wrote:
>
> I try to use ColorRamp as ColorRampPalette (i.e. with the same gradient),
but
> it seems there is a nuance that I've missed.
>
> pal.crp<-colorRampPalette( c("blue", "white",
"red"), space = "rgb")
> plot(rep(0,40),pch=16,col=pal.crp(40))
> # is great
>
> But, using the same gradient with colorRamp is giving erratic colors.
>
> pal.cr<-colorRamp( c("blue", "white",
"red"), space = "rgb")
> plot(rep(0,40),pch=16,col=pal.cr((0:40)/40))
> # is not great
>
> >From the help : "colorRamp returns a function that maps values
between 0 and
> 1 to colors" ...colors I guess taken from the gradient, but I
don't get the
> gradient.
>
> Etienne
>
> --
> View this message in context:
http://www.nabble.com/ColorRamp-different-from-ColorRampPalette-tp23104641p23104641.html
> Sent from the R help mailing list archive at Nabble.com.
>
> ______________________________________________
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> PLEASE do read the posting guide
http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.
>


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