R help - Nov 2011 - points() colored by value

Hi R users,

I want to colored points by their value

for example:

x <- c(1,2,3,4)
y <- c(1,2,3,4)
z <- c(2,3,4,9)

y and x are coordinates

z is the value of the coordinates

points(x,y,col= rainbow(z))

something like that

But haven't found any solution at the moment.

Thanks.

Chris



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Try either col=z or col=rainbow(max(z))[z] depending on what color scheme you
want.

Michael 

On Nov 15, 2011, at 1:47 PM, Chris82 <rubenbauar at gmx.de> wrote:
> Hi R users,
> 
> I want to colored points by their value
> 
> for example:
> 
> x <- c(1,2,3,4)
> y <- c(1,2,3,4)
> z <- c(2,3,4,9)
> 
> y and x are coordinates
> 
> z is the value of the coordinates
> 
> points(x,y,col= rainbow(z))
> 
> something like that
> 
> But haven't found any solution at the moment.
> 
> Thanks.
> 
> Chris
> 
> 
> 
> --
> View this message in context:
http://r.789695.n4.nabble.com/points-colored-by-value-tp4073640p4073640.html
> Sent from the R help mailing list archive at Nabble.com.
> 
> ______________________________________________
> R-help at r-project.org mailing list
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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.

Hi Chris,

On Tue, Nov 15, 2011 at 1:47 PM, Chris82 <rubenbauar at gmx.de>
wrote:
> Hi R users,
>
> I want to colored points by their value
>
> for example:
>
> x <- c(1,2,3,4)
> y <- c(1,2,3,4)
> z <- c(2,3,4,9)
>
> y and x are coordinates
>
> z is the value of the coordinates
>
> points(x,y,col= rainbow(z))
In the general sense:
plot(x, y, col=rainbow(length(unique(z)))[as.factor(z)])

converting z to a factor to use as an index is just a quick way to
convert z to sequential values 1,2,3,4 rather than 2,3,4,9 and to
ensure that multiple and unsorted values use the correct color. If z
contains only sequential values, that bit is unnecessary.

I like RColorBrewer for things like this, rather than rainbow, but it
depends on what you're trying to do.

Sarah
> something like that
>
> But haven't found any solution at the moment.
>
> Thanks.
>
> Chris
>
>
-- 
Sarah Goslee
http://www.functionaldiversity.org