[R] points() colored by value

Sarah Goslee sarah.goslee at gmail.com
Tue Nov 15 20:26:52 CET 2011

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.


> something like that
> But haven't found any solution at the moment.
> Thanks.
> Chris

Sarah Goslee

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