# [R] Scatter Plot in R - Help

Petr Klasterecky klaster at karlin.mff.cuni.cz
Fri Apr 27 23:15:46 CEST 2007

```If I understand correctly what A. Ezhil asked for, polygons won't help
here. For coloring the individual points check ?points and use subsets, e.g.

plot(x,y)
points(x[x>y-1],y[x>y-1], col="red")

or something similar.
Petr

John Kane napsal(a):
> Here is a recent posting by Petr Klasterecky  that
> does not seem to be on the archive yet that may help.
> ----------------------------------------------
>
> What do you mean by background? Maybe this is enough:
>
> plot(seq(-3,3,.01), dnorm(seq(-3,3,.01)), type="n",
> xlab="x",
> ylab="f(x)", main="Normal density")
> polygon(x=c(-4,0,0,-4), y=c(-1,-1,.5,.5), col="red")
> polygon(x=c(4,0,0,4), y=c(-1,-1,.5,.5), col="blue")
> lines(seq(-3,3,.01), dnorm(seq(-3,3,.01)), type="l",
> lwd=2)
>
> Play a little bit with the polygon margins to get what
> you need. You
> can
> even generate them automatically based on your data.
>
> Petr
> -----------------------------------------------
> --- A Ezhil <ezhil02 at yahoo.com> wrote:
>
>> Dear All,
>>
>> I am using the following commands to do the scatter
>> plot of two vectors, say X and Y.
>>
>> plot(X,Y, col="blue")
>> abline(a=1,b=1, col="red")
>> abline(a=-1,b=1, col="green")
>>
>> I would like to split the scatter plot into 3 part
>> with 3 different colors: (i) points lies between 2
>> lines, (ii) points above line 1, and (iii) points
>> below line 2. I am struggling to do this. I would
>> greatly appreciate any help in doing this.
>>
>>
>> Kind regards,
>> Ezhil
>>
>> ______________________________________________
>> R-help at stat.math.ethz.ch mailing list
>> https://stat.ethz.ch/mailman/listinfo/r-help
>> http://www.R-project.org/posting-guide.html
>> and provide commented, minimal, self-contained,
>> reproducible code.
>>
>
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