# [R] overlay shaded area in base r plot

ani jaya g@@@uu| @end|ng |rom gm@||@com
Tue Sep 19 11:21:07 CEST 2023

```Thank you very much for the solution. Absolutely will try this to see which
one produces better plot.

On Tue, Sep 19, 2023, 18:17 Jan van der Laan <rhelp using eoos.dds.nl> wrote:

> Shorter/simpler alternative for adding a alpha channel
>
>
>
> So I would use something like:
>
>
> # Open new plot; make sure limits are ok; but don't plot
> plot(0, 0, xlim=c(1,20),
>    ylim = range(c(mean1+sd1, mean2+sd2, mean1-sd1, mean2-sd2)),
>    type="n", las=1,
>    xlab="Data",
>    ylab=expression(bold("Val")),
>    cex.axis=1.2,font=2,
>    cex.lab=1.2)
> polygon(c(1:20,20:1),
>    c(mean1[1:20]+sd1[1:20],mean1[20:1]-sd1[20:1]),
>    border = NA)
> polygon(c(1:20,20:1),
>    c(mean2[1:20]+sd2[1:20],mean2[20:1]-sd2[20:1]),
>    border = NA)
> lines(1:20, mean1,lty=1,lwd=2,col="blue")
> lines(1:20, mean2,lty=1,lwd=2,col="yellow")
>
>
> On 19-09-2023 09:16, Ivan Krylov wrote:
> > В Tue, 19 Sep 2023 13:21:08 +0900
> > ani jaya <gaaauul using gmail.com> пишет:
> >
> >>
> polygon(c(1:20,20:1),c(mean1[1:20]+sd1[1:20],mean1[20:1]),col="lightblue")
> >>
> polygon(c(1:20,20:1),c(mean1[1:20]-sd1[1:20],mean1[20:1]),col="lightblue")
> >>
> polygon(c(1:20,20:1),c(mean2[1:20]+sd2[1:20],mean2[20:1]),col="lightyellow")
> >>
> polygon(c(1:20,20:1),c(mean2[1:20]-sd2[1:20],mean2[20:1]),col="lightyellow")
> >
> > If you want the areas to overlap, try using a transparent colour. For
> > example, "lightblue" is rgb(t(col2rgb("lightblue")), max = 255) →
> > "#ADD8E6", so try setting the alpha (opacity) channel to something less
> > than FF, e.g., "#ADD8E688".
> >
> > You can also use rgb(t(col2rgb("lightblue")), alpha = 128, max = 255)
> > to generate hexadecimal colour strings for a given colour name and
> > opacity value.
> >
>
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