[R] how to fill between 2 stair plots

[Peter Dalgaard]

Williams Scott wrote:
> Hi all,
>
> I want to create a simple plot with 2 type='s' lines on it:
>
> plot(a, b, type='s')
> lines(x, y, type='s') 
>
> I wish to then fill the area between the curves with a colour to
> accentuate the differences eg col=gray(0.95). I cant seem to come up
> with a simple method for this. Any pointers in the right direction much
> appreciated.
>
>   
I don't think there is a really simple method for this. I'd start with
converting the two 's' lines to ordinary lines along the lines of

N <- length(a)
a1 <- c(a[1],rep(a[-1],each=2),a[N]) # possibly a[N]+a_bit for the final
step)
b1 <- rep(b,each=2)

x1, y1 similarly, then

polygon(c(a1,rev(x1)),c(b1,rev(y1), col="grey")

(Did I confuse 's' and 'S'? Anyways, you get the idea)

> Cheers
>
> Scott
> _____________________________
>
> Dr. Scott Williams
>
> MBBS BScMed FRANZCR
>
> Peter MacCallum Cancer Centre
>
> Melbourne, Australia
>
> scott.williams at petermac.org
>
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>   


-- 
   O__  ---- Peter Dalgaard             Øster Farimagsgade 5, Entr.B
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