R help - Nov 2005 - Superimpose Histograms

Hi all,

I have data which is represented as a histogram and want to add more
data / another histogram to this plot using another color. That is I
need to superimpose multiple histograms.
But have no idea how to do this.

Can anybody please give me a hint?

Thanks,
Andreas

-- 

Andreas Wilm

Institut fuer Physikalische Biologie
Heinrich-Heine-Universitaet Duesseldorf
http://www.biophys.uni-duesseldorf.de

E-Mail: wilm at biophys.uni-duesseldorf.de / 0x7C68FBCC
Phone:  +49 211 8115966

See

library(R.basic)
example(plot.histogram)

  x1 <- rnorm(1000,  0.4, 0.8)
  x2 <- rnorm(1000,  0.0, 1.0)
  x3 <- rnorm(1000, -1.0, 1.0)
  hist(x1, width=0.33, offset=0.00, col="blue", xlim=c(-4,4),
       main="Histogram of x1, x2 & x3",
       xlab="x1 - blue, x2 - red, x3 - green")
  hist(x2, width=0.33, offset=0.33, col="red", add=TRUE)
  hist(x3, width=0.33, offset=0.66, col="green", add=TRUE)

It overloads the default plot.histogram() (called when you do hist()) so 
it takes arguments 'offset' and 'width' too.

You can the package following the instructions at http://www.braju.com/R/.

BTW, I'm sure some would add, so I do it here instead, that it is better 
to plot density curves, cf. ?density.

Cheers

Henrik

Andreas Wilm wrote:
> Hi all,
> 
> I have data which is represented as a histogram and want to add more
> data / another histogram to this plot using another color. That is I
> need to superimpose multiple histograms.
> But have no idea how to do this.
> 
> Can anybody please give me a hint?
> 
> Thanks,
> Andreas
>