Histograms with bin proportions on the y-axis

To open a graphics device, you usually use a function like png() or
eps() then do your plotting then dev.off() to close it when you're
done.

Sounds like you need something like hist(x, breaks = 100, freq = TRUE)

Hope that helps,

Michael

On Sun, May 20, 2012 at 3:07 PM, Nick Gayeski

I have what is probably a simple problem. I have a data file from an MCMC
Bayes estimation problem that is a vector of 500,000 numeric values (just
one variable) ranging from 100,000 to 700,000. I need to display the
histogram of this data in a high quality graphic for a figure in a journal
publication. I want 100 bins so as to display a reasonable complete and
smooth histogram, and I need the Y-axis to display the bin proportions.

I'm new to all of the graphics capabilities of R.

Can anyone provide me with the command I need to issue to the call to hist
to get the output that I desire?

?I assume that once I have the desired histogram I will be able to save it
in a format like .eps that will permit it to be reproduced in high
resolution. But any suggestions for this task would also be appreciated.

Regards,

Nick

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See in-line below.

I have what is probably a simple problem. I have a data file
from an MCMC Bayes estimation problem that is a vector of 500,000
numeric values (just one variable) ranging from 100,000 to 700,000.
I need to display the histogram of this data in a high quality
graphic for a figure in a journal publication. I want 100 bins
so as to display a reasonable complete and smooth histogram,
and I need the Y-axis to display the bin proportions.

I'm new to all of the graphics capabilities of R.

Can anyone provide me with the command I need to issue to the call
to hist to get the output that I desire?

The following illustrates how to "customise" the behaviour of
hist() to achieve a desired effect (such as the one you want):

  N <- 500000   ## sample size
  Y <- rnorm(N,mean=400000,sd=100000)  ## the sample
  ## Now make a non-plotted object which contains the histogram info:
  H0 <- hist(Y,breaks=100,plot=FALSE)  ## the bin values are counts
  C <- H0$counts ## extract the counts
  ## Now convert these to proportions (percent or fraction as you wish):
  P <- 100*C/N  ## or P <- C/N for fractional proportions
  ## Now copy the histigram object H0 to H1 and modify H1:
  H1 <- H0 ; H1$counts <- P  ## replaces the "counts" by the proportions
  ## Now plot it:
  plot(H1,ylab="% proportions in bins")

I assume that once I have the desired histogram I will be able to
save it in a format like .eps that will permit it to be reproduced
in high resolution. But any suggestions for this task would also
be appreciated.

Regards,
Nick

As Michael Weylandt has suggested, you can encapsulate the final
plot() command between the opening of a graphics device and the
closure of the device. So if you want an EPS file you can use the
postscript device:

  postscript("myhistoplot.eps",horizontal=FALSE)
  plot(H1,ylab="% proportions in bins")
  dev.off()

and the result will be an EPS file "myhistoplot.eps". You will
probably want to at least vary the aspect ratio (height:width)
and maybe some other things, so give the command

  ?postscript

to find out what the various (and many .. ) options are.

Hoping this helps to get you started!
Ted.

-------------------------------------------------
E-Mail: (Ted Harding) <Ted.Harding at wlandres.net>
Date: 20-May-2012  Time: 22:27:13
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