Thinning Lattice Plot

-----Original Message-----
From: r-help-bounces at r-project.org [mailto:r-help-bounces at r-
project.org] On Behalf Of David Winsemius
Sent: Monday, July 30, 2012 5:47 PM
To: Elliot Joel Bernstein
Cc: r-help at r-project.org
Subject: Re: [R] Thinning Lattice Plot


On Jul 30, 2012, at 2:13 PM, Elliot Joel Bernstein wrote:

Is there an easy way to "thin" a lattice plot? I often create plots
from
large data sets, and use the "pdf" command to save them to a file,
but the
resulting files can be huge, because every point in the underlying
dataset
is rendered in the plot, even though it isn't possible to see that
much
detail.

For example:

require(Hmisc)
x <- rnorm(1e6)

pdf("test.pdf")
Ecdf(x)
dev.off()

The resulting pdf files is 31MB. Is there any easy way to get a
smaller pdf
file without having to manually prune the dataset?

There are plotting routines that display the density of distributions.
I use hexbin fairly frequently but that is for 2d plots.  If you
wanted the ECDF of a 1d vector, you could use cumsum() on the output
of hist() or quantile() with suitable arguments to their parameters to
control the degree of aggregation. Either of these yields an 8KB file
on my machine.

 > pdf("test.pdf")
 > xyplot( cumsum(hist(x, plot=F)$intensities) ~ hist(x, plot=F)

$breaks )

 > dev.off()

quartz
      2

 > pdf("test.pdf")
 > xyplot( (0:100)/100 ~ quantile(x, prob=(0:100)/100)  )
 > dev.off()

quartz
      2

Thanks.

- Elliot

--
Elliot Joel Bernstein, Ph.D. | Research Associate | FDO Partners, LLC
134 Mount Auburn Street | Cambridge, MA | 02138
Phone: (617) 503-4619 | Email: elliot.bernstein at fdopartners.com

David Winsemius, MD
Alameda, CA, USA