[R] Multiple plot jpeg file

[Marc Schwartz]

On Tue, 2007-06-19 at 15:39 -0400, Bill Hunsicker wrote:
> R-Help,
> 
> I am executing a R script and would like to put multiple plots into a
> single file. For some reason the contents of plotfile.jpg always seem to
> contain the last plot and not all plots.
> 
> If I do same thing with pdf, a multiple plot file is created.
> 
> Can you help me?
> 
> Regards,
> Bill

There is no notion of a 'page' in bitmapped devices as there is with PDF
or PS devices. Thus, each time you call plot(...) with a bitmapped
device, the previous output is lost.

If you want multiple plots in a bitmapped device, you would need to use
layout() or par(mfrow/mfcol) to define multiple plot regions within the
overall bitmapped output.

For example:

jpeg("test.jpg", 400, 400)

# Set for 2 rows, 1 col
par(mfrow = c(2, 1))

# Set the margins to make room
par(mar = c(1, 4, 4, 2))

# Draw a barplot
barplot(1:5)

# Set the margins to make room
par(mar = c(5, 4, 1, 2))

# Do a scatterplot
plot(1:10)

# Close the device
dev.off()


Adjust other pars as required.

See ?par and ?layout

HTH,

Marc Schwartz