Suppose for a moment, I have a 13.5 million-point data file that I want to plot as a scatter-plot. gnuplot will happily produce a plot for me, although it takes a little while, and I need a fair bit of RAM.

The resulting .ps file is 212M, however, and makes evince thrash for absolutely ages before displaying it. Converting it to PDF just makes matters worse (up to 275M). I want to be able to include this figure in a pdfLaTeX document.

Annoyingly, runes of the form time gs -r600 -sDEVICE=pdfwrite -sOutputFile=foo-600.pdf -dNOPAUSE -dSAFER -dBATCH foo.ps actually make matters worse - the resulting PDF is even bigger!

Surely there must be an easy way to simplify ps or PDF files? presumably I could force gs to rasterize by outputting to PNG and then converting back to PDF (how?), but that seems a deeply ugly hack...