I’ve started to use gnuplot, which is a “command-line driven graphing utility.” It’s not open source but it is freely available (under some other license) and it’s been around since 1986. I don’t think it’s going to “go commercial” any time soon…
It’s proving challenging to understand gnuplot and get it to do what I want it to do, but I’ve tried using OpenOffice and Numbers and neither one can seem to plot 24,000+ data points. I considered updating my Perl code to write SVG files (and I may revisit that) but gnuplot seems to be the tool to use in this case…
Hopefully by the time I’ve collected a few more weeks worth of data I’ve got a better idea how to use gnuplot… but if you’ve got any pointers, I’d love to hear them.