Graphics in Perl
Bill Dillon gave a presentation on Graphics in Perl. Since this talk ranged from graphing metrics for programming QA through light curves for cataclysmic variable stars. (Bill's hobby is astronomy.)
Bill covered the GD::Graph module that supports creating various forms of charts, including line, point, bar and pie charts. Since his work data is proprietary, he began by graphing the number of attendees at the Houston.pm meetings. (Actual numbers may vary.)
After showing how easy it is to chart data like this in multiple styles, Bill went on to give an overview of cataclysmic variable stars and the people who study them. (AAVSO: American Association of Variable Star Observers.)
This background leads to a point chart showing almost 100 years of data on the cataclysmic variable star SS Cygni. In the process, Bill showed how he used Perl and GD::Graph to display a data set that Excel would not open. He also described the need to extend the graph size when dealing with large data sets, as well as the problems with plotting star magnitude data in a reasonable fashion for people to read.
Bill also recommended the books Perl Graphics Programming (Wallace, 2002) and Graphics Programming with Perl (Verbruggen, 2002). He said that neither one had all of the information that he needed, but between them, he could normally figure it out.
- Bill's PowerPoint presentation.
- Example code from Perl Graphics Programming wgd_graph_test.pl
- The program that generated the lightcurve chart: graph_jd_mag.pl
- Lightcurve for the cataclysmic variable star SS Cygni (Warning: this chart is 50,000 pixels wide.)