in reply to Speeding up point-in-polygon

One final consideration: is Perl the best choice for implementation environment for this task? A repeated tight loop through a mathematically bound calculation just calls out for a compiled program of some kind. I'll admit, I'm no expert on Perl performance, but sometimes tasks that are 'fast enough' turn out to not be fast enough when you do them 1 trillion times, and it's worth taking the extra effort to write it in a more specialized language.