Thanks for the feedback Nick!

I have to admit that although I've been very proficient at land orienteering most of my life, many of the equations and subtleties I did not understand. As far as variations, I've always been able to calculate that into things using my (to this day) WWII field compass and my topo maps, but doing the math to apply the variations in a digital playground have been very interesting, and I have learned a boatload of new ways to comprehend things.

The project this is all for is coming along nicely. I have put on the CPAN some GPS-related code already, I'll be uploading this once a name is decided (in fact, I added a series of checks/bounds and tests today, so I'm ready to go) by the original author of the code. If they don't respond by Monday morning, I'll have to choose one. Once I'm done with the Arduino stuff and get this little project packaged, I'm going to port it ALL back to Perl to mix in with my Raspberry Pi work. Although the Pi isn't as field-friendly as an Arduino Trinket, there may still be some use for all of it bundled in a specific grouping of modules, but even if not, everything I've learned started as Perl, and the people in the Perl community, so it's the right thing to do.

I like your suggestion of Geo::Compass::Variation. It totally fits the bill for the two simple functions the software provides without leaning directly at one of them, and I personally prefer to have only one capital letter in each section of a namespace if possible... it keeps it clean and unambiguous.

update 2004 hrs EST: Being a land person most of my life and being able to use that knowledge to get from one place in water to the next land area is something I can do in a small scale, I presume that if all the code I'm writing that I'll port back works accurately (Google Compass has been as handy as my physical layout of maps/compass on my living room floor to assume accuracy), I would imagine on a boat/ship with electrical, a Pi, running Perl code could be useful in such situations. It doesn't need to be field light and portable if it's being used in a case that you're not considering weight and size because you're not on foot...