Magellan couldn't have circumnavigated the Earth without it. We're sure, we checked.
[1500s. Ferdinand Magellan stands on the bow of his ship, looking out across the Atlantic Ocean.]
Oh hello. I saw you there but didn't want to say anything for a while.
Sometimes when I go exploring, I get lost. Yes, even one of the world's most famous explorers - which I'm sure to become following my current journey - can sometimes lose track of where my boat be at. Luckily, I use the GPS with my own namesake to keep me on track this time. For example, right now we're getting ready to round the tip of South America, according to my GPS, with enough room to avoid falling of the edge of Earth's plate. Whew!
I wonder why they call it South America.
Anyway, from here on out, I won't get lost ever again. And with a battery life of--uh oh. Has it been two hours already? Hmm, and a replacement battery won't be ready for a couple of centuries. Probably. Well, it was fun while it lasted.
It's probably best if you use this for roads anyway. There aren't any in the ocean. So I hear.