Mercator's Dying Wish - MapJam

No. It wasn't a better sextant. 

It's the ability to tweak any kind of map to your needs. Draw zones, paths, etc. And then share that easily. Those moments drawing arrows with chalk on the sidewalks of your neighbourhood to get your friends to your birthday party? Over. Sure you can somehow manage something with Google Maps, but this is very well done. Better done. And the sharing part is really smooth. 

Ok ok, you can also draw arrows on the floor. Because it's fun.