The work of the devil, I say.
You dont want to get involved with it, map, pencil, and eyeball is all you need. If it was good enough for my Dad in the RAF to fly all round Europe, it is good enough for me. God gave you eyes for a reason.
Terribly unreliable as well what with batteries running out, GPS signal being switched off and the MOD jamming trials all round the country.
No, you dont wanted to get involved my boy - stick to tried and tested means.
