Re: iPad GPS accuracy?
I have a IPAD2 wifi. It does NOT have GPS. It uses cell towers for locale. This is very accurate if you are lake or potentially very close coastal. I've used it 2+ miles off shore.
However, if there isn't a strong enough signal or you are in a dead zone, then it barely works for location based services.
The Dual or Bad Elf or Bad Elf Pro solve this. Google them. They range from 65-180 bucks.
I'm not sure if the newer IPADS have GPS chips or not in the WIFI only units. A quick (lol) check of the apple web site would verify this or not.
Happy Sailing... :-)