
The iPhone maps cover all of the USA and Canada. In local terms they are a combo of the "Great Lakes" Gold chip (Ottawa River, Rideau River, St Larry, etc) and the HotMaps chip. This means that in addition to the excellent maps for the navigable waterways such as the Ottawa and Rideau, there are good maps of the major lakes in the area (Mississippi, White, Calabogie, Kamaniskeg to name a few). A neat feature is the ability to overlay a Google map so you see both the lake/river map and the actual terrain.
I have a Lowrance H2Oc handheld and a Navionics chip and after poking about for a few hours with the maps on both devices, I've come to the conclusion that there's not much need for the handheld anymore for boating and fishing purposes. The handheld and a topo chip will probably now just find a permanent home on the ATV.
That's my .02. You're mileage may vary.
Hope you found this useful.....
Doug