This is a great article by AdventureAlan'sUltralightBackpacking, whose thoughts mirror my own on how to use the iPhone for Backcountry Navigation. Click this link to jump to the article.
|The new iPhone 6 and 6+ (pictured) have larger and better displays for map use in the field and significantly better battery life. Changes to Airplane Mode introduced in IOS 8.3 make it easier to manage battery life. We are eaisly getting 6-7 days or more of normal backcountry use without recharging. Photo from adventurealan.com