Google Maps had been built-in with iOS since the launch of the first iPhone, but the app was dropped when Apple replaced it with their own mapping app in September. Although Apple Maps introduced impressive Flyover graphics and turn-by-turn directions to iOS devices, its navigation data is not up to par with what Google Maps once offered. Apple Maps has produced erroneous directions, placed cities and landmarks in the wrong spot, and still lacks transit directions.
Although Apple Maps users can report incorrect data through the app, Maps hasn’t seen any significant changes since its launch.
A new Google Maps app wouldn’t replace Apple’s native Maps, but it would give iOS users a trustworthy maps app to use while Apple improves its own offering. There's no offical word from Google or Apple at this time, so it's unclear when exactly we'll see the app show up in the App Store.
