There are a couple of apps like that, although I don't know if they are for the iPhone; go to your App Store. Otherwise, if you have any DAW software, you can create that very map in something like Logic or even Garage Band or the other free sequencing programs available.
Lester Devoe Flamenco Negra
Lester Devoe Flamenco Blanca
Aparicio Flamenco Blanca with RMC pickup
Bartolex 7-string with RMC pickup
Giannini 7-string with Shadow pickup
Sal Pace 7-string archtop