[amsat-bb] Smartphone (compass) apps which show true north?

[Philip Jenkins]

I'd rather not wade through the process of downloading and installing  the
various multitudes of compass apps to see which of them can indicate true
north (handy for doing satellite demos when you're not at home, and don't
know or don't have the magnetic declination of that location).

My phone doesn't seem to have a magnetometer anyway (from the error
messages I'm getting when I've tried a few compass apps).

Do any of these apps use GPS to show true north, and not just magnetic
north (or both)?

Philip N4HF

P.S. I have an Android phone and tablet, but I'm sure iPhone users could
find this info useful as well.