The Power+ app from RevoRace can receive indoor cycling power meter data from 3rd party devices, convert that data to speed and distance over on preset OR USER-UPLOADED courses, and then create a corresponding GPX file to document performance. Power+ can convert heart rate-to-power for days when a power meter is not available. Power+ can even be used offline with NO SUBSCRIPTION REQUIRED. Great for indoor rowing too!
With Family Sharing set up, up to six family members can use this app.