Originally Posted by
tenrec
These were tracked with the Samsung Health app in my Android phone, but I've gotten similar inconsistency with other apps (including Strava and Map My Ride) and other phones (including an iPhone.) How do the apps keep track of elevation? Do they use GPS data (which I think would be very accurate) or barometric pressure (probably less accurate)? Has anyone else noticed anything like this?
Phones typically use GPS to determine elevation, while many bike-specific devices (like the Garmin Edge series) use barometric pressure.
GPS is terribly inaccurate at measuring elevation. If you are using a phone to record a ride, that easily explains the wide variation in elevation gain.
Barometric pressure is much more accurate. But errors can creep in there, also. If the pressure rises or falls during a ride, the device will record it as phantom elevation loss or gain.