Strava Elevation Discrepancy

[bloaker]

Yesterday I went to ride Yabitsu as well as take some pictures and look around a bit.
I took two buddies with me that have never been and we had a great ride.
This morning, I looked on strava and was very surprised at the varying elevations of our ride.

The top graph is from my Edge 800.
The second is from an Edge 810.
The third is from a Forerunner 205.

I see my profile is the most smooth and IMO the most accurate.
But what is causing this kind of discrepancy. There is 1100 meters difference on the same ride!

 

[bloaker]

I just looked at an older Strava route I have done of Yabitsu and my elevation is more in line with the other two guys.
I suppose it is a setup thing?

 

[bloaker]

Strava has an option to "Correct Elevation" so I did.
Now the elevation jumped from 1,188 to 2,304.
I think the real number might be somewhere in between.

 

[JackTheCommuter]

The 810 one looks like barometric based... Not too much jitter. The other looks like maybe GPS based with all the jitter. Maybe a configuration like you speculated where the GPS altitude data can be ignored.

Maybe looking at the users historical data will reveal what's normal for the devices.

 

[GrantT]

I've read that Strava takes altitude measurements made using a barometer (like on some Garmin devices) as is, but ignores altitude measurements made by devices without a barometer (like an iPhone or GPS logger) and calculates elevation itself. Elevation according to Strava always comes out at about twice that when using a barometer.

 

[joewein]

I've read that Strava takes altitude measurements made using a barometer (like on some Garmin devices) as is, but ignores altitude measurements made by devices without a barometer (like an iPhone or GPS logger) and calculates elevation itself.

You are correct. See here.