Altimeter, Garmin Connect, and Strava

Regarding altitude, the VA3M has a barometric sensor, but that is only used to measure delta's and cannot be used to measure absolute elevation since the air pressure is not a constant. It is mainly used for stair counting During activities I think the GPS altitude is recorded. So, I expect that the Venu SQ will use GPS during activities. Cant tell you how good it is, since my country is very flat. 

I sync the VA3M to Strava and I do see that the altitude is synced there. 

gordonwd said:

The Venu Sq (and Sq 2) do not have an altimeter, so they do not record elevation changes during an activity -- correct?

Incorrect. Those device do record GPS-based elevation, which can be very unstable. And this is why ...

gordonwd said:

when your activity is uploaded to Garmin Connect, it uses Garmin's mapping data to generate an elevation profile.

This is correct.

gordonwd said:

does it work reasonably well?

In most cases, it does. However the DEM data are of varying quality depending on geographical region, and do not take into account man-made objects, so for example if you cross a bridge, the corrected elevation will show you  going on the ground (or water) under the bridge.

gordonwd said:

if Connect is configured to send your activities to Strava, does the data sent to Strava include the calculated elevation data?

I'm not sure, but I believe the original uncorrected GPS altitude data is sent to strava.

Thanks, that makes sense. My old Forerunners didn't have altimeters and we all thought that their elevation readings were "good enough" for those times.