Elevation gain, loss and plot are wrong in Garmin Connect

In my experience, any GPX that is imported into Garmin Connect has the elevation data replaced with DEM elevation data.

What Garmin device are you using?

If you want to preserve the elevation data in the GPX file, copy the file directly to your Garmin device and avoid going via Garmin Connect.

Thanks for your reply. I have fenix 6X. Yes, they replace the elevation data with DEM elevation and it used to be very similar but it's only recently that it got bad. Maybe they opted for a cheaper data set for my region. I'll try importing directly to my watch.

I think Garmin use the same DEM data that nearly everyone else uses, the NASA SRTM data set. It may be they have made some smoothing algorithm changes recently.

Can you post the source GPX file and the web site you downloaded it from?

Is this an out-and-back course?

Thanks for the link. I couldn't see how to download the GPX file but looking at the map of the route, there appear to be very few track points between Dent de Fenestral and Col de Fenestral as marked yellow arrows on the image below.

If the track points there are all have a similar altitude, this may be causing Garmin Connect to think that part of the route is level.

Ah cool, I'll try adding more points next time. I couldn't attach a gpx, but I have changed the type from gpx to txt.  Here is the GPXdentdefenestral.txt

Thanks, that worked!

As you can see in the image below, there are only seven track points, #518 - #524, covering the section I highlighted earlier. The white circle is at point #518. (Leg length is the distance from the previous point.)