Fenix 6X Pro, now an elevation data issue!

I have the best results doing that (or, actually using the "auto-calibrate only at start of activity" setting). I find that the elevation profile of the recorded activity has been the smoothest and most accurate using that function. It's actually worked so well for me that I'm downright impressed with its accuracy. I went on a 3-day mountaineering trip last weekend, and the overall elevation gain/loss was accurate to within 1% (compared to what online mapping said it should be), and the highest elevation (recorded on day 2) was only off by like 20 feet.

I find that continuous calibration during activity ends up with poorer results. And "no calibration" usually works fine for recording the overall elevation profile, but as OP learned, it can result in the whole elevation profile being shifted up or down.

Yeah. It seems a little counter intuitive about the continuous calibration thing, but I agree. As I said earlier, seeing a <20m discrepancy for a nearly 3000m climb impressed me. I don't doubt for a minute some people are having issues here, but I think perhaps the plethora of options here sometimes means it becomes harder, not easier to get it right for your particular needs

Good points! Im already using DEM and calibration at start and the elevstion profile looks about right. But, I have used "continiuos" before and I do not know when I changed the setting.

One question is still unanswered, how can we validate the elevation changes of a known corse?

Personally ... I'm not 100 sure. I tend to create a track in PAR, then import it to various places (and basecamp) and look at the differences. What I'm looking for is some reasonably consistency between them. If they're using different DEM's, there will be some changes, and data smoothing does as well.

Short of personally surveying, it seems we just have to accept that there will be some wiggle. 

But I find Garmin Basecamp, being a local app rather than a website, is good for studying elevation profiles of courses, which I tend to do anyway for the hillier runs - together with ClimbPro - to prepare myself for the pain!

Have you installed Basecamp? As it can use your watch's own maps, then you may get a better degree of consistency - that is, once you get the calibration method that works for you, of course.

One thought AndersB.

If you're feeling fit ( :) ) do the same course twice. Both calibrating at start. But first, Calibrate by DEM as the option. Then Calibrate by GPS. I SUSPECT DEM will be most accurate. (but note, SUSPECT) - it should