Too smoothed elevation profile

Hi everyone,

For a few weeks now I noticed that the elevation data are really smoothed a lot and that because of this it doesn't catch any ascent/descent smaller than 30m.

2 days ago I kept looking at my Instinct during such a little ascent and the elevation continued decreasing (around -15m) instead of increasing (around +17m).
You can see this between 52' and 55' of the data. I put the original data (whith barometric altimeter) and the data with elevation correction of GC. On the overall the global ascent with the Instinct is 365m intead of 461m !

Has anyone observed the same ? I would say it is since 3.10 software (but not completely sure).

I saw on the forum that FR935 and Fenix 5 already had the same kind of bug that has been fixed afterwards but it would be strange from Garmin that now they introduce this same bug in the Instinct...

I also have some glitches (eg between 26' and 28') but this is not new and the glitch is filtered so that it is not included in the total ascent/descent.
ciq.forums.garmin.com/.../1474147.png ciq.forums.garmin.com/.../1474148.png

0 tafuk2 over 6 years ago

I have mentioned this on these forums a few times but I think we are in the minority on here as others don't seem to be having the same issue.

I use the elevation correction feature on Garmin connect for every activity I record on the Instinct and I estimate it has on average a difference of ~400ft per 1000ft between the corrected elevation and what is recorded on the instinct because of the smoothing.

For me this has not been any different for any firmware version, but hoping it can be fixed.

I do not use the elevation correction option for activities recorded on a Fenix.

0 Rick11 over 6 years ago

My average ascent / descent during a typical run is about 300mt. Since I start and I arrive in the same place, the ascent and descent should be exactly equal but they never are. The difference is not big, about 10-20mt at most and it seems independent from the total ascent (whether you do 100mt or 600mt, you always end up with the same difference between ascent and descent).

In my case, 15mt on 300mt is about 5%, a perfectly acceptable error.

I don't think this issue can be corrected. It depends from changes in the ambient pressure. In a few hours, the ambient pressure may change slightly and it's very difficult for our Instinct to distinguish between pressure changes due to change in elevation and pressure changes due to changes in the weather, since the sensor is the same. Suunto has Fused-Alti, but also using GPS data has some problems.

0 tafuk2 over 6 years ago

I cannot see why it cannot be fixed as it was not an issue with the Fenix. Perhaps having the option to switch to GPS elevation.

Yesterdays activity:

https://connect.garmin.com/modern/activity/3584129995

434m elev gain, 543m corrected

Previous day:

https://connect.garmin.com/modern/activity/3579519247

462m elev gain, 589m corrected

0 dav.dc over 6 years ago

Ok, now I think this not a software issue.

A few days ago I had a good elevation profile during a run. Here is what I tried : I updated to 3.52 (but I don't think it changed anything), I put my Instinct a bit in warm water before, and I wore it on my right wrist.
Today I wore it on my left wrist again and it was ok at the beginning but at the end it is smoothed a lot again.

I found a thread talking about cleaning for the vivoactive 3:

https://forums.garmin.com/forum/into-sports/health-fitness/vivoactive-3-aa/1348358-clean-altimeter-holes

So my feeling is that the issue is mainly due to sweat entering the barometer hole, and with accumulation of salt this might create some kind of a buffer smoothing the pressure measured by the sensor.
And wearing the watch on the right wrist might reduce sweat accumulation caused by folding my wrists back.

After thinking about all this, it is possible that I have this issue since I started taking off my Instinct when having a shower. This helped me to avoid moisture under it causing skin irritation, but then I stopped cleaning it...

0 tafuk2 over 6 years ago

Great to know you found a fix. I'll try giving mine a bath. Although when riding I don't wear it but mount it using the Garmin watch handlebar mounts.

0 GeoffR over 6 years ago

I've noticed this "elevation smoothing" issue recently as well. On both runs and rides with downhills followed by uphill sections, it seems to take at least 50-100 feet of climbing before it will start measuring ascent again. Perhaps sweat is the culprit, as this was not an issue for me when it was colder outside. Up until recently, I was very impressed with the elevation measurement during activities (floors climbed is a different story though).

I'll have to give my Instinct a warm bath to see if that corrects the issue.