Altitude

Iceman1

Hello,
I have a question about the altitude readings in the activities. When I start and end an activity at the same place, often (not always) the altitude doesnt match. Is it the same for everybody else aswell?
I dont calibrate the altitude before running, it shouldnt be necessary right?

mikekoski490

@Iceman1 Depends on a few factors but just know it’s normal.

Your altitude might be off to start, and elevation correction might factor in during your workout. Or,

If you do a long adventure, sometimes significant changes in barometric pressure can impact the readings.

This is regular for ANY watch/instrument that relies on a pressure sensor for alti/baro readings.

Iceman1

@mikekoski490

I was under the impression that this function altifuse or fusedalti (??) was supposed to go back and correct the altitude for the whole activity. Possible that i have misunderstood this though
My activities (running) are normally only between 40-60 minutes, so the preassure changes from weather is likely not an issue for me.

Anyway, thanks for the reply!

colinmacdon

@Iceman1 Fusedalti will go back and correct prior readings (this was confirmed by other members). I observed this too–my elevation was way off at the start, I watched elevation during the entire activity on the watch, and at about 15 mins in, the elevation was corrected, and also back-corrected in the app…i.e. elevations reported in the app were very different from what I saw in the first 15 mins.

mikekoski490

@Iceman1 Fusealti does indeed help! It’s not perfect though, but waaay better than before it.

Egika

@Iceman1 can you specify of which difference we are talking about here? How many meters over how many hours of activity?

Iceman1

@Egika

Hi,
The worst I have seen is start at 0 meters and finish at 23 meters. 10,5km and 58 minutes.
23 meters is close to the correct elevation which I have found out to be ~30meters. This was before the latest update though. I would post a screenshot but i couldnt figure out how to attach it here.

Im mostly running where I live, and its flat here so not that big of a problem. But around here it could be for example start at 1 meter and finish at 8( which is correct elevation) at 40 minutes running. Not a big problem, Im just curious since looking at my friends activities on Strava (using garmin) they all seem to start and end at the same elevation

Brad_Olwin

@Iceman1 Strava often corrects for elevation.

JANTIKAINEN

All of a sudden my Race’s altitude reading (not in activity mode) went totally bonkers.
I’m in an apartment building something like +25-30 meters from the sea level. At first the watch showed correct altitude but today the reading is from -130 to-135 meters.
I wonder what’s going on with the sensor. I restarted the watch but it didn’t help.

mikekoski490

@JANTIKAINEN Check the barometer reading. If there is a super-fast or consequential change in atmos pressure, it can kick it out of baro/alti lock.

So if the baro suddenly changed upwards, it could make your alti readings go down (approx. 10m for every 1 hpa).

As much as there are locks and fused alti on these devices, good to manual check and update every once in awhile.

JANTIKAINEN

@mikekoski490 Thanks for the tip, I didn’t know that.
I did an automatic adjustment based on gps location and the watch corrected the altitude reading.
Since I restarted the watch the baro graph wasn’t anymore available as it looks like it behaves the same as the resources - history is swept. But if I remember correctly I recall there was a spike in the baro graph.

mikekoski490

@JANTIKAINEN Auto adjust is good if you dont know your alti for sure. If you know your current alti, manual is a bit faster and doesn’t drain the battery.

Ya, when you restart the watch, it zeroes the alti/baro graphs unfortunately.

Egika

@JANTIKAINEN depending on where you are based, bigger buildings often have some kind of ventilation control, that will have an influence on the pressure inside the building.
Have you checked if the altitude goes back to normal, wen you are outside?

Otherwise as others suggested, over the period of a few days, altitude can drift due to weather variations as well.

JANTIKAINEN

@Egika Thanks for your comment.
yes, I did try to go outside, but it didn’t change the altitude.
Here in Finland, in the most of the apartment buildings the ventilation system is still gravity based so I don’t think that’s the case here.
Anyway, things are back to normal