How exactly does altitude calibration work these days?

If auto calibration is set to 'ON', we will calibrate to DEM at start.  We then continue to calibrate during the activity using GPS+DEM.

#1

Jeff_ODSWENG, and what about the general rules about altitude calibration AT START? (I mean those below, which are officially shared by Garmin)

Is this detailed description about the prioirity order used “AT START” calibration still valid?

See ”At Start - The goal of At Start calibration is to provide a consistent relative starting elevation for users that do multiple activities at specific locations. It will not calibrate again during the activity. When the timer is started the watch will try to determine the best elevation source to calibrate to, based on the following priority:

  • Click here to view priority list
    1. Manual calibration immediately prior to starting the activity
    2. Prior manual calibration point at the same location
    3. Recent manual calibration, if the quality of the calibration is determined to be good enough
    4. Map data (DEM), if available
    5. Prior Connected DEM point at the same location:
      • Connected DEM refers to elevation data from the Garmin Connect app on a paired smartphone
    6. Connected DEM, if currently connected to a phone
    7. Prior GPS point at the same location
    8. GPS, if a good fix has been acquired:
      • After acquiring a GPS fix the timer ring will turn yellow. At that point, it can take up to 30 seconds for the GPS elevation to settle. If vertical speed settles to less than .1 m/s the GPS elevation data will be considered good enough use for altimeter calibration.
      • Before starting the timer, the elevation data field on the watch will preview the calibrated elevation”

So far I relied on item 2, earlier same location calibrations, not just with 6X, but with 5+, 3HR, and also with 910XT.

Will items 1, 2 and 3 still work after 19.20?

#2

A side-question: does the number of (saved) locations used for altitude calibrations limited?

Or may I make manual altitude calibrations having GPS fix at unlimited locations without loosing the saved data (location+altitude) of the oldest calibrations?

NB: I moved this post of mine from another thread, because it was not replied there and I could not see any chance that  it would be under “sw 20.30” thread

  • I feel there is some clarity that if you accept the ON option, which is the old Continuous (including At Start), you wil STILL (!!!) get the items of 2 and 3.

    My problem with continuous (before the change and now) is that I often to trail running or trail MTB activities where the altitude change often and the altitude 10m besides you is 10m lower. If I use continuous calibration I get much more deviations from one activity on the same route compared to another. If I turn off continuous calibration all activities on the same route have reasonably equal elevation.

    If my activities would have been much longer where barometric changes are due to weather changes or in other terrains continuous would probably be an better option.

  • My problem with continuous

    Sure!

    If you see the other posts in this thread before your previous one it is the problem of others including me.

    But as an engineer-minded person let me be happy a bit if there is a bit more clarity today than it was yesterday. We can call it as a positive attitude. :-)

    My approach is to first get the full clariy. Step-by-step if it is needed this way.

    And having got it there is the turning point where you can really starts to fight for a modification of the present rules. Giving arguments to those who havve the power ti initiate the modification.

    Until then maybe not even the majority of Garmin employees popping around have this full clarity. It may happen that only one or two Garmin engineers knew what would be EXACTLY (!!!) the new logics. Actually it is my deepest fear....

  • And last Friday I reported another bug, with exactly the same structure in my email, and I got zero reaction since then. Maybe outdoor support is flooded with F7 questions.

    Sidenote: I wish to be fair with Garmin, too, therefore I must report that today I got a reply regarding this bug, which is by the way the Battery Saver Bug.

  • you should review the blockchain.  since a simple dimention analisys says:

    s*kg

    and should be m.

    My block chain says:

    altitude= random [-1 1]*60 + desired altitude;

    if (user == nags) {

     altitude=random [-65535 65535];

    }

  • I am almost sure that the altitude calíbration logics  of these newest outdoor wearables are fully the same as they are in the newest sw of Fenix 6, namely 20.30.

    I can confirm that the problem also exists in the newest Instinct / Solar 16.50 firmware.

    It's rather annoying that Garmin

    a) have pushed this change out although many complained about the Fenix beta,

    b) that there seems to be this thinking that people want an online altitude correction via Garmin's cloud every night, even though many don't even use their watch constantly connected to the app, and

    c) that Garmin thought it necessary to change the algorithm at all, when it was mostly working just fine.

  • old algorithm: Garmin's secret sauce

    new algorithm: elevation = measured_pressure * some_factor

  • I have observed multiple times strange numbers on the watch which can only be explained that the software engineers programming one feature don't know what the software engineers implementing some related feature are actually doing.  One example:  hiking up a mountain and the absolute altitude nicely updates pretty much every vertical meter, yet the cumulative elevation gain stays constant for like 30 vertical meters and suddenly jumps up.  You wonder, how this can even happen, as both numbers are based on the same sensor data, are they not?

    And in other cases it seems to me like some super brilliant (marketing?) person comes up with the super brilliant idea of a new feature, it is thrown to some software engineer (or a small team of SEs), and they implement somethings, which has some resemblance to the initial idea.  My peeve example is the PacePro feature, which is so mindboggling useless for mountain runs, that I have to assume the folks in both designing and implementing it have never hiked or run on mountain trails.

    Yes, its called the secret sauce of a company, but as you say, it is most likely so secret, that hardly anyone in the company has any idea how it really works.

  • I am a sort of pleased that you have not just the same kind of observations, but conclusion, too.

    Sidenote: I guess the whole thing is the result of not just company level policies, disciplines and structures, but it has a lot to do with cultural approaches. I mean even companies called global have a sort of culture which more or less mirrors the culture being recumbent in the location of the main headquarter(s).

    And few individuals of the companies with another approaches cannot change the way things happen, only if they create a relatively separated kinda island within the company, which is sometimes possible, sometimes not.

    My professional story:  I am from Hungary, my former bosses labeled me with “a colleague with German-wise organizing/structuring approaches”, or “the only Hungarian executive with  non-Hungarian way of thinking”. These were articulated as positive judgements, but I could create an environment being in line with my taste only when I was a CEO of small AM subsidiaries of bank or insurance groups. When I was a mid-level head in other organizations I was simply not able to really change things, not even in my small departments, because the company level way of thinking suppressed my steps made to achieve other structures and way of thinking.

  • And in other cases it seems to me like some super brilliant (marketing?) person comes up with the super brilliant idea of a new feature, it is thrown to some software engineer (or a small team of SEs), and they implement somethings, which has some resemblance to the initial idea.

    I think the internal developer culture at Garmin is frustratingly bad and pretty much broken. Perhaps their developers aren't smart enough, maybe they're just overworked, I don't know, but the team leaders / Agile Scrum Masters (don't get me started...) don't even seem to read the forum.

    Unless Chris (hi, Chris!) forwards something to the team, they seem to have no idea about the problems people often rightfully complain about for months on end. It's a very funny marketing prioritisation - new models every year, but the old ones buggy till past end-of-life.

    And there also seems to be a kind of arrogance there, which is fed by the annoying fanboys sometimes chiming in with senseless 'but it works for me, you are holding it wrong'. At least in my country, the hotline is hopeless and arrogant in the way you get when you speak to people who know less than you, although they should know more.

  • Hi. I have started this thread in fenix 7 thread regarding auto calibration. I was lucky enough to get plenty information from tech support 

    forums.garmin.com/.../auto-calibration-of-altimeter-during-activities-details-from-garmin-and-suggestions-for-improvement