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over 3 years ago

Activity.Info.altitude uses barometric pressure for altitude and falls back to GPS altitude while Position.Info.altitude is GPS only.

Playing back fit file in simulator

I can't help myself, but info.object values do not match what I see in fit file (when viewing fit externally)

Even I take tcx file (so I can read it), convert it to fit, play it back in simulator I still see different values, esp for elevation (at least that's what I care about). These are not completely different values, it's like 50-100m off, but I see no reason why this is happening. Is it known behavior? 

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  • Honestly - I gave up on exploring what's exactly the difference. My data field app (number of ski lifts taken) seems to work fine on 3 fit files I recorded earlier this year despite those differences, I'm about to test it on real device soon now. Unfortunatelly it means 1 test = 1 day of skiing -> not many tests per year possible.

    But I can relate to your calculations - it matches with my observations, though I didn't took notes properly, so I can't confirm.

  • I wrote:

    For my .fit e.g.
    Activity.Info.altitude = 14.397258 (wrong?)
    Position.Info.altitude = 32.592106 (seems to be correct and near at the value in .tcx)

    ----------

    The reason for the difference may be the initial value of Activity.Info.altitude = -17.998905

    Therefore it's calculated:
    Activity.Info.altitude = -17.998905 + 32.592106 ~ 14.397258
    Position.Info.altitude = 0.0 + 32.592106 = 32.592106

    The difference remains constant while replaying the .fit .

    @jannk3: Do you've also a constant difference?

  • Never seen other files damaged or a device getting bricked due to a CIQ app in the 5 years I've been doing CIQ.  When it comes to calibrating, that is something I'd do on a real device, using println calls and a log file.

  • I use a Fenix 5 with baro altimeter.

    If replaying a .fit one would expect that the stored values are replayed. I think it's not an insufficiency of the sim, but rather it's simply a bug.

    My app runs correctly on my F5 but I want to calibrate some parameters and look what happen to the results.

    Testing on a real device may be the final testing because it can be troublesome and need much caution. It's possible to damage other files or installations if there is something errorneous or you wrongly delete something e.g. the app runs out of memory or bricked device.

  • the 945 has a baro.

    And yes, testing on a real deice takes more time.

    But remember the simulator is just that.  It's not a full emulator.  You'll see a few differences at times.