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elevation calibration help!

Former Member
Former Member over 4 years ago

Anyone have any real suggestions for calibrating elevation/altitude better? I've had my Instinct for a week, I live in Honolulu at sea level, and the elevation is pretty far off. I have tried to auto calibrate, to use the DEM option, to manually input an elevation/altitude. I have taken the time for the GPS soak pre-activity. Nothing has worked. I run my Strava at the same time as recording an activity on the Instinct, and the elevation is quite different than the Strava data. 

I played tennis today for 1 hour, 40 minutes, and during that time, the activity recorded 889 feet of elevation gain (going as low as 2 feet and as high as 201 feet). 

I'm pretty frustrated as I do a quite a bit of hiking in the mountains and need this elevation information. Help??? 

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  • 0 over 4 years ago

    I'm afraid I can't give you a reassuring answer but I have a similar concern in that the elevation over the course of a recorded activity, e.g. running, is quite inaccurate. My concern is that the altimeter might be overriding the GPS: my track is accurate to a meter or so horizontally but can be tens of meters off vertically. The GPS is a 3 dimensional positioning system so height should be to a similar accuracy. On the other hand, an altimeter uses air pressure which can vary for other reasons than elevation gain/loss (hence the need to calibrate).

  • Former Member
    0 Former Member over 4 years ago in reply to DJGShef
    DJGShef said:
    The GPS is a 3 dimensional positioning system so height should be to a similar accuracy.

    I don't have an answer for the OP as I believe this is an issue with the barometer and its port location, but this comment caught my attention and it's a misconception by many.  Note that Garmin even addresses this on its support website by stating GPS elevation is accurate to + or - 400 feet. 

    eos-gnss.com/elevation-for-beginners

  • 0 over 4 years ago in reply to DJGShef
    DJGShef said:
    The GPS is a 3 dimensional positioning system so height should be to a similar accuracy.

    The vertical accuracy of the GPS system is almost an order of magnitude worse than the horizontal one, so the direct calculation of the elevation from GPS is not that much useful. What works better, is the topographic elevation (the DEM - Digital Elevation Model). If you find that your barometric elevation profile shows unexpected data, simply enable the option Elevation Correction on the page of the concerned Activity in Garmin Connect Web, and the profile will be recalculated using the topographic data instead.

  • 0 over 4 years ago in reply to trux

    Thanks and Former Member I didn't realise this was the case. I think my old handheld Garmin must have had the correction data 'on board' as it did a good job with elevation, without an altimeter.

    The Elevation Correction works fine thanks though again, it's a shame it can't be done automatically so that the corrected data can be sent to Strava etc. on syncing.

    Sorry to the OP for hijacking this post but it doesn't look like the barometric issue is going to get resolved satisfactorily with the Instinct so we shouldn't go flying any planes at night!!

  • Former Member
    0 Former Member over 4 years ago in reply to trux

    Thank you for taking the time to jump in with this answer. Two further questions:

    1. I see that elevation correction is turned off with the Instinct since it has a barometric altimeter. Is there a way to just turn this automatically on so I don't have to correct every activity? 

    2. Is there a way to correct this on the app and not have to use the web? 

  • 0 over 4 years ago in reply to Former Member
    Is there a way to just turn this automatically on so I don't have to correct every activity? 

    No, you have to turn it on manually at each activity separately (unless you can write a browser extension doing it for you).

    Is there a way to correct this on the app and not have to use the web? 

    Currently not