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Garmin 800 optimistic on height climbed

CotterendCotterend Posts: 73
edited October 2017 in Road general
I've noticed on signposted cols that my Garmin 800 reads about 10% higher climb figures than the signboards indicate.

Does it take height information from the maps, or does it calculate height from GPS triangulation? If the latter, is this a positive error bias? By this, I mean if it reads, say, plus or minus 1m on the real height, when it is plus 1m, it will record a metre gained, but when it is minus 1m, it will ignore it. So, over time, it will keep adding the plus errors.

Does anyone know?


  • davidofdavidof Posts: 2,578
    It has a barometric altimeter - if you have set it up to use this. Otherwise it uses GPS data.

    The Barometric altimeter should be pretty accurate. Weather changes can affect it. My pilot friends tell me they tend to under read even if temperature compensated but we are talking meters over a 1000 meter climb.

    GPS data is less accurate with a tendance to overread (accumulated errors). I wonder if you need to check your settings?
    BASI Nordic Ski Instructor
  • Strava does elevation correction which is useful if you've been out in the rain and your Garmin reports that your mountainous ride was essentially flat. :lol:
  • I had no idea it had a barometer on board! I shall investigate :)

    Thank you.
  • ryan_w-2ryan_w-2 Posts: 1,162
    Elevation is a funny one.

    My Edge 1000 recently said I'd done just shy of 3,000m climbing, whereas the Strava route planner said it should have been around 4,100m... All my others friends Garmins (800, 820 & 500) all claimed around 3,100m.

    I have my Garmin set to 1 sec recording with GLONASS on.
    Specialized Allez Sprint Disc --- Specialized S-Works SL7

    IG: RhinosWorkshop
  • Dorset_BoyDorset_Boy Posts: 4,368
    Strava elevation correction is hugely inaccurate if you are in the mountains, it over reads by about 25% typically.
    My Edge 800 has appeared to be very accurate in the mountains when comparing the elevation markers that are at the side of the road.
    It doesn't however work very well in the rain when the barometer holes fill with water!
    The 510 (my son's) seems to over read by about 5% and the 810 (my wife's) under read by about 5%.

    Strava route planner also over estimates elevation on mountain routes by a large amount.

    If you want to inflate your elevation gain in the mountains, use the Strava app!
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