Ascent calculation error — TomTom Community

Ascent calculation error

IshiIshi Posts: 32 [Outstanding Explorer]
Hello

Have a look at this run: https://mysports.tomtom.com/service/webapi/v2/activity/perm_Udp_6m6_-SlhviR-X2sAXP12xWkqMBUbNgFII5EmOK0igWrPfszNvJwn2b4xAoAo9EDe--CpG2BTguxiMJuWqg?format=html

5 km uphill: almost continuously and then down

Starting elevation was at 927 m, highest was 1244 m but report shows an ascent of 899m!

Doesn't make sense

Thanks for any thoughts/info

Comments

  • tfarabaughtfarabaugh Posts: 16,181
    Superusers
    Ascent is cumulative, including all ascent, not just from the highest point to the lowest point. If you go up 5 meters and then down 5 meters, you had 5 meters of ascent, even though you are at the same elevation you started at. Even on a straight incline there will be small ups and downs it detects (and I see plenty of them in your graph) which add up over time. Plus GPs is only accurate to within 15-20m of your true location so it is picking up points below you and above you, adding to the elevation gain. This is the nature of the technology, it is showing your relative position and estimated ascent totals.

    I hope this helped answer your question. If so, please mark it as a solution so others can look for it if they have the same question.
  • IshiIshi Posts: 32 [Outstanding Explorer]
    I did notice the small ups and downs, however, how can they be twice the net gain in elevation? I think the fact that it is picking up points next to me (as this was a road on a hillside) made the inaccuracies

    Thanks anyway
  • tfarabaughtfarabaugh Posts: 16,181
    Superusers
    Ishi wrote:
    I did notice the small ups and downs, however, how can they be twice the net gain in elevation? I think the fact that it is picking up points next to me (as this was a road on a hillside) made the inaccuracies

    Thanks anyway
    It is likely a combination of both. I had a run along a cliff once and it picked up a point 15 meters to my left, which was unfortunately 500 feet below me, so it added that ascent. It does not filter out extraneous points like that very well. There is not much to be done about it. I upload all my runs to Strava and find their elevation is the most accurate.

    I hope this helped answer your question. If so, please mark it as a solution so others can look for it if they have the same question.
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