Garmin 520 or strava elevation

shiznit76
shiznit76 Posts: 640
edited February 2018 in Road general
Hi, i am just home from a ride and put data in to strava, my garmin 520 said i had only climbed 820ft, but strava, using correct elevation said 1515ft! Now i would expect a little differenc, but this is almost double! Having did similar run previously using my old gamrin 200 i would say the strava elevation v the 520 is nearer real thing, so is their a problem with my new 520 unit?

Comments

  • N0bodyOfTheGoat
    N0bodyOfTheGoat Posts: 6,057
    GPS computers with barometers often miscalculate the elevation gain, I correct every ride recorded on my Lezyne Super GPS, result can be higher or lower.

    I've seen local rides recorded on Garmins show wonky elevation data, so it's not just a Lezyne thing.
    ================
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  • bondurant
    bondurant Posts: 858
    This is worth a read: http://regex.info/blog/2015-05-09/2568
  • Dorset_Boy
    Dorset_Boy Posts: 7,579
    In hilly / mountainous areas Strava's elevation correction massively over states the elevation gain.
  • ZMC888
    ZMC888 Posts: 292
    Exactly the same here. All I want is for a meter climbed to be a meter climbed (or foot obviously). Garmin seems to undercalculate by about 10%, and Strava overcalculate by about 40%. I really thought we could do better in this day and age. :-(
  • sloppyschleckonds
    sloppyschleckonds Posts: 8,019
    Does it really matter?
    I'm sorry you don't believe in miracles
  • jollygiant
    jollygiant Posts: 117
    My Wahoo Elemnt does this but once you log onto Strava it gives you chance to correct elevation and it gets sorted.
  • mike1-2
    mike1-2 Posts: 456
    jollygiant wrote:
    My Wahoo Elemnt does this but once you log onto Strava it gives you chance to correct elevation and it gets sorted.
    Mine did this yesterday, I actually noticed on the ride that the gradient wasn’t changing on the display, it just stuck at 0%. Took it off the mount and had a look, the holes in the back for the altimeter were blocked with muck (the weather was terrible) gave these a wipe down and it started acting normally again. Only noticed after 30 odd miles so missed out on around 50% of my climbing. Might be worth checking in future.
  • shiznit76
    shiznit76 Posts: 640
    Mike wrote:
    jollygiant wrote:
    My Wahoo Elemnt does this but once you log onto Strava it gives you chance to correct elevation and it gets sorted.
    Mine did this yesterday, I actually noticed on the ride that the gradient wasn’t changing on the display, it just stuck at 0%. Took it off the mount and had a look, the holes in the back for the altimeter were blocked with muck (the weather was terrible) gave these a wipe down and it started acting normally again. Only noticed after 30 odd miles so missed out on around 50% of my climbing. Might be worth checking in future.


    Interesting, asi found mine did this also.Whereare these holes?
  • shiznit76
    shiznit76 Posts: 640
    ok, so after last weeks Strava almost doubling the elevation from my garmin, tonight it is almost halved what the garmin calculated! Really, surely there must be a fault here somewhere?
  • mike1-2
    mike1-2 Posts: 456
    shiznit76 wrote:
    Mike wrote:
    jollygiant wrote:
    My Wahoo Elemnt does this but once you log onto Strava it gives you chance to correct elevation and it gets sorted.
    Mine did this yesterday, I actually noticed on the ride that the gradient wasn’t changing on the display, it just stuck at 0%. Took it off the mount and had a look, the holes in the back for the altimeter were blocked with muck (the weather was terrible) gave these a wipe down and it started acting normally again. Only noticed after 30 odd miles so missed out on around 50% of my climbing. Might be worth checking in future.


    Interesting, asi found mine did this also.Whereare these holes?

    On the back in the bottom third of the device, should be obvious as there are two sets of them. I never had this issue with my old Edge 810, however it was always in a rubber case. Might get one for the Elemnt to see if it makes any difference.
  • sir_les
    sir_les Posts: 13
    I find that if it's raining my 520 is always way out on elevation. Last Saturday it reported around 820ft but after Strava correction was around 3800ft.
  • Yanis Nayu
    Yanis Nayu Posts: 10
    The garmin’s elevation measurement will be low if it’s raining.
  • trivial_poursuivant
    trivial_poursuivant Posts: 1,136
    I wouldn’t trust a Garmin’s elevation. Simply down the amount of rides where my elevation at the start and end are wildly different. Which Considering my start and finish point is my front door makes it unreliable.

    Whereas Strava take their data from survey maps which is more likely to accurate
  • wongataa
    wongataa Posts: 1,001
    Trivial poursuivant wrote:
    Whereas Strava take their data from survey maps which is more likely to accurate
    Err, no. Strava mainly take their base elevation data from satellite generated elevation datasets. Different parts of the world were mapped at different resolutions. In lower resolution areas the resultant info is worse, resulting in many elevation errors. Even in better scanned areas the are artefacts caused by things like buildings trees which introduce errors. Have you ever seen a Strava auto generated categorised climb segment on a flat piece of road? I have. These are due to elevation dataset errors. Strava have been using elevation data recorded on devices with altimeters to improve their elevation numbers for a while as well.
  • trivial_poursuivant
    trivial_poursuivant Posts: 1,136
    wongataa wrote:
    Trivial poursuivant wrote:
    Whereas Strava take their data from survey maps which is more likely to accurate
    Err, no. Strava mainly take their base elevation data from satellite generated elevation datasets. Different parts of the world were mapped at different resolutions. In lower resolution areas the resultant info is worse, resulting in many elevation errors. Even in better scanned areas the are artefacts caused by things like buildings trees which introduce errors. Have you ever seen a Strava auto generated categorised climb segment on a flat piece of road? I have. These are due to elevation dataset errors. Strava have been using elevation data recorded on devices with altimeters to improve their elevation numbers for a while as well.

    It’s still going to be more accurate than the Garmin. As I said before I have had start and finish at different elevations but same point. In other words it’s not accurate at all
  • Dorset_Boy
    Dorset_Boy Posts: 7,579
    TP - I did my first Etape in 2015. My Garmin measured the climbing at 4,386m. I know that had I Strava corrected the elevation it would have come out well in excess of 6,000m elevation. Officially it was around 4,400m IIRC.

    I've ridden the west coast mountains in Mallorca. People recording on their phones had significantly more elevation that those using Garmins.

    I have an 800, my wife an 820 and my son a 510. My son's reads the highest elevation gain and my wife's the lowest on identical rides.

    The Garmins are not 100% accurate, but they are way more accurate than the satellite generated datasets, unless there has been a big change in atmospheric pressure during your ride (that could include stopping off in a steamy cafe) or the route is flat and exposed.
  • trivial_poursuivant
    trivial_poursuivant Posts: 1,136
    Dorset Boy wrote:
    TP - I did my first Etape in 2015. My Garmin measured the climbing at 4,386m. I know that had I Strava corrected the elevation it would have come out well in excess of 6,000m elevation. Officially it was around 4,400m IIRC.

    I've ridden the west coast mountains in Mallorca. People recording on their phones had significantly more elevation that those using Garmins.

    I have an 800, my wife an 820 and my son a 510. My son's reads the highest elevation gain and my wife's the lowest on identical rides.

    The Garmins are not 100% accurate, but they are way more accurate than the satellite generated datasets, unless there has been a big change in atmospheric pressure during your ride (that could include stopping off in a steamy cafe) or the route is flat and exposed.


    So, 3 Garmins, 3 completely different elevation readings. And you’re saying they are still reasonably accurate. Which was is most accurate of the 3 ? Can you answer that?
  • wongataa
    wongataa Posts: 1,001
    Trivial poursuivant wrote:
    wongataa wrote:
    Trivial poursuivant wrote:
    Whereas Strava take their data from survey maps which is more likely to accurate
    Err, no. Strava mainly take their base elevation data from satellite generated elevation datasets. Different parts of the world were mapped at different resolutions. In lower resolution areas the resultant info is worse, resulting in many elevation errors. Even in better scanned areas the are artefacts caused by things like buildings trees which introduce errors. Have you ever seen a Strava auto generated categorised climb segment on a flat piece of road? I have. These are due to elevation dataset errors. Strava have been using elevation data recorded on devices with altimeters to improve their elevation numbers for a while as well.

    It’s still going to be more accurate than the Garmin. As I said before I have had start and finish at different elevations but same point. In other words it’s not accurate at all
    That will be because the air pressure changed during your ride. Altimeters use air pressure to calculate elevation. If the weather changes the reported elevation will change even if you don't move.
  • trivial_poursuivant
    trivial_poursuivant Posts: 1,136
    wongataa wrote:
    Trivial poursuivant wrote:
    wongataa wrote:
    Trivial poursuivant wrote:
    Whereas Strava take their data from survey maps which is more likely to accurate
    Err, no. Strava mainly take their base elevation data from satellite generated elevation datasets. Different parts of the world were mapped at different resolutions. In lower resolution areas the resultant info is worse, resulting in many elevation errors. Even in better scanned areas the are artefacts caused by things like buildings trees which introduce errors. Have you ever seen a Strava auto generated categorised climb segment on a flat piece of road? I have. These are due to elevation dataset errors. Strava have been using elevation data recorded on devices with altimeters to improve their elevation numbers for a while as well.

    It’s still going to be more accurate than the Garmin. As I said before I have had start and finish at different elevations but same point. In other words it’s not accurate at all
    That will be because the air pressure changed during your ride. Altimeters use air pressure to calculate elevation. If the weather changes the reported elevation will change even if you don't move.

    I know. You could bang on about altimeters, pressure, QNH etc. It’s always changing so it’s hardky accurate. Aircraft have to adjust their altimeters to compensate. Depends if they are using flight level 1013 or a local QNH. I know how pressure effects Garmin’s ergo they are not accurate.
  • Dorset_Boy
    Dorset_Boy Posts: 7,579
    TP - mine is the most accurate! First, it's the middle reading, second, it's my device, third it has been very accurate in the mountains, assuming the elevations on the road markers and cols are accurate! :D:D

    I'm not suggesting 100% accuracy for the reasons stated in other posts, but I KNOW that the Garmins are MORE ACCURATE than the Strava elevation corrections, exceptional weather incidents excepted.

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