Endomondo and height gain

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  • Endomondo and height gain
  • rob jackson
    Member

    Did a route yesterday – involved 2800ft of climbing, endo reports it at 1800ft, a road ride is stated as 1637ft of climbing but in reality was 3212ft.

    am i reading something wrongly?

    iDave
    Member

    you weren’t going fast enough

    Premier Icon MSP
    Subscriber

    I don’t know how the endomondo metrics work, but I always found they massively overestimated flattish rides, and underestimated mountainous rides.

    LoCo
    Member

    Had my first go with Endo, this weekend and it seems ok but not that accurate as the route was a fair way, 1/2 mile ish off, in places and not convinced the heigth gain was right either, the readings on my phone and computer were different too. πŸ˜•

    bob_summers
    Member

    I must have too much time on my hands… I uploaded the same track recently onto EM and a few other sports tracker sites (RideWithGPS, Strava, etc).
    EM reported altitude gain as 1450m, the others (correctly IMO) report more or less 2000m, also as reported by my Edge 705 at the time.

    Not sure why they should behave differently.

    retro83
    Member

    Not convinced it’s recording the data correctly.

    Went out and did a ride up and down a hill a few times, ended up with a reading of 50m up and 140m down.

    Next time I’m out I’m going to see if you can run MyTracks and Endo at the same time and see if the numbers look the same.

    Premier Icon Bez
    Subscriber

    Anything that records altitude data from GPS will be massively inaccurate. GPS is designed to be accurate in latitude and longitude but not in altitude. If you want accurate altitude data you need a barometric altimeter. The problem is not Endomondo, it’s that you don’t have an altimeter.

    Premier Icon seosamh77
    Subscriber

    it’ll be recording the data fine, it’s the reader that will be interpreting it wrongly.

    I find if you load a gpx in to different programs you’ll get different results. I prefer google earth as that gives you bigger values! πŸ™‚

    Premier Icon MSP
    Subscriber

    Not sure why they should behave differently.

    They all use different algorithms to work out the height gain/loss.

    The unit records data at a set point, ie every 10 metres, which includes location and altitude, the software then fills in the blanks to estimate the actuall height gained, so it always only an estimate.
    On top of that, getting altitude just from a gps signal is very inaccurate.

    Premier Icon Bez
    Subscriber

    I find if you load a gpx in to different programs you’ll get different results.

    Probably because they’ll take a variety of approaches to deal with the fact that the incoming data is crud. For instance, some will leave it unaltered, some will replace the altitude data with figures interpolated from a known height map, others may use some algorithm to try and massage the data, etc. But fundamentally, if the altitude’s come from a GPS signal, it’s not accurate.

    Premier Icon andytherocketeer
    Subscriber

    I don’t know how the endomondo metrics work

    I think the problem is we don’t know how any of the metrics work. Well other than riding up a very uniform hill (ie all up, with no up/downs), and reading the values off a paper map.

    The following is from a previous post of mine on a previous thread. Exactly the same track loaded to 2 websites gives pretty much identical lowest and highest elevation readings, but the total climb/descent is vastly different. That’s for a pretty flat ride, so no idea what that would do to a hillier ride
    At least one of them is wrong πŸ˜‰ but which? or both?
    My guess is that Endomondo smooths data a lot more.

    Endomondo says:
    Min/Max Altitude = 114m / 207m
    Vertical Up/Down = 67m / 86m
    Max/Avg Speed = 35kph / 16.9kmh
    Distance = 19.65km

    Everytrail says:
    Min/Max Altitude = 113m / 207m
    Vertical Up/Down = 162m / 175m
    Max/Avg Speed = 43.7kph / 16.9kph
    Distance = 19.6km

    edit: the above was from an etrex vista hcx with baro alt rather than smartphone

    nealy
    Member

    Strava is much better with altitude calculations, try exporting the GPX file from Endo into Strava and see what it makes of it.

    Premier Icon Bez
    Subscriber

    Endomondo says:
    Min/Max Altitude = 114m / 207m
    Vertical Up/Down = 67m / 86m

    Endomondo’s clearly doing something stupid when massaging the data then, because (assuming that’s a contiguous track) you can’t go between 114m and 207m without either doing more than 67m of climbing or 86m of descending.

    FWIW I did one ride this year where Endomondo claimed a little over 1000m of climbing and the barometer said a little over 2500. Which gives some idea of how far off the combination of GPS altitudes, low sample rates and dodgy data massaging will be.

    Premier Icon andytherocketeer
    Subscriber

    Bez – true. Assuming that the 114/207m are also correct (the fact that Everytrail picked out the same numbers suggests it might be, although they might both be picking up on the same duff point). Need a map with accurate contours to compare.

    I’ll stick the same track in to Strava and some others, but I bet it’ll be different to Everytrail.

    rob jackson
    Member

    So whats the answer

    Premier Icon Bez
    Subscriber

    So whats the answer

    What’s the question?

    chrismac
    Member

    So whats the answer

    Simple, go out, enjoy your ride and dont worry about the differences. If youve had a good day out on the bike, who really cares which figure is correct.

    Premier Icon Bez
    Subscriber

    Bez – true. Assuming that the 114/207m are also correct

    It doesn’t matter whether they are or not – point is, Endomondo’s doing some data massaging that churns out contradictory figures, which is stupid.

    Premier Icon richmtb
    Subscriber

    I’ve always taken Endomondo’s altitude figures with a pinch of salt. The more up than down on a circular route phenomenom says it all really.

    I’m happy that it seems pretty accurate for distance

    I found that my garmin (almost) exactly matches the OS maps for height gain/lost. But if you upload it to the garmin site it defaults the USGS mapping which appears to have really broadly spaced contours and always gives a height arround half to 2/3 of the actual garmin.

    There is a tick box to select the gps based altitude or the map based altitude though so if you dont tick that it retains the ‘correct’ data.

    No idea for endomondo though.

    Premier Icon jambalaya
    Subscriber

    In my opinion Endomondo can’t do altitude because it is not being fed good data. In my experience of using GPS over the past 10 years GPS devices cannot do altitude (eg it says we are at 100m when we at sea level). I have a Suunto watch which does altitude logging well and I just reference that if/when I want to know height info. FYI the watch has to be calibrated as the air pressure changes with the weather and it uses air pressure to determine altitude. So in my view the phone or your GPS has little chance of being accurate.

    Premier Icon andytherocketeer
    Subscriber

    more up than down

    Is quite common, regardless of whose tools you use. Unless you’re pretty good at riding up/down at pretty similar speed, there’s a lot more datapoints on the ups than on the downs, so you get asymmetric stats. Walking/running ought to be better (I guess).

    I take *ALL* the stats with a pinch of salt (other than difference between 2 contours on a hill).

    PS MapMyRun came out with near identical figures to endomondo (so another favourite == more BS than others). GMaps suggests 114/207m might be about right (although they’re not definitive maps). Will try Strava tonight, since that’s everyone’s favourite for hills πŸ˜‰

    Premier Icon Bez
    Subscriber

    FYI the watch has to be calibrated as the air pressure changes with the weather and it uses air pressure to determine altitude.

    Only if you want absolute figures. If you’re only interested in height gain then it doesn’t matter if all the samples are out by the same amount.

    Premier Icon Bez
    Subscriber

    Bottom line is:

    – if you really care about altitude, get a barometric altimeter, use software which doesn’t massage or replace the altimeter’s data, and ensure your altitude data is sampled at high frequency (ie evey few seconds)
    – if you don’t have an altimeter but you’d still like half decent altitude data, your next best bet is to use software which can replace the altitude data in your track with data derived from a trustworthy (USGS, OS etc) set of altitude data; again, you will lose accuracy with lower sample rates
    – if all you have is GPS data then forget it; regardless of sample rate, altitude readings are never going to be reliable in the first place

    Premier Icon andytherocketeer
    Subscriber

    OK update of my earlier post. Identical GPX file, barometric, uploaded to 4 different sites.

    Endomondo says:
    Min/Max Altitude = 114m / 207m
    Vertical Up/Down = 67m / 86m

    Everytrail says:
    Min/Max Altitude = 113m / 207m
    Vertical Up/Down = 162m / 175m

    MapMyRide says:
    Min/Max Altitude = 112m / 195m (by mouseover of plot) or 210m (reported in summary)
    Vertical Up/Down = 75m / 85m (assumed that end is 10m below start, which is about right)

    Strava says: (with a bit of jiggery pokery to get it to actually report anything)
    Min/Max Altitude = 108m / 205m
    Vertical Up/Down = 226m / 237m

    Now I know why people like Strava πŸ˜‰
    Maybe I’ll start playing with that again, too πŸ˜‰

    Clearly Endomondo and MapMyRide/Run (ie 2 of the most popular sites) have filtered (or done something to) the data well beyond the point where the maths make sense. Will file a bug report I think πŸ˜‰

    Before I trust Strava, I want to do a loop in Holland.

    edit: and for reference, the min/max elev values in the GPX file are:
    113.568m
    207.356m

    Premier Icon andytherocketeer
    Subscriber

    Strava is much better with altitude calculations, try exporting the GPX file from Endo into Strava and see what it makes of it.

    Oh, and reverse engineering the data for my file above…

    Everytrail just sums the total up/down in the file, which means Strava must be making up some elevation gain/loss from somewhere πŸ˜‰

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