Spark- way too much elevation on my cycle activity — TomTom Community

Spark- way too much elevation on my cycle activity

ou999ou999 Posts: 74 [Prominent Wayfarer]
I just finished a cycle run. My iPhone, the Garmin 510 of my friend and his Microsoft Band showed we had around 1.050m of elevation. That was as expected, as our camp site is at 600m and the highest point of our route was at 1.590.
However, TomTom MySports shows an elevation of 1.829 meters. That's way too much. I do not understand this, as the route seems to be recorded correctly. As the altitude and elevation is added by TomTom afterwards, this shouldn't happen I guess. What could be the cause of this? Is this a bug in the TomTom server software? How can I correct this?

This happens with my TomTom Spark Cardio+Music, with fw 1.3.27. The MySports version atm is mysports-v2.20.2-2-4894ecf. I'm happy to help solving this and I have no problem sharing my ride with the people who want to investigate this.

Comments

  • tfarabaughtfarabaugh Posts: 16,181
    Superusers
    ou999 wrote:
    I just finished a cycle run. My iPhone, the Garmin 510 of my friend and his Microsoft Band showed we had around 1.050m of elevation. That was as expected, as our camp site is at 600m and the highest point of our route was at 1.590.
    However, TomTom MySports shows an elevation of 1.829 meters. That's way too much. I do not understand this, as the route seems to be recorded correctly. As the altitude and elevation is added by TomTom afterwards, this shouldn't happen I guess. What could be the cause of this? Is this a bug in the TomTom server software? How can I correct this?

    This happens with my TomTom Spark Cardio+Music, with fw 1.3.27. The MySports version atm is mysports-v2.20.2-2-4894ecf. I'm happy to help solving this and I have no problem sharing my ride with the people who want to investigate this.

    Elevation is calculated off the GPS points collected using a Digital Elevation Model. The elevation will only be as good as the GPS points collected and the accuracy of the model used. Since every device is collecting different GPS points, it is not unusual for the numbers to differ, as they each use different smoothing algorithms, elevation corrections and elevation models. Unless one of them has an altimeter in it (which has been calibrated to a known elevation) then it is really just an estimate. It is not a problem with the watch or the software, but a combination of a number of factors. As an example, you might have data point that is 20m to your right down a hill while your partner's device at the same time collects one 20m to the left up a hill. The elevation discrepancy between those points can vary drastically. Take that and multiply it by a GPS point collected every second and the discrepancies can add up over time. It may also be in how the various softwares are expressing it, some may be showing cumulative gain as the difference between the highest and lowest point whereas others (like TT) are adding all the gain together, so if you go up 100m, down 100m and then up another 100m it is 200 m of gain although you only gained 100m in true altitude. You just have to pick the one you trust the most and stick with it (I find Strava tends to be the most accurate).

    I hope this helps, please let me know if this answered your question. If it did, please mark it as a solution so others can look for it if they have the same question.
  • ou999ou999 Posts: 74 [Prominent Wayfarer]
    Of course there is a reason TT shows wrong figures.
    - also Strava and the other apps show the total elevation gain. Worh my activity, Strava btw uses the elevation from TomTom, as it is exactly the same
    - if the elevation was really 1.829, I was currently not typing on this forum but cycling in the Tour de France. The data is just plain wrong
    - The reason it is incorrect is not important; I want a solution
    - as long as this bug exists, I cannot use my TomTom for cycling in the Alps. At least, I need another device to track the elevation gain
    - visually, there are no wrong gps points on the map. I just follow the road. This is also shown by the altitude graph. That graph just shows a more 'bumpy' ride.
    - Strava recognizes all the segments, so it should be possible to correctly calculate the elevation.

    Do you agree this behaviour makes it useless for cycling in the mountains?
    What can I do to solve this bug?
    Do you know if TomTom is aware of this bug?
  • tfarabaughtfarabaugh Posts: 16,181
    Superusers
    ou999 wrote:
    Of course there is a reason TT shows wrong figures.
    - also Strava and the other apps show the total elevation gain. Worh my activity, Strava btw uses the elevation from TomTom, as it is exactly the same
    - if the elevation was really 1.829, I was currently not typing on this forum but cycling in the Tour de France. The data is just plain wrong
    - The reason it is incorrect is not important; I want a solution
    - as long as this bug exists, I cannot use my TomTom for cycling in the Alps. At least, I need another device to track the elevation gain
    - visually, there are no wrong gps points on the map. I just follow the road. This is also shown by the altitude graph. That graph just shows a more 'bumpy' ride.
    - Strava recognizes all the segments, so it should be possible to correctly calculate the elevation.

    Do you agree this behaviour makes it useless for cycling in the mountains?
    What can I do to solve this bug?
    Do you know if TomTom is aware of this bug?

    I am not sure it is a bug as so far there is one instance of the issue. Until it is shown as a repeatable error driven by the watch software or hardware it is not necessarily something they can address. I do not agree that it makes it useless for cycling either. Does it somehow make the effort null and void? Did you not complete the activity whether you knew the elevation was correct or not? If you can get what you consider the correct data from other sources, what is the impact? It doesn't stop your bike from working, it is just not giving you a single data point in the format you want. Annoying, yes, undoubtedly, and it should be fixed if it is a fault in the watch or the DEM they are using, but to say that it makes it impossible to cycle in the mountains is a reach. It makes it less desirable for you based on specific data needs you have, it doesn't do the same for everyone.
  • ou999ou999 Posts: 74 [Prominent Wayfarer]
    tfarabaugh wrote:
    I am not sure it is a bug as so far there is one instance of the issue. Until it is shown as a repeatable error driven by the watch software or hardware it is not necessarily something they can address. I do not agree that it makes it useless for cycling either. Does it somehow make the effort null and void? Did you not complete the activity whether you knew the elevation was correct or not? If you can get what you consider the correct data from other sources, what is the impact? It doesn't stop your bike from working, it is just not giving you a single data point in the format you want. Annoying, yes, undoubtedly, and it should be fixed if it is a fault in the watch or the DEM they are using, but to say that it makes it impossible to cycle in the mountains is a reach. It makes it less desirable for you based on specific data needs you have, it doesn't do the same for everyone.

    I agree, this does not make the watch totally useless. However, I really like Strava and I would love to have the figures computed over there to be correct.
    Today. I had the same issue. I guess it is because of the lack of details of the shape of the earth's surface. At least, Strava is clear about this and tells that especially in the mountains the resolution of the data they are using, is actually too low to add the correct altitude afterwards. I don't know if TomTom and Strava use the same database, but it seems logical to me this is the case.
    For me, it would be great if I:
    - the resolution of the earth's surface would be increased
    - I could connect my iPhone as an altimeter to my TomTom, so it would record the elevation and altiude during the run and thus this would increase the precision of the measurement.

    What do you think, could this be the cause? Or do you think the database TomTom is using already has a high resolution?
  • tfarabaughtfarabaugh Posts: 16,181
    Superusers
    ou999 wrote:
    tfarabaugh wrote:
    I am not sure it is a bug as so far there is one instance of the issue. Until it is shown as a repeatable error driven by the watch software or hardware it is not necessarily something they can address. I do not agree that it makes it useless for cycling either. Does it somehow make the effort null and void? Did you not complete the activity whether you knew the elevation was correct or not? If you can get what you consider the correct data from other sources, what is the impact? It doesn't stop your bike from working, it is just not giving you a single data point in the format you want. Annoying, yes, undoubtedly, and it should be fixed if it is a fault in the watch or the DEM they are using, but to say that it makes it impossible to cycle in the mountains is a reach. It makes it less desirable for you based on specific data needs you have, it doesn't do the same for everyone.

    I agree, this does not make the watch totally useless. However, I really like Strava and I would love to have the figures computed over there to be correct.
    Today. I had the same issue. I guess it is because of the lack of details of the shape of the earth's surface. At least, Strava is clear about this and tells that especially in the mountains the resolution of the data they are using, is actually too low to add the correct altitude afterwards. I don't know if TomTom and Strava use the same database, but it seems logical to me this is the case.
    For me, it would be great if I:
    - the resolution of the earth's surface would be increased
    - I could connect my iPhone as an altimeter to my TomTom, so it would record the elevation and altiude during the run and thus this would increase the precision of the measurement.

    What do you think, could this be the cause? Or do you think the database TomTom is using already has a high resolution?

    What I find odd is that Strava agrees with the watch. Strava does all of its own calculations from the base GPS data, applying its own algorithms and elevation corrections (which is why the distance and pace are often different) so the fact that it matches makes me wonder. I have never had Strava agree with my watch for running, but maybe it is different for cycling. But is sounds like Strava is not even trying to come up with their own elevation.

    There is no way to link your phone to the watch, that is not the way the BT works and it would not know what to do with the data (there is no code in place to use and external altimeter). Plus only iPhone 6 and greater even have a built-in altimeter.
  • BobCatMaxBobCatMax Posts: 22 [Master Traveler]
    Have you gone back to the activity after 24hrs+ ?

    I seem to recall some activity logging sites recalculating elevation from map data once the ride has been logged but it took a while. Can't remember if Strava did it
  • IrossettoIrossetto Posts: 2 [Apprentice Traveler]
    I totally agree with ou999. I was used to use a simple Nike atmospheric altimeter which accuracy is pretty good. With Spark3 the figures are totally different. It looks like TT multiplies the elevation x2. This is totally unacceptable. I can't use two devices, guessing which one is the more reliable.
    I am very disappointed as I bought two TT (me and my wife) and convienced friends to buy it too.

    Soo bad !!!!!!!!!!!
  • yannouyannou Posts: 1 [Apprentice Traveler]
    I see exactly the same phenomenon with my Adventurer: if I look at the elevation profile in TomTom sports or Strava, they match pretty well. But the ascent/decent number in TomTom (or directly on the watch) is always way bigger than Strava's, which seems much closer to reality given the profile. See here: https://www.strava.com/activities/975701794. This is 502 m elevation gain in Strava, while TomTom sports reports Ascent 1,201 m, Descent 1,188 m (https://mysports.tomtom.com/app/activity/127377788/). It happens on every hike.
  • ShushuShushu Posts: 1 [Apprentice Traveler]
    I have a similar problem. I have taken part in a three day mountain bike race, with an properly measured daily ascent. My Tomtom indicated a far geater reading each day. Tomtom has a problem with these type of readings, and all they can do is to explain why it is so. The simple way to fix it is to adjust your software. Please make a plan!!
  • Ferry MichaelFerry Michael Posts: 5 [Master Traveler]
    I use my TomTom Runner 2 in freestyle mode while sea kayaking. It gives very strange and crazy elevation changes, e.g 28 metres of ascent over 500 metres travelled on open sea 2km from land and a total ascent recorded of 421 metres over a journey of 9km on a calm sea. Some of the ascent may be attributed to paddling around Bass Rock that is around 100 metres high with near vertical cliffs but the heights recorded do not correspond with that, and some occur some distance away from the rock. There were a couple of points where we paddled into caves under the rock, but these do not correspond with peaks in altitude. Another trip has recorded an instantaneous 50 metre accent mid way in a sea crossing.
    https://mysports.tomtom.com/app/activity/154172860/
  • Davitom84Davitom84 Posts: 1 [Apprentice Traveler]
    same problem here with my adventurer
  • bobbybillbobbybill Posts: 1 [Apprentice Traveler]
    I too get these same problems.

    When I cycle hills that friends have cycled with Garmin, my tomtom recordings of elevation gain are way higher. - I thought I was climbing much higher until I compared results :(

    Please sort it out. It is not exactly a cheap product and I would like to get what I was promised.

    Off topic: The battery life and storage is very disappointing. Great for my morning runs and short cycles, but when I did a 100k one day it didn't record the end, so now having to use a phone for such trips and just use it as speedo and cadence. I bought it hoping to avoid taking a phone.

    Rob
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