Incorrect Speed

BrianC
2014-06-13
2014-06-14
  • BrianC

    BrianC - 2014-06-13

    Speed calculations are low by about 4 mph. I have checked files from different sources and they are all low.
    The same .tcx file uploaded to Strava shows the correct speed.
    Is this a configuration setting?

     
  • BrianC

    BrianC - 2014-06-14

    Could someone try this - I could be going mad.
    Load the same file into a different on-line analyser (strava, sportstracker, Garmin) and check a few points on the speed graph. Are they the same. Mine are significantly lower in Mytourbook although the average speed is exactly the same.

     
  • Wolfgang

    Wolfgang - 2014-06-14

    Can you send me an example file and the values which are wrong.

     
    • BrianC

      BrianC - 2014-06-14

      Hi,
      I forgot to mention what a great programme - love it.

      The speed issue is related to the smoothing algorithm I think. If I reduce the "T" parameter and remove additional iterations then the speed graph comes up (but looks spikey. In the attached file I know that I descend the hill at 5.9miles around 30mph.
      If you review it in "ridewithgps" it peaks at 31.2mph but 24.6mph in Mytourbook.

      Thx

       
  • Wolfgang

    Wolfgang - 2014-06-14

    The speed issue is related to the smoothing algorithm I think.

    yes

    When you look at the raw data (without smoothing), the speed is 31.3 mph (see attachment).

    The default 'T' parameter value, which is 10, is a compromise between walking and cycling, for walking you will propably need a larger for cycling a smaller value.

    The value which I use for 'T' when doing cycling is 1.0 ... 2.0 which I think gives a realistic value but you will never get a 100% correct value.

     
  • BrianC

    BrianC - 2014-06-14

    Thanks - I understand.
    :-)

     

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