Using Racechrono for DH mountain bike runs (and track overlay errors on google earth)

Have been having a ball with the laptimer - created new tracks, imported
data from other GPS thanks for the advice on nmea file imports!!), fixed up the Phillip Island track traps etc. Just got a couple of
questions that you maybe able to help with.

1. When I export the Phillip Island track to google earth it does not overlay properly
over the image (the track sits further north than the image). Is this a
problem with the track data or a curvature of the earth thing or something?
I haven't tried remapping the track but might do this next time I am there.

2. I have created and used tracks for XC mtb successfully and decided to use
the system for DH mtb racing. I walked the track to map it and put the
start and finish lines in successfully but when I put the phone and gps on a
rider (gps in an armband and phone in a bumbag), I got all the right data in
the travelled route but only 1 run was recorded. I tried moving and adding
traps to try and diagnose the problem but could not pinpoint it. Seems to
be related to all the extraneous data from the shuttle runs taking them back
to the top but I would have thought that this would be removed as I made the
traps directional to try to account for crossovers in the routes. Have you
got any ideas for improving this? I can only think of getting him to stop
either the session or the gps at the bottom and start it again when they get
to the top but this just introduces the "error" of remembering to do this.
Is there a way to manually remove the shuttle runs from the data after
collection? I also tried creating the track from the bike data (instead of
my original walk) but it did not make any difference.

thanks for any help.



  • edited March 2010
    1) The satellite images on Google have been offset slightly in some areas. So this is a Google problem.

    2) You should get extra laps for the shuttle runs, not fewer. Make sure the traps are facing the right way, and are correctly positioned. You can use the traveled route and browse traps views to verify this. You should clearly see where the logged data track is going, and where the traps are positioned.
  • Hi,

    I did confirm the trap directions (turned them around and got no laps recorded). If I moved the start and finish closer together (away from the crossovers) I did get 3 laps listed instead of 1 but I am not sure how this helps me to get the full run info. The travelled route shows 5 runs. I tried adding extra splits and got some extra sectors in some laps but not others, but no extra full laps (I got extra lines on the laps table but only with some sectors listed). I downloaded the same data into Qsports software and was able to estimate the run times from the altitude graphs but I can't do any lap setup in this. (Can I add a screenview to these messages to show the travelled route info?)

  • You can email them to me tracks(at)
  • Hi again,

    Did you get to have a look at the data that I sent? (The one with 5 runs on it) I haven't had a chance to try it out again but will be doing some more next weekend.

  • Hi, I'll try to look at the data on Friday.
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