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Tour de France: GPS Elevation Data Error - will it be fixed?

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    • CommentAuthorFree Memberholocron
    • CommentTimeJul 19th 2009
     
    holocron

    MMR TDF Challenge Staff:

    It has been stated that there is a flaw in your interpretation of GPS elevation data. This appears to specifically effect short steep climbs.

    This significantly effects those of us who live in locations that only provide short climbs that we must repeat to gain any ascent credit.

    1. Are you going to correct this error, so that our ascents are correct?

    2. Are you going to correct this  error and reevaluate previous stages that have been effected by the error?

    Regards.

    • CommentAuthorFree Memberjkundert
    • CommentTimeJul 19th 2009
     
    jkundert
    Indeed I have found this to be true in my area (Athens, GA) which has lots of steep little hills that keep showing up as 2% grades (let me tell you, they are WAY harder than 2%!), and not giving much elevation credit to boot. Would be nice for the mapmyride app on the iPhone to give me more credit for lugging my old body over those hills--they hurt enough.... :)
    • CommentAuthorFree Memberholocron
    • CommentTimeJul 19th 2009
     
    holocron
    jkundert:Indeed I have found this to be true in my area (Athens, GA) which has lots of steep little hills that keep showing up as 2% grades (let me tell you, they are WAY harder than 2%!), and not giving much elevation credit to boot. Would be nice for the mapmyride app on the iPhone to give me more credit for lugging my old body over those hills--they hurt enough.... :)

     It isn't your device. It is the manner in which MMR is interpreting and processing the elevation data. They have identified the flaw. Now they need to fix it so that those of us without "long hills" are on an even field with others.

    • CommentAuthorFree Memberttt68
    • CommentTimeJul 19th 2009
     
    ttt68
    The data that they use must differ when you actually plan out your course using MMR vs. when you submit it to the TDF challenge. Before I took the time to ride it, I plotted a course up a hill with 350+ ft of gain in a mile travel, according to their elevation data. Travelling up this road 10 times should have given me over 3000 ft. But when I submitted it to the TDF/MMR, it said I had 1660 ft of gain. I wonder why the two differ so greatly. I thought it would have pulled the same vertical elevation from one source. Also, the plotted course showed grades of 10-15%. The submitted ride didn't show near this amount. My GPS did show 10-15% in some areas, with an average of about 6%.
    • CommentAuthorFree Memberttt68
    • CommentTimeJul 19th 2009
     
    ttt68
    I don't expect these will be corrected for previous stages since the jerseys have been awarded. But I look forward to it being corrected for next year's challenge.
    • CommentAuthorGold Membershipaea@mmf
    • CommentTimeJul 19th 2009
     
    aea@mmf
    This is a technical challenge which causes an issue that effects a very small minority of rides. From my perspective this is something that needs to be fixed and will be a high priority when we revamp our elevation service. However, I'm not in a position to really comment on when that will be done. I understand your concern and frustrations, and believe me if I had the latitude (hehe, GIS pun) to go and fix this immediately I would.
    • CommentAuthorFree Memberfilosam
    • CommentTimeSep 15th 2009 edited
     
    filosam

    I recently rode the TFCE (The Flattest Century in the East). This century is not flat with many 50-200 foot uphill sections. I rode the 70 mile course and my friend rode the century. He had 3000 feet of climbing indicated by his Edge 705. In the 70 miler my Edge 305 indicated about 2600 feet. I know that the Garmins are not that accurate on the elevation. Inspection of the profile (which looks pretty valid)  indicates well over 1000 feet of climbing. However, MMR indicates less than 300 feet of climbing in each route and the ride profile/elevation makes NO sense. It also seems to me that a smoothing algorithm on the Garmin data would give a very accurate elevation. Garmin should certainly do it with their training software and Garmin Connect. MMR should also do it to Garmin submissions since I don't see why it would be complicated at all to take the raw data from the Garmin, do a curve smoothing and then add the elevations. With patience I could do it using the Garmin training center cursor.

     Link to TFCE 100 miler in MMR:

     http://www.mapmyride.com/ride/united-states/ma/north-dartmouth/550125287161876743

     Garmin Connect upload of 70 miler:  http://connect.garmin.com/activity/13279615

  8.  
    stinsonddog

    I agree that this issue really limits my interest in the site.  The elevations are just way too far off to be acceptable.  I have documented 2400 feet climbs coming in at way less on MMR.

     

     

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