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Mapping Sites, Total Ascent & Tour of the Black Mts.

cakewalkcakewalk Posts: 220
The Tour of the Black Mountains Website reports 3,793 metres.

Bikely ( ... tains-2007) gives 2,924 metres.

So I copied the data from Bikely to mapmyride (GPX file) : ... /793795287 . This gives 1,760 Metres!

I then downloaded the data from mapmyride into CSV file hand calculated the ascent and decent from the elevation figures. This came out at 2,312 metres.

I’m guessing mapmyride is a tad off! However does anyone have any ideas as to why these figures vary so much? Which one is closest to being correct? Should I stop using these sites and get an altimeter watch?
"I thought of it while riding my bicycle."


  • GeorgeShawGeorgeShaw Posts: 764
    The data will on the number of data points and whether any smoothing or rounding algorithm is added.

    You can see the same effect if you download a recorded GPX file from a Garmin for example) into different applications. Because of recording errors (vertical position cannot be as accurately measured as horizontal) then you can be measured as going up and down even on a flat road.
  • kmahonykmahony Posts: 380
    In my experience, the altitude from Bikely + 10% is usually fairly close.
    Some of the other mapping sites seem quite random.
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