01-27-2007, 08:10 PM
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#10 (permalink)
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| Guest | Re: Trail lengths
Shawn wrote:
> Michael Halliwell wrote:
>
>> Micheal Artindale wrote:
>>
>>> I find more often than not, it is exagerated high, ie, 20km being
>>> less than 19km.
>>>
>>> It is rather annoying.
>>>
>>> Micheal
>>>
>>> "Coyoteboy" <coyoteboyspuduk@hotmail.com> wrote in message
>>> news:8eSdnTA4C_cscyXYnZ2dnUVZ8s7inZ2d@bt.com...
>>>
>>>
>>>> Ive noticed that on a lot of rides here in the UK the trail builders
>>>> claim "20.4Km" or such like but when i take my GPS out, even with
>>>> continuous tracking and taking height gain into it I can still come up
>>>> several Km short of the stated distance. Does anyone else find
>>>> this?
>>>
>>>
>>>
>>>
>>
>> Depends on how they measure it. AFAIK, GPS usually records a
>> horizontal distance whereas bike computers include the lengths of the
>> inclines. Usually means that the GPS will give a lower value as
>> compared to a bike computer. The more hills on the trail, the worse
>> this can be. On the flip side, a lot of GPS units also tell you the
>> vertical distance covered to make up for it 
>
>
> Do the trig to figure out how much that difference is for a ridable
> trail. It ain't much.
>
> Shawn
True, but it accounts for some of it Of course, trails can also be
transient...section goes bad and it gets bypassed, impacting the trail
length which may not be reflected in what the builders claim. Or it
could be as simple as the initial measurement being off....someone
forgets to reset their computer or uses an air photo to pull off
distances or any number of things. Personally, I use the claimed
distance as a rough ballpark at the best of times.
Michael Halliwell
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