[pct-l] GPS, distance and speed.

[steve_pct at hotmail.com (Steve Setzer)]

The other problem is that GPS may not take into account the vertical 
component of your route. For example, if you travel a mile in the horizontal 
plane, but also climb a mile vertically while doing so (I know that would be 
really steep) your actual distance travelled is 1.4 miles (the equation for 
the hypotenuse of a triangle) while the GPS may report your distance as a 
mile (just using the lat/long coordinates).

I know that my GPS - the Garmin Geko 201 - consistantly under-reports 
mileage when I'm on steep, switchbacking terrain but is right on for 
straight, flat trails.  I'm not sure if its becuase of the vertical distance 
or the reason that Dude mentioned in his emails.  Maybe both.  You could 
probably find this info from the GPS company.

Steve


>The short answer is "yes".  However, I would caution against relying on
>any GPS for pace and distance because the way that they calculate both
>makes them inherantly inaccurate.  The GPS is not in constant

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