an update to course length info

I just stumbled across this great article that explains how courses are measured as well as how Garmins work to explain how our Garmins can come up with a long measurement when we are working our butts off on a marathon: http://www.hamptonrockfest.com/hamptonhalf-GPS.html

Turns out, my original information about how much long a course has to be certified by was off by a decimal point...or two.  The course must be 1/10th of 1% long, so really, not too much long at all.  (Sorry about that! I thought I had it on good authority...)

But where the big difference comes in is how the Garmin measures distance.  Those giant arm boxes aren't tracking us down to the second.  Nope, the device is plotting points every few seconds, and then it connects the dots.  Not only that, the Garmin only guarantees accuracy within 10 meters on average.  Throw in all of the other factors that can interfere with signal, and you've got a device that isn't nearly as accurate as the methods they use to measure a course.

If you want the nitty gritty details, be sure to check out the article.

Which means, sniff sniff, that I really ran slower at the Seattle Rock n' Roll marathon. Crap!