GPS vsMeasuring Wheel

I measure my foot. Then I walk the course putting one foot directly in front of the other. I count the steps it takes, then multiply the number of steps by 12 inches.

Try it.

GPS isn't accurate at all.

Iv'e used a Garmin for a while now and I have found it to be fairly accurate in relation to known distances. The wheel is far more accurate, but for training purposes, I think you would find it to be accurate enough, except in cases where satellite pick-up is not good. This does occur when buildings or other obstructions are a factor.

Why don't you just use www.usatf.org/routes

If you have a bicycle with a well calibrated odometer it works just as well as the wheel (which is a hell of a lot better than most GPS devices), but a lot easier.

Or, as the guy above said, you could use something like www.gmap-pedometer.com. This won't be quite as accurate as the bike, but will be pretty close and still a lot better than a GPS device, and obviously easier to do.

I have a Garmin Etrex that I use when I go on runs in unfamiliar places. It's nice to go on a 15 mile run at random and always know exactly where you are in relation to the starting point (or any other known latitude/longitude). On a road with no trees it gets good enough accuracy for training purposes...not as accurate as the bike measurement device, but it's good to 10-20 meters over 1 mile.

It's wooded around here and the average GPS is pretty inaccurate as far as distance if you have many turns (I have a Garmin bike mounted unit). I know a gal here who has one of the wrist mounted units that's say "oh that's short" when talking about area routes when I've measure those routes with a calibrated bike.

I like the GPS for documenting mile markers because it's an easy way to get someone to the ball park where they can see a more accurate landmark for placement.

My recommendation is find a good bike odometer, look on the USATF site for a calibration course in your area and calibrate your bike.

As far as my training runs I just guess based on how long I was out there and how fast I thought I was going. Most fo your training is just getting time on your feet anyway to what does it matter?

If I want a specific distance I either use the track or a half marathon course where I know all the markers.

Why the hell would you care whether a trail course was a tenth of a mile off? IT"S A TRAIL. There are hills, turns, mud, etc. (this also applies to any road that has hills). The time means NOTHING compared to other "accurate" trail or road segments.

If you want accuracy, find a track or flat road course. Otherwise just pick a "close enough" landmark and stick with that.

use google earth