Boston Garmin measurement

Here is how a garmin works: a satellite in outer space plots signals from a GPS device on your wrist. Sometimes the satellite comes up short, sometimes the satellite is a little long, sometimes the satellite doesn't connect when you are under trees or between tall buildings and makes a best guess. IT IS NOT 100% ACCURATE. NEVER HAS BEEN. GROW UP. JUST BECAUSE YOU ARE WILLING TO PAY $400 FOR IT DOESN'T MEAN THAT IT IS 100% ACCURATE.

And the tangents on the course can easily eat up .1-.2 mi over the entire course.

Precius Roy wrote:

Here is how a garmin works: a satellite in outer space plots signals from a GPS device on your wrist. Sometimes the satellite comes up short, sometimes the satellite is a little long, sometimes the satellite doesn't connect when you are under trees or between tall buildings and makes a best guess. IT IS NOT 100% ACCURATE. NEVER HAS BEEN. GROW UP. JUST BECAUSE YOU ARE WILLING TO PAY $400 FOR IT DOESN'T MEAN THAT IT IS 100% ACCURATE.

And the tangents on the course can easily eat up .1-.2 mi over the entire course.

I think most of us are not saying its accurate. Why don't you grow up and take of the caps....

It just an interesting set of data to see and compare.

I still find it amazing I can put on a small wristwatch, hit start and stop and have it measure 26.36 miles on a course that is 26.22 miles (0.53% error or 99.47% accuracy). I still think that's pretty good.

nikeman wrote:I started my Garmin as I crossed the start line and my chip time was exactly the same as what was on my Garmin. It read 26.56 miles. Another friend's Garmin read 26.61 miles. Since there really aren't THAT many tangents to cut, it would make sense that the course is a bit long ?

Anyone else wear a Garmin or GPS and get a similar reading ?

There was likely a lot of incoherent stumbling in the later miles.

Keith Stone wrote:

nikeman wrote:I started my Garmin as I crossed the start line and my chip time was exactly the same as what was on my Garmin. It read 26.56 miles. Another friend's Garmin read 26.61 miles. Since there really aren't THAT many tangents to cut, it would make sense that the course is a bit long ?

Anyone else wear a Garmin or GPS and get a similar reading ?

There was likely a lot of incoherent stumbling in the later miles.

LMAO!!!Absolutely...FYI I had 26.51 and I started my Garmin from the corral I was in..I ran the tangents poorly...

I only paid $127 for my Garmin.

Keeps my from going out too fast the first lap in my races.

Vin wrote:

A garmin, or any other GPS based measuring device, is not 100% accurate. The GPS does not following your each and every movement, and therefore isn't as accurate as the wheel that is used to measure the USATF certified courses.

For more information on the measuring procedure and explanations, visit the usatf site,

http://www.usatf.org/events/courses/certification/manual/

So if it's a USATF certified course it's elligible for the American Record, right?

here we go again!

The course is long. All road courses are long. They have to be to be USATF certified.

Another wrote:

Is the an online map or Google Earth map of the Boston Marathon and where exactly all of the marathon mile markers are? It would be interesting to overlay that with my race and to see how the distance grew as I ran.

Also, I'm sure as we got into downtown Boston the error of the Garmin would increase as building get taller etc.

Garmins are basically useless in big city marathons like New York and Chicago.

I Googled it for you ;)

Hopefully tRg will leave you for starting this thread!

Embarrassingly, the course map I provided the link to appears to have been done with a Garmin.

So I tried the Boston Marathon site instead

http://raceday.baa.org/course-maps.html

Randy Oldman wrote:

Embarrassingly, the course map I provided the link to appears to have been done with a Garmin.

So I tried the Boston Marathon site instead

http://raceday.baa.org/course-maps.html

That doesn't really help...

The first link was a little better.

I guess I could use this...

MA05018RN on usatf.org, but thats no fun...

Maybe it was the tailwind that threw off the GPS readings :>

d x 3 wrote:

Douche handle, douche girlfriend, douche post.

damn

Precious got ripped off wrote:

I only paid $127 for my Garmin.

Keeps my from going out too fast the first lap in my races.

Are you kidding? I really hope you're talking about track races on a regular track. Aw, that'd be swell.

No Way wrote:

The course is long. All road courses are long. They have to be to be USATF certified.

YES. and you have to run them in exact tangent lines to get close to 26.3 or 26.4 miles

Another wrote:

What amazes me, even at the faster paces, how lemming like runners are. They either just follow the person in front of them or just run down the center of the road. I had to tell people to run the feckin tangent a couple of times....

I normally stick the center of the road because it is the least cambered. I'll give up a couple seconds in using the tangents in order to decrease the chance of having a problem later in the marathon from running on a slanted road for the entire distance.

Another wrote:It would be interesting to overlay that with my race and to see how the distance grew as I ran.