Garmin versus Disney Distances

[GeorgeAndDiana]

Kind of an odd question, but I'm sure there are many folks on here that are in the know.

I have a Garmin 305. I love it, think it's one of the best investments I've made for training. Of course, being a GPS, it's got some inaccuracies. I ran a local (Columbus, OH) 10K and pushed "Start" at the start line as I crossed. I noticed that I reached the 10K point on my watch just a little bit earlier than the finish line, though, maybe about 0.2 miles. Of course, many factors can go into that, including the folks running the local race having a slightly inaccurate distance.

My question is this: For those of you who have run the runDisney events at WDW, and have a Garmin, what has your experience been? Do you generally cross the line at 13.10 miles? A little before? A little after? I'm just looking to get a feel for what to expect, if that makes any sense.

Take care, everyone, and best wishes for your training!
George

 

[SAHDad]

Actually, you should never have a Disney race end at 3.1, 13.1 or 26.2 miles, for a variety of reasons.

First, all races are (or at least, should be) measured on the tangent. That means that they measure along the inside of each corner, cutting as tightly as possible, and then making a line, as straight as possible, for the next corner, even if it is a mile away. It's pretty much impossible to run a perfect tangent on the course, but this prevents anyone from actually cutting the distance. (Or, put another way - take the inside corners as much as possible - you won't make the race shorter, but you prevent it from being longer.)

Second, the course is not measured with all sorts of other runners and spectators around. You might not think a quick jog around the people in front of you, or a brief dash over for water or a porta would matter, but those things add up.

Third, all road courses are supposed to have an overage factor (IIRC, it is .1%, or .026 miles for a marathon). This is to prevent a course from accidentally being short.

It doesn't always work - a local "10k" course is actually only 6 miles long, which made my PR there a little annoying.

Anyway, I think the half has come in about 13.4 for me, give or take, and the full about 26.5, which is in line with other races of similar distance.

 

[johde]

I haven't run any of the runDisney events at WDW, but I have done 4 half marathons including the Disneyland Half in Anaheim. In every one of them, I've run over 13.1 miles according to my Garmin. The problem you have is 2 fold. You've hit on the first one. GPS has a small degree of inaccuracy. If you download the data and look at in on the computer you will see it stray off course as you run. The second problem is the course is measured using the absolute shortest path possible, cutting all of the corners perfectly. In real life, you weave in and out of traffic, take some corners wide, etc. That all adds distance to your run. I would figure running a couple of extra tenths of a mile based on what your Garmin says. Here's my Garmin results from Disneyland to give you an idea. My starting and stopping was real close to the the start and finish line.

 

[FireDancer]

In addition to the tangent factor races in large cities can also cause problems with the GPS. I haven't had any problems in most cities but for the Pittsburgh half we start downtown and run through downtown with about 1 to go. Both times the watch couldn't fine the satellite which caused it to skip and tell me I was running a 4:00/mile pace at mile 1 and 12. I assure you I was not. It has to do with where in the sky the satellites are and if the buildings interfere.

Even when buildings aren't an issue sometimes the watch just has a "senior moment". I don't live near anything that would constitute a tall building and run from my house all the time. Over the course of a year about 2 or 3 times the watch will not pick up the satellite right away or lose it for a couple hundred meters at the beginning of my run. I wait for the watch to indicate it has found the satellite and is ready, I hit start, it even starts but when I finish and upload the data it tells me I started half way down the street. I have no idea why but it is a computer and as an IT director I can assure you computers don't always behave predictably.

 

[paxsarah]

I love this DC Rainmaker explanation of why you'll pretty much always see a longer distance on your Garmin than the race is supposed to be.

 

[ironz]

For the reasons discussed above (sampling, tangents, etc)...Garmins are not going to be 100% accurate.

Disney races are USATF certified...you can see them here:
http://www.usatf.org/events/courses...me=&queryType=basic&format=view&submit=Search

(and that link is going to be shortened...so click it, don't try to cut and paste).

 

[Qltrgrl2]

My Garmin showed 13.2 at the Disneyland Half marathon in September. I was very careful while running and because I was not around a bunch of people after the start, I managed to hit lots of curves correctly. My goal was a PR, despite the rather warm temperature, and it happened so I was very happy!
Happy Running!
Pam

 

[DisneyRunnerGirl]

Kind of an odd question, but I'm sure there are many folks on here that are in the know.

I have a Garmin 305. I love it, think it's one of the best investments I've made for training. Of course, being a GPS, it's got some inaccuracies. I ran a local (Columbus, OH) 10K and pushed "Start" at the start line as I crossed. I noticed that I reached the 10K point on my watch just a little bit earlier than the finish line, though, maybe about 0.2 miles. Of course, many factors can go into that, including the folks running the local race having a slightly inaccurate distance.

My question is this: For those of you who have run the runDisney events at WDW, and have a Garmin, what has your experience been? Do you generally cross the line at 13.10 miles? A little before? A little after? I'm just looking to get a feel for what to expect, if that makes any sense.

Take care, everyone, and best wishes for your training!
George

George - I too am from Columbus (Worthington) and use a Garmin. Would you mind telling me which 10k you ran - I'd love to see if I ran the same one and how close my Garmin tracking was to yours. Just for kicks and giggles...

 

[GeorgeAndDiana]

George - I too am from Columbus (Worthington) and use a Garmin. Would you mind telling me which 10k you ran - I'd love to see if I ran the same one and how close my Garmin tracking was to yours. Just for kicks and giggles...

Small world! I ran the Wellness in the Woods 10K on September 18th, starting right there in Worthington. Nice to meet you!

 

[GeorgeAndDiana]

Actually, you should never have a Disney race end at 3.1, 13.1 or 26.2 miles, for a variety of reasons.

First, all races are (or at least, should be) measured on the tangent. That means that they measure along the inside of each corner, cutting as tightly as possible, and then making a line, as straight as possible, for the next corner, even if it is a mile away. It's pretty much impossible to run a perfect tangent on the course, but this prevents anyone from actually cutting the distance. (Or, put another way - take the inside corners as much as possible - you won't make the race shorter, but you prevent it from being longer.)

Second, the course is not measured with all sorts of other runners and spectators around. You might not think a quick jog around the people in front of you, or a brief dash over for water or a porta would matter, but those things add up.

Third, all road courses are supposed to have an overage factor (IIRC, it is .1%, or .026 miles for a marathon). This is to prevent a course from accidentally being short.

It doesn't always work - a local "10k" course is actually only 6 miles long, which made my PR there a little annoying.

Anyway, I think the half has come in about 13.4 for me, give or take, and the full about 26.5, which is in line with other races of similar distance.

Thanks for your input! I guess I find myself counting down to my target distances, partially because I'm just like that, and partially because it's my first half I'm training for, so it's good to know what to expect. Makes sense on the distance being a bit higher, I guess I was just a little surprised in Columbus because our 10k path was pretty much a big straight line and back.

Was your half number at WDW? I ask because I think there are less buildings on that path than say, at Disneyland/Anaheim.

George

 

[jbucci]

For all of the reasons everyone gave, my Garmin tends to think I'm done before I actually am finished. My Garmin is generally "off" by around .2 to .3 miles by the end of a race even when I make an effort to run the tangents and try not to weave.

The one good thing about a Disney race is most of us are pretty familiar with Disney so by the time you reach Epcot you kind of know how far it is to run to World Showcase and back so you can use that as part of your mental guide as well. By the end of the race there are usually crowds and cheering people to make you not care as much about the "extra" distance you have to run.

 

[SAHDad]

Thanks for your input! I guess I find myself counting down to my target distances, partially because I'm just like that, and partially because it's my first half I'm training for, so it's good to know what to expect. Makes sense on the distance being a bit higher, I guess I was just a little surprised in Columbus because our 10k path was pretty much a big straight line and back.

Was your half number at WDW? I ask because I think there are less buildings on that path than say, at Disneyland/Anaheim.

George

I'll have to see if I can find it - one of my log books only goes back about 4 years, so it might miss it by a couple of months. (Switched computers about that point, and not all of the old data got transferred.)

I do recall that the half was pretty close - there weren't anything that caused the Garmin to drop signal or anything. The full did have a section in DHS (the costuming area of the backlot tour, I think) where the Garmin just gave up for a minute (since you went through a longish tunnel), but an overpass or Cinderellas castle doesn't typically pose a problem.

 

[GeorgeAndDiana]

For all of the reasons everyone gave, my Garmin tends to think I'm done before I actually am finished. My Garmin is generally "off" by around .2 to .3 miles by the end of a race even when I make an effort to run the tangents and try not to weave.

The one good thing about a Disney race is most of us are pretty familiar with Disney so by the time you reach Epcot you kind of know how far it is to run to World Showcase and back so you can use that as part of your mental guide as well. By the end of the race there are usually crowds and cheering people to make you not care as much about the "extra" distance you have to run.

Good point about the Disney familiarity, Jen. As we know we're pretty well acquainted with the in park distances. There were also no crowds in our little local race, except for the last 0.1 miles or so, so that will definitely be a slight environmental shock

Is it time for the race yet? I can't wait!

 

[megny]

For the W&D half, my garmin registered 13.4, I believe.... yet another reason to train for faster than the minimum pace... I didn't consider this before...

 

[FireDancer]

Out of curiosity I checked what my Garmin registered for the full in January of this year along with the Wine & Dine half from last year. The full came in at 26.44 and the W&D came in at 13.19.