… Race organizers know this problem all too well. Douglas Thurston, operations director for the Competitor Group, which organizes Rock ’n’ Roll Marathons, a series of races across the country, braces himself for complaints with every race.
Runners who wore GPS watches start e-mailing him or posting comments on Facebook or Twitter afterward. The course was measured incorrectly, they will say. According to their GPS devices, it was too short.
Mr. Thurston has gotten so used to the complaints that he actually has a generic e-mail reply. No, it says, the course was not wrong. Your GPS device was.
“If someone wants to go to mat on it, I ask them to go to a 400-meter track and run on the inside lane for 12.5 laps. That’s 5,000 meters,” he said in an interview. Then, he tells the runner, check the distance on your GPS device. He guarantees it will not be 5,000 meters.
all the examples they gave show the watch being short. And that’s not usually the case. Plus the example the RD uses of the track doesn’t jive with the reasons they give for it being off.
I still laugh when people post things on FB that say “my garmin said 13.4 miles, so my pace what X:XX not x:xx like the results say”
I’ve never once in all of my runs ever had my watch come up short on distance. Maybe I need to pick a better line, or just stop zig zagging all over the place to get around people.
His example on how to check gps is pretty dumb too given no one is running distance with gps on a track. If that many people are saying the course is short maybe he should go check it. They may not be perfect, but multiple people consistently saying something is wrong, I surely wouldn’t be so cocky. It also depends on how off they are saying it is. If its .1 off well that’s maybe actually off. But .5+ something is up.
I ran the Green Bay marathon in May with my Garmin 305 earlier this year and noticed that the mile markers were off by about 0.2 mi mid-race. I’m used to a variance of 0.1-0.2 in the total race distance, but this was odd. I could also hear the beeps on other people’s watches (for their lap alerts) well before the mile markers. Turns out the course was long and after enough people noticed, the RD investigated & took action: http://www.cellcomgreenbaymarathon.com/marathon/finish-times-to-be-adjusted
“If someone wants to go to mat on it, I ask them to go to a 400-meter track and run on the inside lane for 12.5 laps. That’s 5,000 meters,” he said in an interview. Then, he tells the runner, check the distance on your GPS device. He guarantees it will not be 5,000 meters.
Not a fair test as GPS devices will not be as accurate on a small track where the inherent inaccuracies associated with the GPS satellites is more exposed. On an open course the accuracy gets better but still unlikely to be spot on. However, to blandly dismiss input from all GPS devices as being inaccurate is a bit harsh Problems do exist with course measurement and the number of different GPS devices in use on a course registering inaccuracies could indicate a problem. It pays to keep an open mind.
ONE: you have just admitted that "gps devices will not be accurate on a small track where the inherent inaccuracies associated with GPS " Hence you admitt that they are inaccurate…are they just inaccurate for tracks and then they magically become accurate for longer distance. What if part of the run course is close to another part of the course so that it looks like a track oval. The Jones measuring wheel isn’t inaccurate when it it measures a track and then suddenly accurate when it measures a marathon course
TWO: Everyone’s GPS measures similaraly because …they all use the same satellites and technology. Hence the device is very reliable but inaccurate. Ask yourself this: which is likely to be more accurate, a jones counter (http://www.spikesmag.com/features/howtomeasureamarathoncourse.aspx) directly measuring distance on the course, or a device that relies on triangulating steallites hundreds of miles in the air, and then doing mathmatical computations to give you a distance
ONE: you have just admitted that "gps devices will not be accurate on a small track where the inherent inaccuracies associated with GPS " Hence you admitt that they are inaccurate…are they just inaccurate for tracks and then they magically become accurate for longer distance. What if part of the run course is close to another part of the course so that it looks like a track oval. The Jones measuring wheel isn’t inaccurate when it it measures a track and then suddenly accurate when it measures a marathon course
TWO: Everyone’s GPS measures similaraly because …they all use the same satellites and technology. Hence the device is very reliable but inaccurate. Ask yourself this: which is likely to be more accurate, a jones counter (http://www.spikesmag.com/...amarathoncourse.aspx) directly measuring distance on the course, or a device that relies on triangulating steallites hundreds of miles in the air, and then doing mathmatical computations to give you a distance
What do you mean, specifically when you say “inaccurate”?
The wheel is likely to be more accurate if properly calibrated, but I don’t see myself running with one.
Isn’t GPS tecnology inprecise to begin with. For instance, the original models would be off by 100 yards due to gov’t controls, but then were accurate to within 20 yards. I don’t know about current tech, but being off by 20 yards at any given point is bound to create a significant level of reading error when measuring distance, especially over a long one.
for one i was quoting what previous posters had written about how everones garmin beeped at different places and to cooresponding to the run markers…etc. So I’m not saying you should run with a jones counter. Run with a garmin. But don’t be a bit sruprised that it will be off at the end of the day. I run with one, but i don’t for won second think that the RD’s put on a bogus race because my garmin says so. It is well known that they are inaccurate. 1-5% but the poster i responded to stated they were inaccurate
All I’m saying is that they give you a rough ideas of distance pace etc. but they are not as accurate as the jones counter and if a race has alot of turns you will end up running longer
ONE: you have just admitted that "gps devices will not be accurate on a small track where the inherent inaccuracies associated with GPS " Hence you admitt that they are inaccurate…are they just inaccurate for tracks and then they magically become accurate for longer distance. What if part of the run course is close to another part of the course so that it looks like a track oval. The Jones measuring wheel isn’t inaccurate when it it measures a track and then suddenly accurate when it measures a marathon course
TWO: Everyone’s GPS measures similaraly because …they all use the same satellites and technology. Hence the device is very reliable but inaccurate. Ask yourself this: which is likely to be more accurate, a jones counter (http://www.spikesmag.com/...amarathoncourse.aspx) directly measuring distance on the course, or a device that relies on triangulating steallites hundreds of miles in the air, and then doing mathmatical computations to give you a distance
Less accurate due to tight bends so overall accuracy will increase on a course with fewer bends. But, as we all know, there are many factors that affect the accuracy of a Garmin. So, probably fairer to say they are likely to be less inaccurate over longer more open courses.
While everyone’s GPS might measure similarly, does not mean they will all produce the same results - can we say they are reliably inaccurate then?
Any calibrated and certified measuring device will produce an accurate reading of the one line on the course that equates to the exact distance ±42m. I agree it is unlikely to be a GPS device, but I still say that if a large number of GPS devices indicate wide deviation from the published distance there may be a mistake in the measurement.
All I’m saying is that they give you a rough ideas of distance pace etc. but they are not as accurate as the jones counter and if a race has alot of turns you will end up running longer
I’d say GPS give you a lot better than “rough ideas”, but agree that a GPS isn’t as accurate as the wheel. That said, if everyone in the race ran with a wheel I bet they’d be clicking over mile marks in different places too.
He is correct about the inside lane 1 being short. The far outside lane 8 will be long. Lane 4 of an 8 lane track will be accurate to the 5000 meters he is referencing.
The inside of Lane 1 is 400m. Every lane to the outside is longer.
If you are assuming lane 4 is 400m because it’s in the middle of an 8 lane track than it would actually be the outside of lane 4 and the inside of lane 5 (hence both if you can run anywhere in your lane). That notwithstanding it’s the inside line of the first lane. That’s why the other lanes get a staggered start in a 400m race where they have to hold their own lane.
Gps is a close, guide of measure. It’s like using a ruler when you need a set of calipers to measure 1/1000 of an inch.
They are convenient, but lack precise measure. When a gps measures more than my bike computer, I joke and tell friends I turn more efficient than them and I shave off distance. They look puzzled and believe me. Haha
My experience with my Garmin 405 has been excellent. It is reliable, doesn’t drop signal and is sufficiently precise and accurate. I routinely run a ~4 km loop course and my GPS measurement is at worst 30 m off.
That said, my buddy owned a 405 that used to routinely drop signal, which made it almost worthless.
That’s why we have foot pods also. That can be dialed in at any track or measured road :0) great for them times you are running and cannot get a signal…just saying.