No more marathons
I have a regular noon time run that Garmin usually reports as 4.75 to 4.8 miles.
On Monday I decided to add a bit to the run to bring it up to 5 - and the Garmin reported distance was 5.06.
On Tuesday I ran the same route, but about a half mile in I noticed that my pace and distance were off - problem with the initial acquiring of satellites - (You can see the problem if you view the maps in my log) so I clicked the lap button at where I normally hit 1 mile (garmin was reading .85) and when I logged the run I simply added the additional .15 to bring the run up to 5.
But that got me to wondering if either of the runs were accurate. So I decided to track the routes using the mapping function in RA. I decided to map the shorter route since that was the one I've run the most this past year. RA mapping put what garmin had been recording as 4.75 to 4.8 at 5.03. To further check it out, I used the mapping function in Map My Run and got 5.0.
Now, I understand that any GPS watch has a degree of inaccuracy (both plus and minus) but to consistently be SHORT by 4 to 6% seems to indicate a problem with my particular watch (Garmin 210 - about 2 years old).
Three questions for the B&B wise sages:
1. How accurate are RA mapping and MapMyRun?
2. Anyone experience anything like this?
3. Anyway to reset or re calibrate the Garmin 210.
Boston 2014 - a 33 year journey
Lordy, I hope there are tapes.
He's a leaker!
I'm not all that sage, and the smell of it in sausage sometimes makes me ill, but I believe map my run uses the street for measuring. Therefore it is likely to be the least accurate.
Your maps don't show. I assume you have the 'make maps public' turned off. Do you have a lot of turns in your route?
I don't run the exact same route very often, so don't know how closely the Garmin relates to actual distance compared to the others. It's pretty close and pretty consistent though. (I have the FR15.) I know there is a big difference in the way the three programs do elevation. When I pre-map a route before I run, RA will show significantly more elevation gain than the other two. Mapmyrun generally shows the least elevation gain. The Garmin elevation changes from day to day when I run the same sections, so I don't trust it completely. The first mile out of my house is sometimes 110', sometimes 130' up, sometimes something in the middle. RA lists it as 150'.
I can see the maps from here. Looks like a fairly well-developed area (lots of buildings to block the GPS signal) plus lots of turns. I would think it's the route rather than the watch. I bet the "measure route" function of RA would give you the most accurate distance for that route.
From the Internet.
MMR isn't that far off from RA for me - I had an annoying GPS experience on Monday, my dumb watch couldn't handle some of the turns and buildings near work, so I mapped it out and took that over the distance my watch gave me (6 miles with some obvious cut turns on the map from Garmin and a really slow last mile split for the effort, versus 6.22 from MMR and 6.19 from RA).
I'm also running with a 210, mine is 3 years old now and I've been wondering lately if an upgrade will be noticeably more accurate or if it'll still be somewhat limited in certain areas.
Interesting. Just mapped my usual route with the RA mapping and it matches my TomTom GPS and my older Garmins for the same route except by 0.02. Which is almost accurate, IMO.
I have found that with the Garmin, you might get days where the measurements were not the same. I always thought it was a glitch or not hooking to the satellites well.
Damaris
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Zelanie - I think you hit it. Not so much the buildings (they are all fairly low) but the number of turns. This particular route has 47 90 degree turns, and several more gradual turns. The Garmin would tend to smooth many of those, and cut tangents that aren't there..
I just remembered that I had worn my old Garmin 205 also on Monday (the 210 battery was low and I didn't want to lose the info - I know, I know - supper geeky) and it had nearly the same reading as the 210. So I'm guessing there's nothing wrong with the watch(s), it's just this particular course that confounds the GPS.