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Garmin Connect Adds Extra Distance

Being somewhat of a stickler about recording my mileage, I always run to the full kilometer - i.e., I always trim off the extra couple of meters that are picked up as I come to a standstill. Suddenly it's happening that when I upload my run to Garmin Connect, my runs are always have an extra .1 or .2 tacked on the total distance of the run.

Just to be specific; if I plan to complete a 10 kilometer run, I'll press the stop button pretty much when I've just passed the tenth kilometer. And before I upload to Garmin Connect, I'll delete the final "lap" (I've got the auto lap feature set to 1 kilometer) which is usually a couple of meters.

However, even though the run data on the watch will indicate a perfect 10 kilometers (and once I've uploaded the run to Garmin Training Center - it will also indicate a perfect 10 kilometers) when I upload the date to Garmin Connect, the total distance will read as 10.1 or 10.2.

This has only started happening just over a week ago (February 7th to be exact). I had not changed any settings whatsoever. I've tried a full factory reset of the watch (Forerunner 305) - to no avail.

Anyone else experiencing this, or have any ideas to correct this?

0 Dugiflopper over 11 years ago

don't be such a stickler.... it's the trends in your overall training you need to be concerned with, not that it adds up and balances like financial statement.

Just my opinion.....

0 jpwgibson over 11 years ago

So, Coach Einstein, in other words, you haven't the insight to solve this technical matter.

There; was that so difficult?

0 The_Hunnymonster over 11 years ago

Read and understand http://earthmeasurement.com/GPS_accuracy.html or http://www.riverregionrunners.org/html/gps_accuracy_article.html and you'll be a long way to understanding why you could run the same course 10 times and get 10 different reported distances.

Add in the unknown of how the interpolation between data points is made (straight line? bicubic curve? polynomial curve?), is elevation change being accounted for? on the watch and on Garmin Connect and you can easily present the same data input (string of points in 3D space) and the line connecting them can easily vary by ±5%

0 jpwgibson over 11 years ago

Thanks for your thoughtful and productive response, Mchunnymonster.

I suspect that my question is why has this only begun to happen quite overnight, as it were? I've been running with this same watch for about 3 years now, and following the same modus operandi: I "trim" the final little bit of distance to tally up an even total distance.

So in the course of 3 years, running at least 3 times per week throughout those 3 years, and never once ever having had this issue of residual distance; why would it suddenly appear on every run since the issue began (February 7th)? How could it be that the technical points which you've mentioned have only come into effect as of February 7th? I've completed 6 runs since that date, and each of them has either .1 or .2 tacked on to the total mileage. Furthermore, why is this extra bit of distance showing up only on Garmin Connect, but not on Garmin Training Center, nor on the watch itself? Are the technical matters you've presented applicable only to Garmin Connect, and somehow leave Garmin Training Center and the watch unaffected?

0 The_Hunnymonster over 11 years ago

Well there was some downtime recently (I think it was 5th Feb?) No published changelog on what happened in that downtime, but its not beyond the realms of possibility that there has been some change in the parsing of the GPS data... Can you try uploading an activity created before Feb 1 (to be certain it was before the downtime) and see if that also gets extended?

Obviously TC wouldn't be affected because that hasn't been upgraded since the last ice age ;)

0 jpwgibson over 11 years ago

Thanks Mchunnymonster,

I think that is a very sound theory. Unfortunately I delete my activities pretty much immediately after uploading them, so I cannot re-upload any of these, alas.

As sound as your theory is, I do have another to consider. I believe that it could very well be that the U.S. aerospace agency has manipulated their satellites in some way in a bid to gain the upper hand over Canada in the upcoming Olympic gold medal hockey game in Sochi. This bit of tinkering has the added negative side effect of meddling with the equations in the training mileage of runners north of their border, in an effort, I suppose, to meddle with the aspirations of athletes in that sport as well.

0 Pyrianasa over 3 years ago in reply to jpwgibson

When I upload my running distance, Garmin adds .5 or .6 mile - that seems like a lot to add. This is as of September 2021. Just started doing it recently.

0 seilogramp over 3 years ago in reply to Pyrianasa

Are you saying the watch will show, for example 5 miles, but after uploading Garmin Connect says 5.5 miles? Could be a number of things. If you can zip and attach a fit file from one of these activities, we can have a look at the data before and after uploading to Garmin Connect.

0 Pyrianasa over 3 years ago in reply to seilogramp

Yes, exactly. So, for example, if I ran 3 miles as an Activity but also walked 2.4 miles, when I upload the data from my watch, my total shows on the website as 6.0 instead of 5.4.

0 seilogramp over 3 years ago in reply to Pyrianasa

seilogramp said:
If you can zip and attach a fit file from one of these activities, we can have a look at the data before and after uploading to Garmin Connect.

Was the walk not recorded as an activity? Was it based on Move IQ? So if you can attach your watch to a computer and copy, zip, then attach one of the .fit files from the \GARMIN\ACTIVITY folder, we can see what is going on.