Chimpware, out of interest do you have GLONASS enabled or just GPS? I've had it switched off but really disappointed with the tracks I've got. I've also got 1 second recording enabled
Here's my GPS comparison contribution for the day. Considering I'm comparing the fenix 5 to the Ambit3 Peak, and in my GPS torture testing grounds, I'd say it's pretty decent.
I did a run in the Amsterdam forest this morning wearing Fenix 5 and Forerunner 235.
Forerunner 235 gives a total distance of 13.61 km in Garmin Connect (the heart rate is off in this file; i had a problem with the strap) Fenix 5 gives a total distance of 13.34km in Garmin Connect
It's not clear to me which one is more accurate (both watches had GPS&GLONASS enabled and a garmin footpod connected)
Uploaded to mygps files they give 13.75km and 13.79km as total distance -----> Why does mypgs files give a different distance then garmin connect ?
MyGPSFiles uses their own algorithm to interpolate between the GPS data points and calculate the distance. It can sometimes result in different distances than Garmin Connect calculates. You can think of it as using a different type of best fit curve to fit a set of data points and then calculating the length of the curve through the data; if I use a line formula I get one length and if I use a polynomial I get a different length.
In the case of your data I suspect something more is going on with the fenix 5 that is causing it to under accrue data (I think 235 distance is more accurate and this is why); there are a lot of dropouts in your stride length, VO and GCT data. What are you using to collect this data an HRM-Run? This is similar to the behavior I have seen when the Stryd data drops off it affects the distance accumulation on the fenix 5.
The only way to know the exact distance you ran is to plot it yourself on the exact course you ran using any online tool and turn off "Follow "road" and click exactly where you ran. This will give the exact distance and you can compare it to the calculated distances. I have done this many times in the past and the Garmin Connect distance has always been very accurate when the data is decent (i.e. the track from the watch is relatively good with few diversions).
What are you using to collect this data an HRM-Run? This is similar to the behavior I have seen when the Stryd data drops off it affects the distance accumulation on the fenix 5.
Thanks for the clear explanation ! I'm using an HRM-tri which indeed seems to have been disconnecting quite some times; a garmin footpod was also connect to the fenix 5. The forerunner 235 was connected to a wahoo tickr run chest strap; but that one fell off during the run.
Something odd is also happening with the calorie calculation; 589 according to FR235 & 920 according to Fenix 5. I believe the rule of thumb is approx 70 per km; so +/- 900 seems to be more accurate.
So it seems that when the fenix 5 has disconnects from external data streams it affects the distance accrual algorithm. It is most obvious with the Stryd, where even if I use the Stryd for Pace only and not distance and the data drops out the distance accrual is off.
Regarding the calorie calculation, yes I would agree the fenix 5 calculation seems more accurate. That clearly seems to be caused by bad HR data on the 235 (you can see in the middle of your run and in some other spots where your HR drops down to highs 80s to 90s and this is not consistent with the run or the data from the f5). So I would blame the poor HR data on the 235 for the miscalculation.
It's a pity; I got the hrm tri because the ohrm of fenix5 was not working well for me; but if the strap disconnects for whatever reason that solution is also not working :(
