The Power data is available for the whole run if I look at the session in Polar Flow and it at least seems accurate as well.
I realized one can import a TCX file on Golden Cheetah as well, so I tried exporting one from Polar Flow and importing it there. The TCX file for the Aug 7 run (the one whose FIT file I sent you) is not missing any Power data or GPS data. Would this suggest there’s something off at the conversion stage or is this Polar trying to fill in the blanks? I’m trying to wrap my head around what is closest to the actual raw data.
The HR, and the Power data (when present) seems to match between the files but the GPS data is a little bit different (for example 62.23267833 vs 62.232429442). I don’t know if this discrepancy in the GPS data is anyhow meaningful.
I’m getting more and more convinced that there is a problem with the FIT files coming from Polar. Polar only started a year or three ago to make the FIT files available through an API. I’m not a Polar user so I don’t know if they have a FIT download available from the Flow app. As far as I am able to find out, the Flow app only gives access to TCX, CSV and GPX. And the devices only support TCX. Meaning that there is some conversion going on at the Polar site to output FIT.
Intervals get’s the FIT from the Polar API. Don’t know which one Strava gets.
What is the data looking like in Intervals when you manually upload the TCX there? Just go to the Activities page, click on Upload and point to your downloaded TCX file. If that looks correct, there must be a problem at the Polar site. But that would be strange since nobody else is reporting problems
The speeds are fine as well. Also, interestingly enough, the Load is the exact same, so I do wonder how we get the same Load with two very different sets of data.
You’re right that Polar doesn’t allow exporting to FIT. I’m also not sure how exactly it’s done with Intervals. At least for the old activities Intervals asks you to submit the download link you can get from your Polar account when you request all data. This data is JSON files, not FIT, so I don’t know if Intervals then converts it somehow or somewhere or if it uses this data to ask Polar to sync the old activities, which it then might do by converting to FIT? I obviously have no clue about the technicalities here, but it is indeed beginning to look like the problem is in the conversion. But I’m also quite surprised this hasn’t come up earlier and/or more often.
Ok, so this probably explains it indeed. The “import all Polar data” option is actually there, and is the one that I used, so this explains the messed up speed data. If the problem doesn’t apply to new data, I think I’ll simply continue using Intervals “on the side” and then switch fully here perhaps for next summer.
I’m about to do an actually somewhat planned winter training this year for the first time ever, so I kind of need to be able to use old data for that That should also be plenty of time to get me enough NEW data so that I don’t need the other apps anymore when the summer season begins.
I thank you very much for all your help and for your patience!
Tx @MedTechCD for helping so much with this issue.
Intervals.icu converts the JSON files from the Polar import into FIT files and imports those. I had a look at your 1st August run and the velocity data is definitely off. Thats why the load is crazy when pace load is used.
The automatic sync does get fit files from Polar so there shouldn’t be an issue with those.
If you could get a TCX for 1st August and mail that to david@intervals.icu then I can compare. Tx.
I had a look at my code for this and there is a note:
/* speed data is way off so don't use it */
The speed is calculated from the GPS data. So thats why the import isn’t great. However I did introduce a little smoothing which makes it much closer to the TCX and also fixed a bug that was breaking power import (sometimes).
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