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Running Speed varies from Intervals to By Time
Describe the bug While watching the Data from a previous run, I noticed that the speed shown on the "Intervals" tab doesn't match the graphics shown on "By Time" and "By Distance".
To Reproduce
- Record a Run
- Click on the saved track
- switch to intervals tab
- switch to by time tab and compare
Screenshots
While the speed by interval is displayed as ~10 km/h the graphic shows speeds around 9km/h.
Technical information
- Device: LG G6 (H870)
- OS: LineageOS 17.1
- Version v3.12.0
Thanks for your nice Work. If I simply missed something please let me know.
Yes you are right - the computation is done in a different manner.
The interval is based upon distance / time: https://github.com/OpenTracksApp/OpenTracks/blob/679c1d7e3e326ec0400b850e291373d6c7612301/src/main/java/de/dennisguse/opentracks/viewmodels/IntervalStatistics.java#L117
The diagrams use the TrackStatisticsUpdater to recompute the TrackStatistics (the data shown on the first tab) and here a smoothing is applied: https://github.com/OpenTracksApp/OpenTracks/blob/0d493c410e31fffb1e39be210d254c4aa3c2a98f/src/main/java/de/dennisguse/opentracks/stats/TrackStatisticsUpdater.java#L51
So, the diagram is more like the data was that shown while recording and the interval tab is more "raw".
A related issue is: https://github.com/OpenTracksApp/OpenTracks/issues/213
Thanks @dennisguse
Maybe a solution would be to increase the GPS accuracy and turn of the smoothing. In my case, I manually calculated the average speed to be 9.75. This would be below the "Intervall" but above the "By Time" value.
I'm going to test a higher GPS accuracy setting tomorrow and will report back. I know it's more complicated than this, not everyone has the same phone. Maybe this information is valuable anyway.
We handle GPS accuracy by just ignoring every GPS fix that is above the set limit. So, we store less data and this can be beneficial or not.