Average and Max speed differs from Strava

[Danfro]

Originally reported by @kugiigi under ernesst#16.

Steps to Reproduce

Extract a gpx file from Strava
Import the gpx file to Activity Tracker
Compare the speed data between Strava and Activity Tracker

Expected Results

The speed data are the same or at least close
Actual Results

The speed data differs by a considerable margin.

Additional Notes

This needs further test though since I haven't tested thoroughly.

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Here's a screenshot from Strava

And from Activity Tracker with the same GPX file.

Here's the actual GPX file:
Morning_Ride.gpx.zip

Additional Info:
Sometimes I also see some failed/broken gpx files where the max speed is lower than the average speed so obviously something's wrong. This happens when my location jumps from place to place or it stops working at some point.

[Danfro]

@1896er reported:

Hello, I also see different values for the same gpx file. In the example the file was created with activitytracker. The top speed always seemed too low to me in the ad. I imported the example file into "Komoot" once: top speed with "Komoot" 30.4 km / h - with activitytracker 26 km / h.
Attached are screenshots from "Komoot" ("Geschwindigkeitsprofil") and activitytracker. Also the gpx file.
Volla Phone, ota -18.

By the way: The average speed is displayed almost the same (Komoot 19.3 km / h, activitytracker 20 km / h). But actually it should be identical, right?

Many greetings
Florian

1635260603.zip