The old version of the gpx spec is the only one I could find that explicitly mentions speed.
From this, I think the gpx export should always use meters per second, even when the user has configured miles per hour for the gui. However, I have no other gpx program to explicitly compare against.
From http://www.topografix.com/gpx_
====
Units: meters per second
====
SportsTracker outputs mph when internal (gui) settings are set to mph.
Example output:
0.0
18.2
207.5
Speed 18.2 mph Distance 7.13 mi
2009-04-19T13:26:22.28
2844
Whereas I'd expect:
0.0
13.05
207.5
Speed 18.2 mph Distance 7.13 mi
2009-04-19T13:26:22.28
2844
i.e., with speed converted to m/s from mph, but possibly still described as mph in the description.
When the gui setting was set to km/h (on a different capture), the speed appeared to also be output as km/h not m/s. I couldn't determine any tag that would indicate "mph" or "kmh" was being used rather than m/s which is why I think it is a bug.
I don't know if there is a similar units problem with the elevation field.
I noticed that "viking" also couldn't correctly parse the time fields due to no "Z" timezone indicator. However, I think this is a bug in viking. But, perhaps we could always add the Z since we know timezone?
This is with latest sportstracker version v2.06.
Thanks.