The Vagaries of GPS Logging Sites

[Hacienda71]

I log my rides recorded on my Garmin on Endomondo and Strava. However they regularly deviate from the Garmin data and give me two different figures. I rode home at lunch today and these are the two sites interpretation of the same Garmin data.

Question does anyone know the reason why they differ and which site is more accurate?
http://www.endomondo.com/workouts/276034001/370856
http://app.strava.com/activities/99545332

Why are there different moving times different average speeds and distances despite both being given identical gps data?

 

[ColinJ]

'Access denied' on Endomondo!

 

[Hacienda71]

Should work now.

 

[zizou]

strava usually gives me lower average speed than what i get for the same data on garmin connect, i think it is related to auto pause particularly if you happen to stop on a segment.

 

[Supersuperleeds]

Strava always gives me lower average speed and steals so much elevation off me it is not funny.

 

[Crackle]

They all have different 'engines' to interpret pauses, stops, gps track correction (probably the main culprit), height data, calories, etc......

 

[Hacienda71]

It is annoying when the display on the Garmin gives you one figure then you download the ride and get something different.

 

[Sittingduck]

Strava definitely penalises you more if you are doing a lot of stop/start riding.

 

[uclown2002]

Strava is evil though as if you bust a gut to reach a xy.0 mph average it insists on lowering that by 0.1.

 

[Buzzinonbikes]

Don't know but you are rapid

 

[I like Skol]

Don't know but you are rapid

It does look like that until you check the altitude trace. It is one long downhill, he barely has to pedal

Even @potsy could probably post a 20mph ave on that section

 

[I like Skol]

Respect, just looked at the return trip from a couple of days before and still averaged over 19mph!

 

[Hacienda71]

It has done it again this morning. Lost .5mph on Strava over Endomondo and my Garmin. They need to sort it out That is pretty noticable variance. I think I will PM Strava support.

I have seen @potsy going far faster than that down hill.

 

[potsy]

Respect, just looked at the return trip from a couple of days before and still averaged over 19mph!

Who do you think he was drafting?

 

[HLaB]

Strava is usually for me 0.1mph lower on average than the gps and other sites; I dont think Strava takes account of auto pause in the same way as GPS, Garmin Connect, RWGPS, etc.

Its usually a bit lower too on the elevation data and top speed (although last night was the exception strava recorded a top speed of 33.6mph and GC 33.5mph).