Originally Posted by
a1penguin
I think you have to consider the altimeter on the phone. I have a Garmin Edge 500 on the bike, but use Strava on the phone for hiking. My friend uses two other apps to do the same thing and he has a different phone. Surprisingly, the distances often differ by 2-3% but the elevation is fairly close. I've never looked at the raw data to see if this is missing points that Strava fails to fill in or what. Stopping and starting and other motions can affect the data stream. You can probably find some forums with hard core GPS folks who can provide more details and assessment of various devices and software.
Overall, I'm happy with Strava. It's just recreation, not rocket science for me and I am happy with the data I get.
2% difference is acceptable. Two GPS devices will pretty much always disagree a little about how far they've traveled.
Sunday I did a ride around Camano Island with a Garmin Edge 800 and a Garmin Fenix 3, you'd think they would agree perfectly but one said 30.06 and the other said 30.15 miles. That's pretty typical. When you think about all the tree cover that the GPS signal traveled through, it's kind of amazing they agreed so closely.