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Strava elevation data difference iPhone/Android and Garmin

Posted: Fri Jan 03, 2014 3:11 pm
by jsprbcn
I know this is a known issue as telephones does not come with a barometric sensor for the elevation data, but still I want to get this of my chest :mrgreen: :mrgreen:

How can or how could we solve this so it's fair for everybody?


Should Strava:
- Take away the elevation data for phone users?
- Make Strava GPS device only?

An example:

A friend accumulated over a ride of 100Km, 2016m elevation difference with an iPhone.

Strava
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I did the same route a while ago and got over the same 100Km, 1503m elevation difference with a Garmin Edge 500 (calibrated before leaving home). I even did a little side trip which included some more climbing (check the circle in the elevation profile).

Strava
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Garmin Connect
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I'm curious about your opinions regarding this.

Thanks!

Re: Strava elevation data difference iPhone/Android and Garm

Posted: Fri Jan 03, 2014 6:14 pm
by FIJIGabe
I've never been able to accurately gauge the elevation using the Garmin 500/810 units I've had. Heck, even when comparing the same data file, Garmin Connect and Strava post different calculations for almost everything (even speed and distance). It's hard to take their calculations as more than an approximation based on the inconsistencies.

Re: Strava elevation data difference iPhone/Android and Garm

Posted: Fri Jan 03, 2014 6:14 pm
by Weenie

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Re: Strava elevation data difference iPhone/Android and Garm

Posted: Fri Jan 03, 2014 6:38 pm
by bombertodd
The problem is the phone users get elevation from a topographic map. If riders ride over man structures such as bridges, overpasses, or cutouts from mountain passes it screws up. Strava calculates the rider going down into the stream and back out, where as the garmin reads the pressure as staying level. The garmin still has some accuracy issues but it generally seems much more better then the phones where I live.

If I ride from my house to Crestline it's about 50 miles round trip with 3,500 feet of climbing. Strava reads over 6,000 feet of climbing. There are a lot of bridges and mountain cutouts.

I wish strava would get rid of the phone stuff, but they make a lot of money off of phone users too. They don't want to bite the hand that feeds them.

Re: Strava elevation data difference iPhone/Android and Garm

Posted: Fri Jan 03, 2014 7:32 pm
by Nebby
You're totally right. It's really messed up how the elevation works for phone users, but the money factor is a big consideration for Strava.

Re: Strava elevation data difference iPhone/Android and Garm

Posted: Fri Jan 03, 2014 7:49 pm
by kulivontot
My garmin 305 would consistently read an addition 150m than my friend's iphone on certain rides, so it's all relative. I bet the newer garmins would read different as well. Who the hell knows which is right? I've had the barometric sensor read certain gradients as 15-20% when it's really windy as well. Other than bragging rights, who really cares? The GPS coordinates should be the same, so you still know who's the fastest up an individual climb, and the calculated power data is garbage anyway. If you really want an even playing field, then just always use the topographic elevation data.

Re: Strava elevation data difference iPhone/Android and Garm

Posted: Fri Jan 03, 2014 9:03 pm
by bombertodd
The issue with the topographic elevation data is that it is clearly wrong in most areas (unless it's really flat). The problem is with our club is newer people that use phones is they ride a ride with 3,000 feet of climbing at an average speed of 15 mph. Their phone said they rode a ride with 6,000 feet of climbing at 15 mph. They show up to a posted ride that said, "60 miles with 6,000 feet of climbing with 15-16 mph pace." They show up and get dropped. Some of the group gets upset because this person can only ride about 13-14 mph average on a 60 mile with 6,000 of climbing. It happens in our club all the time when we hit the mountain routes.

Re: Strava elevation data difference iPhone/Android and Garm

Posted: Sat Jan 04, 2014 1:09 am
by kulivontot
That only happens once, data is one thing, but at the end of the day you know whether you can hang or not. Strava is like fantasy football, you can judge all the stats, but at the end of the day you can't really know who's going to perform on any given day.

Re: Strava elevation data difference iPhone/Android and Garm

Posted: Sat Jan 04, 2014 1:52 am
by Powerful Pete
I have just begun using Strava with a phone (no Garmin device). I notice that it registers different elevation for the same training route... oh well.

Re: Strava elevation data difference iPhone/Android and Garm

Posted: Sat Jan 04, 2014 5:28 am
by bombertodd
kulivontot wrote:That only happens once, data is one thing, but at the end of the day you know whether you can hang or not. Strava is like fantasy football, you can judge all the stats, but at the end of the day you can't really know who's going to perform on any given day.


It seems to happen at least once a month with our group. People gain and lose fitness and new people start riding with us. It makes it almost impossible for phone users to judge if they can hang on a hilly ride. It sucks getting dropped and it sucks having to wait a long time for slower riders too. Especially when riders are on time crunch (such as mid week after work rides).

Re: Strava elevation data difference iPhone/Android and Garm

Posted: Sat Jan 04, 2014 7:51 pm
by kulivontot
I don't think that's going to go away should everybody be using garmins.

Re: Strava elevation data difference iPhone/Android and Garm

Posted: Sat Jan 04, 2014 9:31 pm
by jsprbcn
Another one from today, and the exact same route regarding the climbs:

104,2Km with my Garmin 500: 782m elevation
105,9Km with iPhone: 1630m elevation

That's double!

Re: Strava elevation data difference iPhone/Android and Garm

Posted: Sat Jan 04, 2014 11:29 pm
by Frankie - B
It is the other way around over at us. Holland is quite flat, and the phone users usually get the better altitude profiles then the Garmin users. the reasons being the same. GPS users get more altitude meters, because of the barometric sensor in their device. Phone users usually get better data, because the only climbing around here is an overpass.

Re: Strava elevation data difference iPhone/Android and Garm

Posted: Sat Jan 04, 2014 11:29 pm
by Weenie

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Re: Strava elevation data difference iPhone/Android and Garm

Posted: Wed Mar 12, 2014 6:11 pm
by ARL002
kulivontot wrote:That only happens once, data is one thing, but at the end of the day you know whether you can hang or not. Strava is like fantasy football, you can judge all the stats, but at the end of the day you can't really know who's going to perform on any given day.


I think the issue is that the stats in this case are wrong, or at least different according to the measurement device (akin to perhaps comparing your performance based on weekly points in a Yahoo! league and an ESPN league).

I've only used the elevation information to compare to my previous efforts, so as long as I maintain a consistent method, I can see the gains (or losses) accurately. Sounds like some folks are using it to compare level of fitness to keep up with a group, not sure that you can get around this. As with any social media company, Strava values # of members more than anything (with phones providing easy entry for newer riders).