Garmin Elevation Difference

[wam68]

Hi Folks,

I was out on a club ride yesterday and on my return I loaded my data onto Strava. When looking at my elevation there was over 400 meters difference between my Strava reading and the rest of my club mates who were all within 20 meters of each other. This is the 2nd time this week there has been a remarkable difference between my elevation data and companions on the same ride. I was using the 200 and all the rest of my buddies were on 500 or above.Could there be a connection between the model and the elevation inaccuracy or has anyone else experienced anything similar and were able to rectify it. Cheers for any help in advance

PS. Happy New Year ya'll

 

[Mo1959]

Hi Folks,

I was out on a club ride yesterday and on my return I loaded my data onto Strava. When looking at my elevation there was over 400 meters difference between my Strava reading and the rest of my club mates who were all within 20 meters of each other. This is the 2nd time this week there has been a remarkable difference between my elevation data and companions on the same ride. I was using the 200 and all the rest of my buddies were on 500 or above.Could there be a connection between the model and the elevation inaccuracy or has anyone else experienced anything similar and were able to rectify it. Cheers for any help in advance

PS. Happy New Year ya'll

The 200 doesn't have the built in barometer so works out elevation purely on map data. I always used to feel it didn't take into account all the little undulations in the road the same as the 500 and above which have the barometer. Not sure how it works. No doubt someone else will come along with the technical side of it, but I think the gist of it is that it senses all the rises and falls in the road due to picking up barometric pressure or something??

 

[Massivecompacthalo]

I think it's because the 200 uses GPS based calculations and the 500 and above have a barometric altimeter.
Check out DCRainmaker.
http://www.dcrainmaker.com/2010/05/understanding-sport-device-gps.html

 

[Colin_P]

I use a 200 as well. These rely on an algorithm run on the base map, so is really a best guess.

The posher garmins do have a barometric pressure sensor in them which also use an algorithm on the base map data, again it is a best guess.

Which of the two guesses the best I don't know. I've double checked a few rides using other data sources and things seem to be quite accurate. I believe the posher ones over read and also believe the algorithm is flawed on the posher devices.

Regardless, they are all best guesses.

 

[wam68]

Thanks folks for the prompt & outstanding replies.

Problem and remedy explained. It looks like I'm gonna be shelling out some more money on a 500 at least.

Thanks again

 

[Crandoggler]

Can I make a suggestion?

http://www.amazon.co.uk/Polar-M450-GPS-Bike-Computer-x/dp/B013FU43M2?th=1&psc=1

Review:
http://www.dcrainmaker.com/2015/06/polars-cycling-computer.html

 

[Colin_P]

Thanks folks for the prompt & outstanding replies.

Problem and remedy explained. It looks like I'm gonna be shelling out some more money on a 500 at least.

Thanks again

The 500+'s still guess.

 

[Milkfloat]

TBH even the ones with barametric sensors in are not always perfect. A week or so ago on a group ride I allegedly climbed 1000ft less than the others (all barametric). You can force Strava to fix it though and it uses basic elevation data.

 

[wam68]

Can I make a suggestion?

http://www.amazon.co.uk/Polar-M450-GPS-Bike-Computer-x/dp/B013FU43M2?th=1&psc=1

Review:
http://www.dcrainmaker.com/2015/06/polars-cycling-computer.html

Nice Link. Given me something to think about. Cheers

 

[bpsmith]

Strava uses the US owned data. It's accurate to within 10-20 metres within the US. That accuracy figure falls to within 75 metres outside the US! Add to this that some people have their Garnin's set up differently. Mine records at 1 sec intervals. Default is 5 secs I think?

Have had this debate a lot with mates.

 

[Tom B]

I'm still getting used to my 520 but I was surprised a couple of days to see that my elevation rose 11m over about 200m of gentle incline. Upon looking back ove the distance observed the elevation rose by less than one story, however did go up by something nearer to 11m over a longer distance, I just put it being a bit delayed in responding.