strava

[Big_Dave]

my night ride a couple of days ago, garmin 800 (barometer) unit itself read 2185ft, uploaded to garmin site, with elevation correction it said 1710ft, strava with elevation correction 1699. RWGPS says 1980ft
Who knows which is correct

 

[Nigelnaturist]

I always correct my rides with rwgps for consistency, how ever last year using the Edge 500 there were peaks and troughs which I think gave a false elevation apart from april, my average this year is between 37 and 40ft/mile last year between 43 and 46ft/mile

 

[Big_Dave]

I always correct my rides with rwgps for consistency, how ever last year using the Edge 500 there were peaks and troughs which I think gave a false elevation apart from april, my average this year is between 37 and 40ft/mile last year between 43 and 46ft/mile

I've just had a look on Strava and RWGPS at the elevation on Holme Moss and they both read 1725ft, the road sign says it's 1719ft. Although this was with a Cateye GPS without a barometer.

 

[Nigelnaturist]

I've just had a look on Strava and RWGPS at the elevation on Holme Moss and they both read 1725ft, the road sign says it's 1719ft. Although this was with a Cateye GPS without a barometer.

Its not the height that is really an issue, but how strava calculate elevation gain, do this take any ride a create a segment for the whole ride, and you will see elevation gain of the segment is much closer to rwgps and the units gain.

 

[bpsmith]

My mate and I both bought a Garmin 510 last year, from same place and on same day. His elevation data is always a few hundred feet more than mine. Was difficult to compare as he did have one hill more than me to climb, although it was a small one so doesn't equate to the difference.

I investigated my previous rides and found a lot of mine read as being below sea level when riding along the coast roads.

I sent mine back to Garmin and it was then replaced. The sea level thing is now fixed, but my mates still shows as greater elevation. We recently did the Black Mountain climb. I rode to his house to meet and rode passed his on way home too. A couple of small hills more for me. Elevation data....still a few hundred feet in his favour! Go figure?

 

[Nigelnaturist]

The use of a barometric meter in unit is not very reliable, as it is susceptible to versus atmospheric conditions, sudden low pressures like storms can effect it, also the temperature of the unit effects it (more so when its cold), ideally the unit should be placed out side at least 10 mins prior to a ride, this gives the unit time to acquire the correct elevation and temperature, also many units have the option to set way points with the correct elevation i.e. home, when you start at this point it will set the elevation to the correct height, however if the temp of the unit is still higher than the ambient temp you will tend to lose elevation, i.e. you will have more loss than gain on a route bring you back to the same point, 30 miles maybe 30ft or so, sometimes more.

 

[bpsmith]

I read similar and quizzed my mate before, to see if the above behaviour was different between us.

Neither of us set waypoints. We both position on the bike using the same standard mount. We have the unit outside for 10 mins or more before setting off. I am comparing rides done together, so the conditions are the same. Can't make much more sense of it, but his readings are always higher!

 

[Nigelnaturist]

@bpsmith the only other thing is the technology isn't that accurate, of all the measurements a gps unit can make it is the least accurate.
RWGPSCEG= corrected elevation rwgps, R20 the elevation according to Brytons site for the R20, and 705EG data from Garmin Training Centre, which is supposed to be the raw data.

You can see that the R20 is consistent, but very low (like strava) even the corrected data from the 705 on rwgps fluctuates as does the raw data, however the differeance between rwgpsceg and the 705eg is usually within 10%, that of the R20 is usually closer to 50% (though if corrected on rwgps it is closer to the true elevation)

However in the last 2-3 weeks the 705 has been throwing out some wacky figures.

One ride in particular is when I reset the unit at a friends, it generally only shows 1ft of elevation gain on the ride home however when loaded into the appropriate software or uploaded to websites it always shows the elevation as being more than 1ft.

 

[bpsmith]

@Nigelnaturist interedting stats once again sir.

I take your point about the results not being reliable and your stats prove that in fairness.

My complaint is that I never get them skewed my way, ever! Lol.

In fairness though, he does a lot more climbing generally, so I would never expect to match home. Does get annoying when we do the same routes nonetheless.

 

[Nigelnaturist]

@bpsmith the thing I noticed last year when using a 500 was there were many peaks and troughs when corrected on rwgps, that you don't seem to get with the R20 or 705 (something in conversion of the fit file I think). I use the corrected elevation in my database for things like average V.A.M. a ft/mile calculations, and it only the fact that I seem to be 10ft/mile less than last year over much the same sort of riding, however the couple of months before I started using the 500 the corrected data from the Nokia N95 is much closer to the current data.

 

[bpsmith]

I will have to start doing some stats to compare it seems. Will set something up over the Winter methinks.

 

[bloodlett]

I use strava for the multi media aspect for record keeping I prefer Garmin connect I live close to sea level and my Garmin 500 is real close on elevation

 

[bpsmith]

I use strava for the multi media aspect for record keeping I prefer Garmin connect I live close to sea level and my Garmin 500 is real close on elevation

We live near the sea too and both use Garmin Connect too. The results are the same on that also.

 

[bloodlett]

it will be awhile before I start training on a grade the only hills around me is bridges over the intercostal water way but I can get accurate grade and elevation on the bridges and compare to my edge 500 but when I start the screen flashes elevation point found not sure if I set it up like this or what I don't care about it for now it will be 2 or 3 months before I am fit enough to start training for climbs