dbikingman

How can I figure total elevation gain for a ride. I have a garmin and shows me elevation gain and descent, but it doesn't equal zero even on an out and back ride.

mwchandler21

I think the Garmin Edge figures elevation based off of barometric pressure. Its close but not completely accurate. I once rode through a sudden thunderstorm and the elevation profile for the ride showed a 300 foot drop in elevation around the spot of the storm. On a day when the weather doesn't change it rarely comes out perfect but it is usually close. Anyway I wouldn't worry about the numbers not being equal and just take the value for the elevation gain to be a close value.

jayp410

It usually takes about 3-5 minutes for my 705 to reach a steady elevation after turning it on. Usually the start and end elevations are pretty close if I turn it on early enough before the start of the ride.

If the start and end do end up being significantly different, adding (or subtracting) the difference between should be a good correction.

TrojanHorse

You can always upload the gpx file to a site like mapmyride.com or something, they use measured elevation (er, they get it from the map, not from any pressure gauge on your GPS).

jayp410

Except that MapMyRide is notorious for grossly underestimating elevation changes, especially if your ride involves many rolling hills (as is the case in my area). The problem is that it only uses elevations at certain contours, and if the hill is relatively small compared to those contours, it's just guessing in between. Also I have heard that MapMyRide uses additional logic to "smooth" out the rolling hills. Barometric-based readings are much more accurate IMO, although it's possible that other map-based sites do it better than MapMyRide.

If barometric measurements were very inaccurate due to weather changes, the totals (over the same course) would be different on different days. What I've found with my 705 is that the totals only differ by about 50-100 feet for the same 25 mile training course that I often ride, which is not that bad.

cappuccino911

i use runkeeper for my droid and it comes out almost double what the elevation people on similar routes get using a garmin. one day i used both runkeeper and mapmyride on my droid and same thing, runkeeper was almost doubling the distance. I dont really know who to believe but everyone seems to say the garmins are the real deal. Is gps able to measure actual height? i thought it was?

indyfabz

You can say that again. The web site for the Grand Fondo here in Philly had a link to the route on MapMyRide. The 107 mile route showed only 4,000 something feet of climbing. I was familiar with all the roads and said to myself "No way is that only in the 4000s." Turned out it was more than 7,000 ft.

MrClyde

Have you tried uploading to Garmin connect, and selecting the elevation correction option?