[andorany]

today I did a hill climb. the local bike club called in 750ft climb in two miles, my garmin picked up 702 feet...fair enough they most likely rounded up and such. I turned on "auto correct" on Garmin connect and it jumped to 820ft climbed...I've had a few other rides that a bit screwy too (same route, different feet climb). Has anyone else had issues? which one is most accurate, "auto correct" or the device?

 

[looigi]

It's complicated, but basically auto correct uses the devices data and corrects it for drift and offsets so is more accurate. Device based elevation gain is usually more than map based elevation gain because the device will record many smaller ups and down that are not contained in the map data. The device can also record fake ups and downs that are caused by pressure variations from gusts (depending on how/where it's mounted), the port getting clogged by water in the rain, etc.. For example, if you pointed the pressure ports directly into the wind going 40 mph, the resulting increase in pressure would make the device read ~800' lower than actual. Aim the ports in the opposite direction would make the device read higher than actual.

 

[ph0enix]

Don't let it bother you. There will always be fluctuations in the reported elevation data regardless of the measuring device being used. The Garmin just gives you a rough idea of how much you climb.
...BUT I recall reading somewhere that the Garmins need to sit powered on for a few minutes before riding in order to orientate themselves correctly. See if that helps.

 

[kevhogaz]

I find that my 510 is way more accurate on Garmin Connect, as compared to other riders on the same ride, than STRAVA. On STRAVA, my elevation and calorie gain is sometimes almost double what the other riders are showing. On Garmin Connect, they're almost exactly what the other riders show.

I emailed STRAVA, and they're supposed to be fixing the issue. They said there was a problem with the way the program was written, and they were trying to come up with a solution.

 

[drussell]

If it's a climb you do frequently, look up an elevation point(s) on a proper topo map (preferably one near both the bottom and top) and enter that into the 510 (I'm assuming you can do this with the 510, as you can with the 500). It will use those control points to improve the accuracy of your elevations.

 

[Eric_H]

On the 500, you can input many elevation points but my understanding is that they only work if you are pressing "Start" at the location of the elevation point. So in reality, only at the start of your ride. Just riding past a programmed elevation point on the Garmin 500 does not do anything to register or correct elevation.

 

[TrojanHorse]

I don't know that "autocorrect" is more correct than the pressure sensor method. I've found it to be the opposite UNLESS I'm riding in a really windy area. It correlates survey data to the track you rode, but sometimes the survey data is whacked too.

Just pick one and stick with it. Little variations aren't going to kill you.

 

[looigi]

I don't know that "autocorrect" is more correct than the pressure sensor method... Just pick one and stick with it. Little variations aren't going to kill you.

"Elevation Corrections" in Garmin Connect use the pressure sensor data, but adjusts it to match map elevation data at corresponding points along the route. When you do a ride that starts and ends at the same point , often you see the elevations are different in the uncorrected data. When you turn on corrections the elevation graph looks pretty much the same, but the discrepancy in start/stop elevation will be fixed (as will similar errors at other points along the route). Occasionally, the raw elevation plot might have a big error in it, perhaps due to water on the pressure port, wind or who-knows-what. Elevation Corrections will usually fix these issues too.

But yes, the variations don't really matter that much. Stick with one method and ride.