I've noticed a MASSIVE improvement in elevation correction in the past <year. This is one thing Garmin is doing right. It's scary accurate on both little dunes at the beach, and steep rolling hills in the remote country. Two things that historically, elevation maps based on topo lines got very wrong. So I'm just wondering where they're getting their data now. Satellite radar? Crowdsourcing from Garmin Connect users with barometric altimeters? Anybody know?
Really, no one knows the answer to this? Or Garmin's people just aren't saying?
It makes a difference how much I want to trust the corrected data vis-à-vis the barometric. Like I said, the profiles are scary close, but there's a rather large smoothing difference in the total. If it's from topo lines, with the kind of terrain I run and ride in, I'm going to trust the barometer a lot more. Anything less than 5 meters is going to result in an overly smoothed total, and when the hills are as steep and as plentiful as ours, the short ones do matter.
Since GC defaults to uncorrected when the activity comes from a device with a barometric altimeter, is that their own judgment that the barometer is more accurate? Or is it just a legacy from the earlier version of elevation correction?
I would suspect that it's contained in the map database. So the short answer might be that it's provided by the company that supplied the map you use on GC. Now where they got the data is a lot more involved. Likely it's an amalgamation of data from many different sources.
If it's not in the map database, then certainly I would think they purchase the information from some other company. I'd think it highly unlikely they build their own DB.
