I have a Garmin Epix gps, when I do an activity I look at the data on the clock and all is well (the altitude of the areas that I know they are fine).
I synchronize with Garmin Connect, I look at the data there, and the altitude is always 30/40 meters below which puts on the clock.
It is normal? someone with the same problem?
Thanks to all.
(excuse my english :o )