Originally Posted by
smarkinson
If we look at what strava is doing consider this set of elevation data:
23.4, 23.5, 23.6, 23.7, 23.8, 23.9, 24.0, 24.1, 24.2, 24.3
...
Garmin would record this as something like this:
23.4, 23.4, 23.4, 23.4, 23.8, 23.8, 23.8, 23.8, 24.2, 24.2
This isn't adding up the rounded increments like you were doing, but it is looking at absolute elevations. Which is what I said to do, with local minina and maxima.
If instead Garmin is just doing the step and ignoring anything below a .4m change, until it reads a higher change, then it's potentially missing a lot Anything less than .4 meters, up and then down, isn't recorded. Potentially every other sample could be missing a rise and a drop of up to .4 meters.