correct elevation when recording track

It would be nice if tracks captured elevation correctly on the fly and showed this in the mobile (Android) app. (I assume this would require saved maps to include enough z-data points that the app could interpolate the correct elevation at a given xy GPS coordinate. New phones--not mine--have barometric sensors that could be used, too.) At a minimum, it would be nice if after syncing with the server, the data was correct. As it stands now, a track has different elevation data when I access it via the app or via the web interface, both are wrong but the latter is much less so.