Harry van der Wolf <[email protected]> writes: Defining terms I'm using (and being not entirely precise, ignoring a lot that doesn't matter for this discussion)
ellipsoidal height: distance above WGS84 reference ellipsoid, as geometrically measured by GPS. Not typically used by normal humans. orthometric height: distance above the standard equipotential (equal gravity) surface. What people usually call "elevation". In the US, NAVD88 is the current vertical datum, and fits in this category. geoid model: coefficients that vary with location to convert between ellipsoidal height and orthometric height > Your Garmin is maybe internally corrected for that, butOsmAnd does a > "clean" calculation based on the GPS info, and uses that map for altitude > correction. I think you are saying (and extending) that OsmAnd is getting ellipsoidal height from the internal GPS receiver via a standard Android interface (and either not getting orthometric height or ignoring it) OsmAnd has a geoid model that might or might not have been downloaded by the user without the geoid model, it shows ellipsoidal height as "altitude" with the geoid model, it applies it and thus shows a GPS-derived orthometric height as altitude Is that right? And you didn't address do the builtin GPS receivers in phones have a geoid model, like a standalone unit typically does? Is osmand ignoring it, or is it often not present? Also, I would not be at all surprised if various phones behaved differently and that some of them did not follow the spec, returning orthometric height labelled as ellipsoidal height. I would recommend to Isaac to run "SatStat", which shows "elevation". I am not quite sure if that is ellipsoidal height or orthometric height. However, it's another datapoint. -- You received this message because you are subscribed to the Google Groups "Osmand" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. For more options, visit https://groups.google.com/d/optout.
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