>From SatStat: Moto Z Play internal GPS: 712'
Z Play on Garmin Glo: 813' Xoom internal GPS: 721' Xoom on Garmin Glo: 813' On Sunday, February 18, 2018 at 9:49:52 AM UTC-5, Greg Troxel wrote: > > > Harry van der Wolf <[email protected] <javascript:>> 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.
