Joseph Eisenberg <joseph.eisenb...@gmail.com> writes: > Is there a reason to use this new tag ele:regional instead of ele:local=* > which is already mentioned on the Key:ele page?
The notion of "ele:regional" is semantically wrong, because there is no way to map a particular lcoation to a single vertical datum. The notion of "local" has the same problem, and it is also a poor choice of words in that in surveying, "local", refers to coordinate systems established for particular projects or surveys that have no lasting significance. I have tended to say "regional datum", because in the US we share NAVD88 with Canada, and because I have the impression that in Europe multiple countries share a vertical datum. Basically, either you know what datum an elevation is in, in which case you can 1) transform it to WGS84 height above geoid or 2) label it correctly, or you don't know, in which case you should simply *admit that you do not know*. I would also ask: if this is reasonable for height, why isn't it also reasonable for horizontal coordinates? _______________________________________________ Tagging mailing list Tagging@openstreetmap.org https://lists.openstreetmap.org/listinfo/tagging
