On Mon, Jun 06, 2016 at 01:09:34PM -0400, greg crago wrote:
Since I cannot seem to get this feature added to the OSM database
(because it is not verifiable, or something) has anyone got this data
from a different source and combined to maps together so I can tell
when riding across the counrty thay I am crossing a timezone??
I would expect time zone to be an (explicit or implicit) attribute of a
boundary=administrative relation. That is, the whole country or state
(or province or city) would use the same time zone.
If the above does not apply (for example, if some US state is being
divided by a time zone boundary), then some overlay of an external data
source would indeed seem to be needed.
http://wiki.openstreetmap.org/wiki/Key:timezone seems to agree with my
reasoning above. It also refers to a changeset that introduced time
zones for the Australian states. However, all those modified objects
have since then been removed, and the new Australian state relations do
not seem to include timezone=*.
http://taginfo.openstreetmap.org/keys/timezone lists a number of values
starting with America/*. Maybe the US states are already tagged?
There is also an algorithmic problem of extracting boundaries of tagged
areas. Even if all the administrative areas are tagged with timezone=*,
we would want to derive the boundaries, so that only those
administrative boundaries that also represent a time zone boundary (with
different values on each side) will be displayed.
Best regards,
Marko
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