On 2019-11-23, at 13:18:46, Guy Harris wrote:
See https://www.geonames.org/export/web-services.html#timezone
although they are rate-limited. I think Ubuntu may do a bulk download of the database and use it for their own server, used for the Ubuntu time-zone-selection mechanism.
Thanks. Example http://api.geonames.org/timezone?lat=47.01&lng=10.2&username=demo Produces unrendered XML (CSS somewhere) from which I can copy-and-paste zoneinfo path.
My phone uses the result it gets from Location Services ... (or entered in Settings; limited gazetteer.) ... and turns it into a tzdb ID internally. (but only internally)
... So does my Mac, and the way I display the zone info path is
$ ls -ld /etc/localtime lrwxr-xr-x 1 root wheel 45 Oct 4 03:47 /etc/localtime -> /var/db/timezone/zoneinfo/America/Los_Angeles
(your mileage may vary on macOS Catalina if that's on a read-only file system).
On Mojave, I enabled "Full Disk Access" for Termimal.
I don't know whether Apple have their own image maps. This project:
https://github.com/evansiroky/timezone-boundary-builder
is "A tool to extract data from Open Street Map (OSM) to build the boundaries of the world's timezones." I don't know what geonames.org uses - it may use somebody's shapefiles or it may rely on people associating tzdb IDs with locations.
Thanks again, gil