timezone-boundary-builder

Evan Siroky's Timezone Boundary Builder[0] is a good source of time zone boundary mappings. It can be used via a library in nearly any language you would want[1], or loaded directly into Postgres and used with PostGIS in queries[2] (of course, if you load it into your DB you should have a process for keeping it updated). It would be wonderful if Jiff supported coordinates-to-tz lookups out of the box :) [0]: https://github.com/evansiroky/timezone-boundary-builder/rele... [1]: https://github.com/evansiroky/timezone-boundary-builder#look... [2]: https://www.crunchydata.com/blog/timezone-transformation-usi...

It just uses the map that was generated by the TimeZone Boundary Builder[0]. It does fine for my purposes. I just figured it might be useful. One reason that I wrote it, was because I couldn't find a decent SaaS that didn't charge eye-watering prices, for a fairly slow response. I wrote it in an afternoon or two. Not really an ambitious project. I don't usually do "Show HN." Not interested in competing with anyone. If you like it, use it. If you don't like it, don't use it. If there are clear bugs, I'm always open to feedback. [0] https://github.com/evansiroky/timezone-boundary-builder

Super nice! I wanted to do an Arduino-based GPS clock that always shows the correct local time, but got bogged down getting the exact timezone boundaries. Thanks for bringing up https://github.com/evansiroky/timezone-boundary-builder !

> Earlier this year I had to write a function to find the current local time given a US address. I also did something similar earlier this year, though I used a geolocation service to translate address to lat/long coords, and then used lat/long to translate to timezone. (With shortcuts single-timezone states) I ended up using this python library for lat/long -> timezone converstion: https://github.com/jannikmi/timezonefinder Which sources its data from here, which seems like a pretty high quality source: https://github.com/evansiroky/timezone-boundary-builder/rele...

I’ve found the best way to deal with TZ conversions, is to use UTC as a common fulcrum. I convert the target TZ to UTC, using my local utility, then use my local TZ utility to convert from UTC to local. But I write iOS software, so I have very solid local tools at hand. It might be more problematic, on, say, a webserver. On a related note, I wrote this utility[0], some time ago. It uses the TZ map from the TZ Boundary Builder project[1]. [0] https://github.com/LittleGreenViper/LGV_TZ_Lookup [1] https://github.com/evansiroky/timezone-boundary-builder

They don't really bother me. They aren't AI spam, and some folks may enjoy them. It's pretty easy to not click on a link, for me. TZ are a fun project. I found that it's difficult to translate a long/lat into a TZ ID, so I wrote this[0]. Works a charm. It's based on the Timezone Boundary Builder[1]. [EDIT] Looks like I'll have to revisit the tests. The latest boundary map is much smaller, and triggers a bunch of errors. Most of my tests are just around boundaries. In the meantime, use the 2023b release. [0] https://github.com/LittleGreenViper/LGV_TZ_Lookup [1] https://github.com/evansiroky/timezone-boundary-builder

I wrote a tutorial on SpatiaLite here: https://datasette.io/tutorials/spatialite - "Building a location to time zone API with SpatiaLite" It shows how to use SpatiaLite + Datasette to build an API that can tell you what timezone a latitude/longitude point is in, using data derived from OpenStreetMap via https://github.com/evansiroky/timezone-boundary-builder Here's a demo: https://timezones.datasette.io/timezones/by_point?longitude=... - add ".json" to the URL for the JSON output.

I have never had an opportunity to deploy this tool, but here's a program for generating a TZ shapefile from OpenStreetMap data: https://github.com/evansiroky/timezone-boundary-builder In principle a calendar program could use its output to perform GIS lookups of locations then use the tzinfo DB to get the correct timezone at the given location and specified time.

One part of the puzzle are projects like this, giving you location to timezone: https://github.com/evansiroky/timezone-boundary-builder Mapping city to location is a classic geocoding task, for which there's APIs and tools around.