How to determine TimeZone / UTC by address or GPS coordinates?

Question

Working with date/time

Colleagues tell me!
How to determine in PHP or JS TZ or UTC having, say: city / region / state / GPS coordinates ..
taking from the browser is not an option. The essence of the task: a certain address is indicated and the time is set from it..
Google threw the idea www.iana.org/time-zones , but I didn’t know a little what could be done with this base..
Help :)

Answer 1

If you need accuracy, then you need not just a base with time zones, but a map with them. Further, this map must be put, for example, into the SpatiaLite (SQLite) database and a spatial request should be made to enter a point with given coordinates into the map area. If you only have the name of a place, you need to first get the coordinates of that region to check in the same way.

Answer 2

What for? If you do not have a specialized site tied to the user's time (such as a calendar), then it is better to move all date conversions to the front-end and completely forget about them on the back-end, working in UTC.