Anyone know of a web service or web site that will report the UTC offset for a specified grid square or latitude and longitude anywhere in the world?
I don't think that is actually possible, at least not for grid squares. Time zones are political decisions.
There's all kinds of strange anomalies.
1. Some jurisdictions are 30 minutes off. That is, they decided to be so-and-so hours plus 30 minutes different from GMT. Good luck discovering which (India happens to be one -- I just looked it up). It's not always obvious why the choice was/is made.
2. Some jurisdictions ignore their geographic location. Iceland is on UTC when it should agree with Azores.
3. "Daylight time" varies by the time of year and of course some jurisdictions don't participate. Worse, the changeover times of these things have and probably will continue to vary over time. So, you have to know the time of year
and the political entity.
4. I have no idea how one would properly set the time if one is in the open ocean with no land masses in the grid. It probably is based on the captain's whim.
You are sitting on a piece of dirt somewhere. Your four letter grid tells you not nearly enough.
But, if you know what political entity that piece of dirt belongs to, well, one way or another, you can easily look it up.
There may well be grids that straddle political boundaries, each with a different time zone. Near me, some four letter grids straddle New Mexico and Arizona. The time zone will vary based on which part of the grid is in one state versus another.
You just might be able to get pretty close with six letter grids. But, political boundaries don't reliably follow grid lines no matter how fine it goes. What error rate will you tolerate? DXMaps makes a reasonable guess, but at the margins, it is likely to be wrong.
If you use actual lattitude and longitude of fine enough grain, then with the right kind of database, you might be able to make that work.
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Topic: New, improved accurate time and timezone info (Read 291 times)