> Storing (UTC, latitude, longitude, altitude) is the holy grail, I guess. It’s not. If I set up a meeting next year in NYC at 10 and the legislature decides

> Storing (UTC, latitude, longitude, altitude) is the holy grail, I guess. It’s not. If I set up a meeting next year in NYC at 10 and the legislature decides to change the timezone’s offset, the meeting remains at 10 NY time on that date, it does not shift in NY time. It’s the UTC which shifts. And UTC alone is sufficient for past events, as they are fixed instants in the time-stream. Unless you’re at a stage where you need to take relativistic effects in account, then you need to add the referential.