Subject: [calsify] Timezone question

From: "Tim Hare" <[email-masked]>
Date: Tue, 17 Jan 2017 09:27:11 -0500

This is more of a usage question, probably, but this has come up due to
travel, and I thought I'd ask the experts.

Let's say Bob lives in the America/New York timezone;  travels to Australia
(crossing the International Date Line); and while in Australia needs to set
an appointment in Los Angeles.  

There are three timezones to worry about when creating an event - the home
timezone of the device, the timezone the devices is in _now_ (usually set
due to location services), and the timezone of the event, correct?

So, when creating an event, Bob should always:

1. Ensure that timezone support is  turned on in the device
2. Set the timezone of an event when creating the event

The timezone of where the device _is_ shouldn't matter, if you are following
those two rules?   If creating a VEVENT in software, then the timezone
should always be set, correct?

I used to think leaving the timezone off was a solution - but then the
software on devices started assuming the timezone of an appointment without
one, and that didn't always work well.

Thanks 
Tim Hare
Interested Bystander, Non-Inc.

---

From: Michael Douglass <[email-masked]>
Date: Wed, 25 Jan 2017 22:32:01 -0500

> due to location services), and the timezone of the event, correct?
At least - could be more
> should always be set, correct?
Correct
> one, and that didn't always work well.
That's floating time and the specs don't make this clear but floating 
time has very few valid uses - even though it gets used all the time.

Floating time is really to handle the sort of case where you want an 
event in your calendar that happens at the same time of the day - 
wherever you are. For example, you might got for a run at 8am - you have 
your lunch at 12 noon. You could set these as floating time and then 
they would show up at the correct time - assuming that the appllcation 
truly knows what the local timezone is. It might work OK on your phone 
but with shared calendars it's probably going to show up at a number of 
different times on different calendars.

Really what needs to happen is that certain events need to be tied to 
your physical location - that could be done by nominating your phone as 
the 'home' device. Works OK until you go for that flight to Australia 
and forget to take your phone.

The same thing is true of meetings. Many - perhaps most of us - now have 
meetings - social or business - which involve multiple timezones. It 
would be useful to have the attendees CURRENT timezone reflected in the 
event. That way it's clear if we are scheduling a call at 3am in the 
morning for someone.

I suspect that what's emerging is that the timezone should be attached 
to a person or a location and may change over time - sometimes quite 
rapidly. Then we link certain attributes of the event to other 
attributes - so an event may have a starting location and an ending 
location and those 2 timezones matter. The start time is linked to the 
start location and the end time to the end.  (and i hear an argument 
developing but there needn't be an end time specified - but even if it's 
calculated from the duration its local value depends on the end timezone.

The technology to do most of this already exists - a small spec change 
could associate timezones with attendees. Each change to an attendees 
timezone could trigger an iTip update. Probably more work changing the 
clients...

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