[Design] [Scooby] Managing Calendar/Timezone

[Bobby Rullo]

On Apr 19, 2006, at 12:08 PM, Steve Lewis wrote:

> Bobby Rullo wrote:
>> Also possibly a 3rd:
>> 3. System "guesses" initial timezone based on IP address to  
>> location table for initial log in
>
> [delurk]
>
> A fourth possibility would be to detect their timezone every time they
> log in.  If the current client's detected timezone is different,  
> ask the
> user if he/she would like to adjust the user's timezone, and the
> calendar view, to use the detected time zone or continue to use the
> stored timezone.
>

Interesting idea. We'd have to make it annoying proof so that the  
dude who always wants their timezone to be EST even though they are  
in CA doesn't get harassed.

> You can determine the timezone without the IP address to location  
> table
> which has a significant margin of error.
>
> As a hint toward implementation, adapt or adopt this javascript  
> library:
>
> http://west.ilrn.com/media/js/systemCheck/timezone.js

That only works if the system's time has changed.  Like someone went  
to the System Preferences panel and clicked "change timezone" Might  
not always be the case for laptop users who are bouncing around a lot.

> and then search java.util.TimeZone for a timezone that has the same
> summer and winter DST offsets, then filter that down further by
> timezones that switch DST at the amount.  This will often give several
> possible but equivalent matches.  Programmatically solve this by  
> always
> choosing one, e.g. the first.
>

The problem I see with this approach is that it would have to favor  
some locale's over others - New York and Buenos Aires might have the  
same offset, but which one would appear first in the list? Americans  
would be annoyed if Buenos Aires always appeared first because it  
begins with B and Argentineans would be annoyed if New York appeared  
first just because it's American...

Is the margin of error for IP address tables really that bad? We  
don't have to get within a block, just within the general region.  I  
thought they were ok for that, but don't really have any data to  
support it either way.


Bobby