[tz] Ambiguous abbreviations for Australian timezones when daylight savings is in affect

David Patte ₯ dpatte at relativedata.com
Fri Mar 29 01:09:54 UTC 2013

I believe we should have a vote on this, because it comes up too often, 
and there seem to be a few strong voices that are blocking this from 
being resolved. The vote should only provide two options: should we stay 
with the current australian tz abbreviations or not.

If not, then we can vote on what we prefer.

For those blocking this from being fixed, the most common excuse is that 
tz is not supposed to impose its own abbreviations upon its users, but 
by not going with anything the Australians are using -  tz is doing 
exactly that.

On 2013-03-27 22:33, Timothy Arceri wrote:
> Hi All,
> I’d like to bring this very important issue back up for discussion. I’m going to
> attempt to address the reason why this change is needed as clearly as possible
> while addressing the concerns from previous discussions. The issue is with both
> EST (Tasmania, Victoria, New South Wales, Queensland) and CST (South Australia,
> Northern Territory)
> It's well past time the Australian abbreviations were updated to reflect the
> current terms and usage. Stop the confusion and use the abbreviations
> recommended by the Australian government to try to avoid this mess.
> http://australia.gov.au/about-australia/our-country/time#daylightsaving
> As others have posted I’m not too concerned about the 'A' but as you will see
> differentiating between daylight savings times is extremely important when you
> are using this information in a system that crosses state boundaries and in our
> case an emergency warning system.
> Previous Post:
> ---------------------
> “I'm not a big fan of change for change's sake; once the database is one way I
> like to leave it alone.  For phrases, the new statistics seem to be quite
> strong; for whatever reason, Australians seem to be voting with their feet (or
> fingers) and are adopting American terminology with an "Australian", when the
> time zone names are spelled out.  For abbreviations, it's not clear whether
> "AEDT" or "EDT" is more common, though I suppose "AEDT" has a slight edge.
> I'd like to hear more from Australian correspondents on this before thinking
> about specific changes, though.” - Paul Eggert (26 Aug 2008)
> I don’t think anyone here cares deeply enough about time zone abbreviations
> enough to be arguing about change for change’s sake. The fact is the ambiguity
> of the current abbreviations for time zones is causing real world problems.
> Previous Post:
> ---------------------
> “Alphabetic time zone abbreviations should not be used as unique identifiers for
> UTC offsets as they are ambiguous in practice.  For example, "EST" denotes 5
> hours behind UTC in English-speaking North America, but it denotes 10 or 11
> hours ahead of UTC in Australia; and French-speaking North Americans prefer
> "HNE" to "EST".” - Paul Eggert (26 Aug 2008)
> The issue is not that the identifiers are not unique worldwide. The problem is
> that they are not unique to bordering states in the same country which run along
> the same time zone. Most apply daylight savings time, one (Queensland) does not,
> this is what causes the confusion. Simply using UTC +10 or UTC +11 is not good
> enough as the general public has no idea what UTC is.
> Previous Post:
> ---------------------
> “I have always assumed that the common abbreviation (EST for standard time, and
> EST for summer time) was a very deliberate choice, chosen so that if it ever was
> appropriate to specify a time with an abbreviated zone name, then the time
> specified would apply year around, which is almost always what is intended” -
> Robert Elz (5 Jan 2009)
> If all states that used EST applied daylight saving then this would be
> convenient but as stated above they do not. The problem can be seen in the
> delivery example where it would appear an Australian company does delivery’s via
> time travel.
> Previous Post:
> ---------------------
> “Queensland don't have Daylight Saving Time. New South Wales (across the border
> from Queensland) do have Daylight Saving Time. Due to the fact that the Olsen
> data uses EST for both 'Eastern Summer Time' (New South Wales)  and 'Eastern
> Standard Time' (Queensland), a delivery from New South Wales to Queensland  can
> have a pickup time of 10.30am EST and a delivery time of 10.00am EST. We like to
> be efficient but we're not that good. System users only see the EST and get
> horribly confused.” - Mick Johnston (26 Aug 2008)
> So obviously I’m pushing this for my own reason also. We currently use unix
> based systems to produce tsunami arrival times for the Australian Tsunami
> Warning System. This information is displayed on a public webpage (and as
> described above cannot use UTC convention). The issue comes into play when
> listing arrival times for the east coast of Australia, simply listing all
> arrival times as EST will obviously cause confusion especially for towns located
> near the border of NSW/QLD where it would appear to take a tsunami an extra hour
> to arrive only a couple of kilometres away.
> Currently we cannot use the default unix time zone commands and must rely on the
> use of a script to parse the time zone files and produce EST/EDT abbreviations.
> Obviously the ideal solution is to fix the EST/CST abbreviations once and for
> all so the all Australians can finally have software that produces time zones
> abbreviations that can be read by the general public and be used without having
> to provide added context.
> Note: In our organisation alone this issue has been brought up independently by
> multiple areas.
> Timothy Arceri


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