[tz] Unnecessary faux transition in Atlantic/Canary 1980 Sep/28

[Howard Hinnant]

On Jul 11, 2015, at 6:46 PM, Hank Wisniewski <hankw1 at austin.rr.com> wrote:
> 
> Howard Hinnant <howard.hinnant <at> gmail.com> writes:
> 
>> My observation is that this is a lot of transitions for one night.  Would
> it not be better to delay the
>> transition from "0:00 1:00 WEST” to "0:00 EU   WE%sT” by one hour, and
> thus have only one transition
>> instead of two?  Here is a change that does so:
>> 
>> diff --git a/europe b/europe
>> index c64c41b..630c234 100644
>> --- a/europe
>> +++ b/europe
>> <at>  <at>  -2922,7 +2922,7  <at>  <at>  Zone      Africa/Ceuta   
> -0:21:16 -      LMT     1901
>> Zone   Atlantic/Canary -1:01:36 -      LMT     1922 Mar # Las Palmas de
> Gran C.
>>                        -1:00   -       CANT    1946 Sep 30  1:00 # Canaries T
>>                         0:00   -       WET     1980 Apr  6  0:00s
>> -                        0:00   1:00    WEST    1980 Sep 28  0:00s
>> +                        0:00   1:00    WEST    1980 Sep 28  1:00s
>>                         0:00   EU      WE%sT
>> # IATA SSIM (1996-09) says the Canaries switch at 2:00u, not 1:00u.
>> # Ignore this for now, as the Canaries are part of the EU.
>> 
>> Howard
>> 
>> 
> 
> Two lines were required for 1980 because Summer Time began one hour before
> the EU rules.  The second 1980 line, switching to EU rules, could have been
> specified to be effective at any time from 1980 Apr 6 01:00u to 1980 Sep 28
> 01:00u; any time in that range, including 1980 Sep 28 00:00s, would indicate
> that Summer Time ends at 1980 Sep 28 01:00u, as specified in the EU rules. 
> Why one hour before the end of Summer Time was originally chosen certainly
> is puzzling.  Your suggestion to change the effective time to the time of
> the change, while not changing anything, does seem more logical.


>  However, I
> would suggest, even though WEST @ 01:00s and 01:00u are the same time, that
> it would be easier on the eyes and the heart if 01:00u, the convention in
> the EU rules, were used.

No objections here.  I get the same list of transitions either way.

Howard