[LEAPSECS] Standards of time zones -Brooks Harris

[Brooks Harris]

Hi,

First, this is my first posting to your list, forgive me if the subject 
has been covered.

Second, I am a colleague Stephen Scott, also a new subscriber who posted 
a question earlier this week - (Subject: Local insertion of leap seconds).

My question is about the current state of standards concerning time zones.

Steve Allen's "Time Scales" 
http://www.ucolick.org/~sla/leapsecs/timescales.html 
<http://www.ucolick.org/%7Esla/leapsecs/timescales.html> is a tremendous 
help in many regards, and my thanks and appreciation for the work 
collected there. But it seems to side-step explanation of time zones, 
and its here I'm asking for guidance.

I fully understand time zone specifications are fractured. My objective 
is to determine what standards are most relevant currently, that is, 
what standards may be considered "in force". And where none exist, to 
state some sort of rules of "common use" or "common practice" without 
referring to the impossibly large collection of local jurisdictions and 
laws.

In particular -

A) "International Date Line", which is probably not standardized except 
by local decree, but the "180 degrees from the Greenwich meridian" has 
provenance back to the "International Meridian Conference of 1884" (not 
its proper name). Is there more modern standard that codifies this in 
any way?

B) The "International Meridian Conference of 1884" contains significant 
discussion of the idea "That these standard meridians should continue to 
be designated as even multiples of fifteen degrees from Greenwich", but 
there appears to be no explicit resolution of vote on the topic. I am 
unable to pick up the trail from there. There are many references in 
other conferences preceding and after the 1984 conference, but I have 
not discovered any official action on the subject. Again, is there any 
modern standard regarding that issue?

ISO 8601 describes using "offset from UTC" to indicate "time zone", but 
as far as I can tell it does not state either what a "time zone" may be 
or why an offset to a "time zone" from UTC might be useful. Is there any 
other standard that might describe this relation of UTC (zulu) to the 
"time zone" or "local time" more rigorously?

Of course the definition of "Greenwich meridian" has undergone many 
refinements and name changes since 1884. Claude Boucher describes the 
state of Formal international recognition of the International 
Terrestrial Reference System (ITRS)

https://www.google.com/#q=Formal+international+recognition+of+the+International+Terrestrial+Reference+System+(ITRS). 


Are there descriptions of "time zones" amongst the standards in this field?

And, of course, there is the subject of "Daylight Savings", apparently 
begun by George Vernon Hudson. Are there any modern standards or 
implementation guidance documents in force?

I'm aware of tz databse, of course, but here too there seems to be lack 
of clarity about what rules are being implemented, or, at least, I've 
found no consolidated statements of those rules there.

Comments and guidence welcomed, thanks very much,

-Brooks Harris