[tz] About the core city of a tz region

[Robert Elz]

    Date:        Mon, 20 Jul 2015 00:10:56 -0400
    From:        =?UTF-8?B?RGF2aWQgUGF0dGUg4oKv?= <dpatte at relativedata.com>
    Message-ID:  <55AC74D0.3070105 at relativedata.com>

  | Is the core city in a region always the most populous city in the tz region?

Generally, as best we can determine it (where "city" includes the metropolitan
area surrounding what is technically the city, in cases where that is
appropriate.)

  | And what is done if a smaller city's population overtakes the named 
  | city? Is the zone renamed?

It could be - but that is likely to happen only if the "overtakes" is
dramatic, and is likely to remain that way (and definitely not if in
order to obtain that result the numbers need to be fudged - such as
excluding half of what most people would consider to be the population of
one of the cities based upon some bureaucratic mumbo jumbo).

If it does happen, the old name is retained (as a Link) of course, so
anyone used to it can continue using the earlier name.

  | Also, since historical data (pre-1970) is now maintained only for the 
  | named city in a region, does it not make sense to use the population as 
  | of 1970, since the historical records actually affected more people at 
  | that time?

I can't begin to imagine the connection between that (first) "since" and the
conclusion suggested, nor do I see how the second reason given is either
related, or even correct.

The populations of the various cities are considered as of the time that
the zone is created (it is entirely possible a new city could be built,
and given a new set of timezone rules, and hence a new timezone, where
considering populations of nearby villages from 1970 would be nonsensical).

For most of our zones the decision was made closer to 1970, than to now
of course.

kre