[tz] About the core city of a tz region

David Patte ₯ dpatte at relativedata.com
Mon Jul 20 17:27:22 UTC 2015

I'm thinking in particular of Montreal vs Toronto.

Montreal is 150 years older than Toronto, and was much larger than 
Toronto in 1970 according to any census I have seen.

When Toronto overtook the population of Montreal is debatable, but one 
might say it was after 2000 when an amalgamation of Toronto with 
surrounding cities it grew into, caused its population to nearly double. 
The original core city of Toronto is still likely smaller than Montreal.

But if you count the metro area and all suburbs than clearly Toronto is 
now dramatically larger especially in the last 10 years. By the most 
inclusive counting method I have seen (though not the most common 
counting method), the area in and around Toronto is currently over 6 
million (more than Chicago!), whereas the equivalent area in and around 
Montreal is currently only about 4 million.

But the reason I mention historical data is that in 1970, and maybe much 
more recently, Montreal was clearly the larger city by a factor of 1.5, 
and this discrepancy increases backwards over time. Pre1970 timezones 
rules affected more people living in Montreal at the time, than lived in 
Toronto at the time.

On 2015-07-20 02:23, Robert Elz wrote:
>      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


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