[tz] Request for Change of Time Zone Name from Asia/Ho_Chi_Minh to Asia/Ha_Noi

[Đoàn Trần Công Danh]

On 2024-07-03 18:54:14+0100, Ian Abbott via tz <tz at iana.org> wrote:
> On 03/07/2024 08:11, viet le via tz wrote:
> > I am writing to formally request a change in the naming of the time
> > zone for Viet Nam in your database. Currently, the time zone is listed
> > as "Asia/Ho_Chi_Minh." However, I would like to propose that this be
> > updated to "Asia/Ha_Noi" to reflect the official and more widely
> > recognized name of the time zone.
> 
> There is already a timezone identifier "Asia/Hanoi" but it is defined in the
> "backzone" file because it has been the same time as "Asia/Ho_Chi_Minh"
> since 1970. It may or may not be installed on various operating systems.

Asia/Hanoi is back-linked to Asia/Bangkok because Hanoi is in the
GMT+7 timezone from 1968, which is matched with Asia/Bangkok which is
this project convention.

Asia/Ho_Chi_Minh (or Asia/Saigon for that matter), has a different
time system. Asia/Ho_Chi_Minh is in GMT+8 until 1976, and switch to
GMT+7 that year.

So no! Asia/Ho_Chi_Minh != Asia/Hanoi, and we can't rename
Asia/Ho_Chi_Minh to Asia/Hanoi because, the time information there is
not the the time information of Hanoi, in whatever context.

> 
> > Hà Nội, as the capital city of Viet Nam, is the administrative and
> > political center of the country. It holds significant historical,
> > cultural, and socio-economic importance. Consequently, using Hà Nội as
> > the reference point for the country's time zone would be more
> > appropriate and align with international standards and practices.
> 
> The timezone identifier string for a region is based on the most populous
> city in the region, not on political centers.  For example, the TZ database
> contains "Asia/Shanghai" (rather than the capital city "Asia/Beijing") for
> this reason.  This policy is described in the TZ "Theory" document:
> https://ftp.iana.org/tz/theory.html

Unlike the case of Beijing (Peking) or Shanghai, the case of Hanoi and
Ho Chi Minh is different.  Which city is bigger, regardless of Hanoi or
Ho Chi Minh, doesn't matter! Because those 2 cities, (and their
covered region North-South of Vietnam) have different timezone system.

So no!, we can't rename Asia/Ho_Chi_Minh to Asia/Hanoi, and we can't
remove Asia/Ho_Chi_Minh, because Asia/Ho_Chi_Minh has an unique
timezone history.

-- 
Danh