quality of historical zone information
alois at astro.ch
Sun Jan 28 16:10:09 UTC 2001
my company is an astrological computer service, and as you certainly
know, astrologers are the only group of people for whom precise
timezone information for any place, and any historical time is really
This is also why Thomas Shanks had created the International and
American atlas. Tom is long gone from ACS, and they no longer maintain
their database properly.
Your site has become the essential source on timezone information.
However, for historical work your data are insufficient in many
For example in Germany, there must be about 20 zones differentiated
which have had a different timezoen history since the introduction
of standard time.
Th tz database has only a single zone info for Germany.
For many other countries the same is true, e.g. for France, where
there is a complicated historical pattern, especially during the
years of the World War II and german occupation.
Many US states have a very complex timezone history, and for some
states several hundreds of 'zones' will be needed to reflect
these data precisely.
Defining more zones will not be enough.
it must be possible to associate every populated place with the right
zone. For example in the case of Germany, each village or city must be
associated with one of the zones. Current organisational units, like
districts or 'Laender' are not sufficient for that, because some towns
have changed this association occasionally in the past, i.e. have
changed the 'land' or disctrict to which they belong.
I would like to see the tz-database become THE reference source for
this kind of information, but it is a long path of work. I might be able
to contribute to this efffort, particularily after my scheduled retirement
I would like to know whether there are any plans of a systematic nature
to improve the quality of historical work in the TZ database.
|| Alois Treindl, Astrodienst AG, mailto:alois at astro.com
|| Zollikon/Zurich, Switzerland
|| Free astrological charts at http://www.astro.com/
|| SWISS EPHEMERIS Free Edition at http://www.astro.com/swisseph/
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