FW: quality of historical zone information
Alois Treindl is not on the time zone mailing list; direct replies appropriately. --ado -----Original Message----- From: Alois Treindl [mailto:alois@astro.ch] Sent: Sunday, January 28, 2001 11:11 AM To: tz@elsie.nci.nih.gov Subject: quality of historical zone information Hi 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 essential. 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 areas. 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 in mid-2002. 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. Best regards || Alois Treindl, Astrodienst AG, mailto:alois@astro.com || Zollikon/Zurich, Switzerland || Free astrological charts at http://www.astro.com/ || SWISS EPHEMERIS Free Edition at http://www.astro.com/swisseph/
Alois Treindl wrote:
Defining more zones will not be enough. it must be possible to associate every populated place with the right zone.
That's a requirement for my work, too. I have been working in the field of logistics. To track shipments, I need to be able to convert from local time to UTC, based on location. That means I have to know the historical sequence of UTC offsets for each possible location. The difference between my application and astrology is that I'm concerned with a much narrower range of dates: typically from today minus three months to today plus three months, although for archival purposes I may want to look back several years. If the membership of the tz list, or any other group, wants to undertake to create and maintain a more complete tz archive that would do justice to the geographical aspect, I have a few principles to suggest. Too much work is involved to expect any one person, especially a volunteer, to do it all. There's a natural way to subdivide it: by countries. In general, time zones are determined by legislation which applies throughout a jurisdiction, almost always a whole country. In many cases, a volunteer could take responsibility for several countries or a whole region. On the other hand, a country with a very complex time zone history, such as the United States, might be divided up among several volunteers. Ideally, each volunteer would be acquainted with the languages and culture of the region he or she is responsible for. Uniform guidelines should be drawn up, covering things like database design, data authentication, and update notification. Database design: The current tz archive has an implicit database design, which is implemented in various Posix-compliant systems. This existing design is inadequate for some purposes. For example, Brazil is divided into areas that observe four different standard times. The information about which state is in each area is hidden in the comments. If a new database design allows the geographical component to be represented, Posix systems should be supported as a legacy. This might be done by taking a slice or subset of the data. Other systems might choose to take a different slice, in order to tailor the data to their specific requirements and save on storage. A logistics application might select only post-1996 data, having no need to refer further back than that. Data authentication: the data in the existing tz archive were acquired from several sources. They're cited in the comments. They include Shanks, Whitman, IATA, and personal communications from a number of Time Zone Caballeros. None of these are really primary sources. Primary sources include laws, acts, and decrees reported in the Congressional Record, Hansard, etc., and newspaper reports of actual time zone implementation. We do have some primary sources, but they don't cover the whole world. When several sources disagree (and we don't have a primary source), someone like Paul Eggert decides which is the most reliable, and explain his decision in the comments. As new sources become available, some of the old decisions may have to be reconsidered. What we need is a file containing every available document that has clues to historical time zone data. This file could be partitioned by country or region, so that each time zone volunteer saves only those documents pertaining to his or her specific area. Guidelines should cover criteria for selecting the most reliable information from a set of documents, as well as the maintenance, back-up, and public availability of the source material. Update notification: Some updates to the expanded tz archive would be to correct old errors. Others would be to extend time zone rules further into the future. Currently, all updates to the tz archive affect all users, and are reported to the tz mailing list. Would this still be sufficient? It would be a great help to maintain a Web site that displays all the tz archive data in a format easily understood by casual users. For one thing, more people would be able to find mistakes in the data and send in corrections. Perhaps Web pages could be automatically generated by applying a transformation to the archive. The work I've described above would be a valuable service to the Internet community. Is there some way to finance it? For example, could certain beneficiaries be persuaded to subsidize it? Could advertising be sold on the Web site? If so, the volunteers could be paid, and the archive could be more effectively improved. Yours, Gwillim Law
This is a generic issue in many standards. For some "three months", see below is "historical". For others, the past year is contemporary. Working in Open-edi standardization (JTC1/SC32/WG1), security services(JTC1/SC27) as well as the area of geomatics (ISO TC 211) from an e-commerce, e-business, e-gov't, etc. standardization perspective, I would welcome input, ideas, etc. on some common agreement as to what we mean by "contemporary", "historical", "archival", etc.. Being involved in logistics, I not only have to know and record the local time/date to UTC (or vice-versa), I also have to be able to support "records retention" requirements of the jurisdictions in which I do business. Working in a complete electronic/digital mode, I keep records of completed business transactions only as long as I am legally required too, (e.g. via an automated time zone driven deletion routines). Can we, should combine our needs, efforts here into a new standard? Gwillim is absolutely right when he says that this is too much work for any one person (no matter how expert). looking forward to feedback, ideas - Jake Knoppers (Canada)
-----Original Message----- From: Gwillim Law [mailto:gwil@mindspring.com] Sent: January 29, 2001 1:20 PM To: tz (E-mail); alois@astro.ch Subject: Re: quality of historical zone information
Alois Treindl wrote:
Defining more zones will not be enough. it must be possible to associate every populated place with the right zone.
That's a requirement for my work, too. I have been working in the field of logistics. To track shipments, I need to be able to convert from local time to UTC, based on location. That means I have to know the historical sequence of UTC offsets for each possible location. The difference between my application and astrology is that I'm concerned with a much narrower range of dates: typically from today minus three months to today plus three months, although for archival purposes I may want to look back several years.
If the membership of the tz list, or any other group, wants to undertake to create and maintain a more complete tz archive that would do justice to the geographical aspect, I have a few principles to suggest.
Too much work is involved to expect any one person, especially a volunteer, to do it all. There's a natural way to subdivide it: by countries. In general, time zones are determined by legislation which applies throughout a jurisdiction, almost always a whole country. In many cases, a volunteer could take responsibility for several countries or a whole region. On the other hand, a country with a very complex time zone history, such as the United States, might be divided up among several volunteers. Ideally, each volunteer would be acquainted with the languages and culture of the region he or she is responsible for. Uniform guidelines should be drawn up, covering things like database design, data authentication, and update notification.
Database design: The current tz archive has an implicit database design, which is implemented in various Posix-compliant systems. This existing design is inadequate for some purposes. For example, Brazil is divided into areas that observe four different standard times. The information about which state is in each area is hidden in the comments. If a new database design allows the geographical component to be represented, Posix systems should be supported as a legacy. This might be done by taking a slice or subset of the data. Other systems might choose to take a different slice, in order to tailor the data to their specific requirements and save on storage. A logistics application might select only post-1996 data, having no need to refer further back than that.
Data authentication: the data in the existing tz archive were acquired from several sources. They're cited in the comments. They include Shanks, Whitman, IATA, and personal communications from a number of Time Zone Caballeros. None of these are really primary sources. Primary sources include laws, acts, and decrees reported in the Congressional Record, Hansard, etc., and newspaper reports of actual time zone implementation. We do have some primary sources, but they don't cover the whole world. When several sources disagree (and we don't have a primary source), someone like Paul Eggert decides which is the most reliable, and explain his decision in the comments. As new sources become available, some of the old decisions may have to be reconsidered. What we need is a file containing every available document that has clues to historical time zone data. This file could be partitioned by country or region, so that each time zone volunteer saves only those documents pertaining to his or her specific area. Guidelines should cover criteria for selecting the most reliable information from a set of documents, as well as the maintenance, back-up, and public availability of the source material.
Update notification: Some updates to the expanded tz archive would be to correct old errors. Others would be to extend time zone rules further into the future. Currently, all updates to the tz archive affect all users, and are reported to the tz mailing list. Would this still be sufficient? It would be a great help to maintain a Web site that displays all the tz archive data in a format easily understood by casual users. For one thing, more people would be able to find mistakes in the data and send in corrections. Perhaps Web pages could be automatically generated by applying a transformation to the archive.
The work I've described above would be a valuable service to the Internet community. Is there some way to finance it? For example, could certain beneficiaries be persuaded to subsidize it? Could advertising be sold on the Web site? If so, the volunteers could be paid, and the archive could be more effectively improved.
Yours, Gwillim Law
On Mon, 29 Jan 2001, Gwillim Law wrote:
Too much work is involved to expect any one person, especially a volunteer, to do it all. There's a natural way to subdivide it: by countries. In general, time zones are determined by legislation which applies throughout a jurisdiction, almost always a whole country. In many cases, a volunteer could take responsibility for several countries or a whole region. On the other hand, a country with a very complex time zone history, such as the United States, might be divided up among several volunteers. Ideally, each volunteer would be acquainted with the languages and culture of the region he or she is responsible for. Uniform guidelines should be drawn up, covering things like database design, data authentication, and update notification.
We also should be working with Shanks, ACS, le Corre etc. on such a common database, rather than irregularly taking updates from each other.
may have to be reconsidered. What we need is a file containing every available document that has clues to historical time zone data. This file could be partitioned by country or region, so that each time zone volunteer saves only those documents pertaining to his or her specific area.
A paper or an electronic file? My file of papers relating to time zone history in the UK is about four centimetres thick - and this is mostly just copies of the relevant laws. A file that also included all relevant extracts from Hansard, etc., would be somewhat thicker; and if all the archive material in the Public Record Office were added - providing much of the colour behind the bare details of the dates and times (and also including miscellaneous papers relating to other European countries) then there could be a metre or more thickness of papers. Such a collection of "every available document that has clues" seems rather ambitious. -- Joseph S. Myers jsm28@cam.ac.uk
<<On Mon, 29 Jan 2001 19:23:04 +0000 (GMT), "Joseph S. Myers" <jsm28@cam.ac.uk> said:
A paper or an electronic file? My file of papers relating to time zone history in the UK is about four centimetres thick[.] [...] [T]here could be a metre or more thickness of papers.
This seems like a rather specialized field, but perhaps it would be worth the effort to find a research library somewhere which would be willing to host such a collection. I would be happy to feel out the MIT Libraries as to whether they would be willing to do so. -GAWollman
On Mon, 29 Jan 2001, Garrett Wollman wrote:
This seems like a rather specialized field, but perhaps it would be worth the effort to find a research library somewhere which would be willing to host such a collection. I would be happy to feel out the MIT Libraries as to whether they would be willing to do so.
I'd rather doubt that a research library would want to host such a collection of copies of source material found in various public archives. Listing the available source material, and producing abstracts for it, might be marginally practicable given enough volunteers. Collecting in one place copies of the source material from 200 countries is both much less practicable and of limited utility until automatic searching of manuscript material is much more advanced than at present. -- Joseph S. Myers jsm28@cam.ac.uk
From: Alois Treindl [mailto:alois@astro.ch] Sent: Sunday, January 28, 2001 11:11 AM
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.
That's too bad. Their database is the best resource I know of for this area.
Defining more zones will not be enough. it must be possible to associate every populated place with the right zone.
Yes. We could have a geographical polygon associated with each zone. Ideally there should be justification for why the polygon is the way it is. The best free work that I know of in this area the time zone map information published by Manifold.net. The USGS also has some data for the US. I plan to add links for this in my next proposed tz patch. However, these maps cover only current data; they do not address historical issues. For more, please see: http://www.manifold.net/download/freemaps.html http://software.geocomm.com/data/intl_timezones.html http://www.nationalatlas.gov/timeznm.html
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 in mid-2002.
That's good news.
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.
Not yet, but we'd love to have your help.
] Alois Treindl is not on the time zone mailing list; direct replies ] appropriately. ] ] --ado ] ] -----Original Message----- ] From: Alois Treindl [mailto:alois@astro.ch] ] Sent: Sunday, January 28, 2001 11:11 AM ] To: tz@elsie.nci.nih.gov ] Subject: quality of historical zone information ] ] ] Hi ] ] 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 ] essential. ] ] 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. Please bear in mind the following extract from the "Theory" file :- If all the clocks in a country's region have agreed since 1970, don't bother to include more than one location even if subregions' clocks disagreed before 1970. Otherwise these tables would become annoyingly large. __________________________________________________________________________ David Keegel <djk@cyber.com.au> URL: http://www.cyber.com.au/users/djk/ Cybersource P/L: Unix Systems Administration and TCP/IP network management
participants (7)
-
David Keegel -
Garrett Wollman -
Gwillim Law -
INFOMAN Inc. -
Joseph S. Myers -
Olson, Arthur David (NCI) -
Paul Eggert