I have investigated the timezones around 1970 on the http://www.astro.com/atlas site, and here are the results. I am attaching a GIF file of the map I have built based on this information. The red borders are the modern-time administrative borders, while the green lines are the timezone borders I have determined, note that some of them are partially hidden behind the red lines. There are no big surprises. Most timezones follow modern-day administrative boundaries, with the exceptions being Xinjiang, Xizang (Tibet), Qinghai, Gansu, Nei Mongol (Inner Mongolia) and Guangdong. There was an exception in Heliongjiang region on GMT+8.5 where the northern-most county Mohe is on GMT+8. A few other exceptions were two counties on the Sichuan side of the Xizang - Sichuan border, counties Dege and Baiyu which lies on the Sichuan side and are therefore supposed to be GMT+7, Xizang region being GMT+6, but Dege county is GMT+8 according to astro.com while Baiyu county is GMT+6 (could be true), for the moment I am assuming that those two counties are mistakes in the astro.com data. The biggest surprise was that region Guangdong were dived in 3 timezones, a south/west part on GMT+6 (counties Xuwen, Haikang, Suixi, Lianjiang, Zhanjiang, Wuchuan, Huazhou, Gaozhou, Maoming, Dianbai, Xinyi) a central part on GMT+7 (counties Yangchun, Yangjiang, Taishan, Kaiping, Xinxing, Luoding, Yu'nan, Yunfu, Taishan, Deqing and Enping) and a north/east part on GMT+8 with the rest of the counties. Zone Asia/Harbin on GMT+8.5: regions Heilongjiang (minus Mohe) and Jilin. Zone Asia/Shanghai on GMT+8: regions east Nei Mongol, Liaoning, Hebei + Beijing, Shanxi, Shandong, Henan, Jiangsu, Anhui, Shanghai, Zhejiang, Hubei, Hunan, Jiangxi, Fujian, north/east Guangdong and Mohe county of Heilongjiang. Zone Asia/Chongqing on GMT+7: regions west Nei Mongol, Ningxia, Shaanxi, east Gansu, west Qinghai, Sichuan, Guizhou, Guangxi, Yunnan, Hainan island and the central part of Guangdong province. Zone Asia/Urumqi on GMT+6: regions east Xinjiang, west Gansu (counties Dunhuang, Aksay, Anxi, Subei), west Qinghai, east Xizang (Tibet) and east Guangdong. Zone Asia/Kashgar on GMT+5: regions west Xinjiang, west Xizang. Regards, - Jesper Jesper Nørgaard Welen Email: jnorgard@Prodigy.Net.mx Project Leader (Líder de Proyecto) Software CIMMYT - Centro Internacional de Mejoramiento de Maíz y Trigo Dirección: CIMMYT Int. c/o Jesper Nørgaard Km. 45, Carretera México-Veracruz El Batán Texcoco, Edo. de México CP 56130 MEXICO Tel.: +52 (55) 58-04-20-04 ext. 1374 Fax: +52 (55) 58-04-75-58 Tel. Casa: 53-10-05-95 ó 53-10-97-78 Download the shareware program World Time Explorer, I made: http://www.worldtimeexplorer.com/index.html
Jesper Norgaard Welen <jnorgard@prodigy.net.mx> writes:
The biggest surprise was that region Guangdong were dived in 3 timezones, a south/west part on GMT+6 (counties Xuwen, Haikang, Suixi, Lianjiang, Zhanjiang, Wuchuan, Huazhou, Gaozhou, Maoming, Dianbai, Xinyi)
That is a surprise, and looking at your map it kind of sticks out like a sore thumb. Why would there have been a little island of GMT+6 in the sea of GMT+7, almost next to the GMT+8 region? Anyway, thanks very much for the info; I'll include it in the next proposed tz patch. Will you have a permanent URL for that map? If so, I'd like to include a URL as well.
It does look odd that there should be such a little island of GMT+6 in the sea of GMT+7, but if the decision about this was restricted to Guandong, then splitting this province in 3 parts the manner it is suggested by astro.com makes more sense. I don't know if there is any way to check if astro.com is right about this claim. The little map I sent anyone can put in your own web page(s) as you want, there is no copyright :-) If you rather want to point to it, like http://www.worldtimeexplorer.com/map/China1970.gif or something like that, I could put it up, but I haven't decided to put it up on a full web page with reference information etc. so I think a direct inclusion in your page(s) would be fine. Am I missing something? I wouldn't mind creating maps of other Olson db timezones if anyone is interested, as long as this is not too time-consuming. Regards, - Jesper -----Original Message----- From: Paul Eggert [mailto:eggert@cs.ucla.edu] Sent: Viernes, 14 de Julio de 2006 12:01 To: Jesper Norgaard Welen Cc: tz@lecserver.nci.nih.gov Subject: Re: Chinese timezones 1970 Jesper Norgaard Welen <jnorgard@prodigy.net.mx> writes:
The biggest surprise was that region Guangdong were dived in 3 timezones, a south/west part on GMT+6 (counties Xuwen, Haikang, Suixi, Lianjiang, Zhanjiang, Wuchuan, Huazhou, Gaozhou, Maoming, Dianbai, Xinyi)
That is a surprise, and looking at your map it kind of sticks out like a sore thumb. Why would there have been a little island of GMT+6 in the sea of GMT+7, almost next to the GMT+8 region? Anyway, thanks very much for the info; I'll include it in the next proposed tz patch. Will you have a permanent URL for that map? If so, I'd like to include a URL as well.
Jesper Norgaard Welen <jnorgard@prodigy.net.mx> writes:
If you rather want to point to it, like http://www.worldtimeexplorer.com/map/China1970.gif or something like that, I could put it up, but I haven't decided to put it up on a full web page with reference information etc. so I think a direct inclusion in your page(s) would be fine. Am I missing something?
Not really. I suppose I could put it up at twinsun.com.
I wouldn't mind creating maps of other Olson db timezones if anyone is interested, as long as this is not too time-consuming.
If you like doing that sort of thing I suspect it'd be appreciated. It is a FAQ. No doubt the geographic experts would want some data format other than pixels, but we can leave that up to you....
Jesper Norgaard Welen wrote:
I have investigated the timezones around 1970 on the http://www.astro.com/atlas site, and here are the results. I am attaching a GIF file of the map I have built based on this information.
Thanks to this data, I have put together a map in shapefile format for the timezone of China. It's available along with the recipe and necessary data files (including a mapping county->tz timezone and a concise description of the zones) at <http://efele.net/maps/tz/ch/>. Comments welcome, Eric.
Our group is relatively new to the tzdb and very new to GIS, but we do know that having timezone boundaries as shapefiles would be very useful. Is there a comprehensive source for timezones as shapefiles? It looks like a tremendous amount of work to do them--just wondering if it's all (or mostly) done already. Thanks, and Cheers! -- David Hancock | dhancock@arinc.com From: Eric Muller <emuller@adobe.com> Organization: Adobe Systems Incorporated Reply-To: <tz@elsie.nci.nih.gov> Date: Sat, 13 Sep 2008 19:10:24 -0700 To: <tz@lecserver.nci.nih.gov> Subject: Re: Chinese timezones 1970 Resent-From: <tz@elsie.nci.nih.gov> Resent-Date: Sat, 13 Sep 2008 22:10:33 -0400 (EDT) Jesper Norgaard Welen wrote:
I have investigated the timezones around 1970 on the http://www.astro.com/atlas site, and here are the results. I am attaching a GIF file of the map I have built based on this information.
Thanks to this data, I have put together a map in shapefile format for the timezone of China. It's available along with the recipe and necessary data files (including a mapping county->tz timezone and a concise description of the zones) at <http://efele.net/maps/tz/ch/>. Comments welcome, Eric.
Hancock, David (dhancock) wrote:
Our group is relatively new to the tzdb and very new to GIS, but we do know that having timezone boundaries as shapefiles would be very useful.
Is there a comprehensive source for timezones as shapefiles? It looks like a tremendous amount of work to do them--just wondering if it's all (or mostly) done already.
To my knowledge, there is not yet a publicly available shapefile that covers all the tz timezones, but there are shapefiles that cover "modern" time zones. As I alluded earlier, I am working on such a shapefile. There are three main difficulties: - understand what a tz timezone is a about (e.g. Asia/Samarkand vs. Asia/Tashkent) in logical terms, typically in terms of administrative divisions. - locate source GIS material for administrative divisions, with the appropriate traceability and distribution rights. Traceability is important: anybody can put together a shapefile, but it does not do much good if we don't know the quality of the data (whatever it may be), etc. And of course distribution rights probably matter to some users. - put everything together by a process that is automated enough so that new versions can be created easily, as new tz timezones are created, source material is corrected or the procedure itself is debugged. Fortunately, the VMAP0 polbnda layer provides most of the administrative divisions we need, is a known quantity and has the most liberal distribution rights I have found. I have already converted that layer to a usable shapefile (http://efele.net/maps/vmap0/polbnda/). I also established the mapping to FIPS 10-4 codes at http://efele.net/maps/fips-10/ (the VMAP0 data only has names, which are a pain to manipulate). That still leaves a few cases where we needs boundaries not present in VMAP0: - US: I have built a shapefile using various sources at http://efele.net/maps/tz/us/. - Canada: I have created a first cut that deals with all but a few little zones - China: I posted that one yesterday at http://efele.net/maps/tz/ch/ - Russia: I have a shapefile for that one, built from the map at http://wagda.lib.washington.edu/DATA/geography/world/russia/download.html - Brazil: that one is easy (using the VMAP0 layer for rivers, and a bit of geometry) - Australia: currently working on that one, does not seem too problematic - a few tz timezones are easy to describe in geometric terms (e.g. isolating the Kwajalein atoll) I also have a scheme to put everything back together with the VMAP0 data, and obtain a single shapefile for the world. As soon as I have Australia in good enough shape, I'll publish it, along with the procedure and all the source material I used; I hope to do that within a week or two. Of course, there will be some bugs, which I will be happy to fix. Eric.
participants (4)
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Eric Muller
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Hancock, David (dhancock)
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Jesper Norgaard Welen
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Paul Eggert