all of China should be +0800, but some are showing up as +0600

[mikofski]

For example if I check Sichuan, China I get Asia/Urumqi at +0600, not China at +0800

from tzwhere import tzwhere
from datetime import datetime
import pytz

TZ = tzwhere.tzwhere(shapely=True, forceTZ=True)
JAN1 = datetime(2016,1,1)
JUN1 = datetime(2016,6,1)

# Sichuan, pvsim ID #1990489
tz.tzNameAt(29.45, 97.15)
pytz.timezone(tz.tzNameAt(29.45, 97.15))
sichuan = pytz.timezone(tz.tzNameAt(29.45, 97.15))
print sichuan
# Asia/Urumqi  <- this is the timezone

# method 1: strftime('%z'), this is used in HAL_db_migration
jan1 = sichuan.localize(JAN1)
tz_str = jan1.strftime('%z')
print tz_str
# '+0600'

see also mattbornski21

[cstich]

Can you elaborate why you think all of China should be +0800?
In our source data, China does have several timezones.

[mikofski]

I don't know the history, but here is my evidence:

• Wikipedia China Standard Time

  The time in China follows a single standard time offset of UTC+08:00 (eight hours ahead of Coordinated Universal Time), despite China spanning five geographical time zones. The official national standard time is called Beijing Time (Chinese: 北京时间) domestically and China Standard Time (CST) internationally.[citation needed] Daylight saving time has not been observed since 1991. [1]

• the tz_china map at efele.net/tz map is drawn mainly from a 1990 Chinese report, although later the timezone names for the 1990 polygons where supllimented in 2006 and 2009.

  All the geometries are the result of simple operations on China Administrative Regions GIS Data: 1:1M, County Level, 1990, created by Liu Chuang, Yao Xurong, William Laverly et al., published and disseminated by CIESIN, 1996.

  The assignment of TZ timezones is based on the description of the zones in 2009r, as well as messages exchanged on the tz mailing list in June-July 2006 (and in particular, the map sent by Jesper Nørgaard Welen on July 14). The description and the discussion explicitly mention the part of Guangdong which is surprisingly in the Asia/Urumqi timezone, and the map accurately reflects the description and discussion.

• One of our staff is a Chinese national who travels there frequently, and he categorically insists that all of China is +0800.

Sorry I can't be of more help - tzwhere is a great service. I have sent an email to Eric Muller.

[mikofski]

However, the IANA database says that there are 4 timezones!

[evansiroky]

Asia/Urumqi is a tricky one because technically both timezones are used in this area depending on what worldview you subscribe to.

[cstich]

@mikofski If you can report back what Eric Muller says that would be great.