Last data update: November 10, 2009
Last page update: June 25, 2012
The tz_china shapefile captures the TZ timezones of China, as of TZ 2012c.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.
This is a snapshot of the shapefile, with province boundaries:
This is a concise description of the zones, using the counties as they existed on December 30, 1990. The names are those in the China Dimensions data.
The zip of the ingredients contains a script to build the map from the source as well as cd2tz.csv which lists all the counties, with their name, code, province name, and TZ id.The starting map is the tbd90 layer of the China Dimensions data collection. (Note that the pbd90 layer is not just a dissolution of the tbd90 layer.)
The source data is converted to a shapefile using the ESRI import71 utility, and reprojected from the original projection/datum to WGS 84 using ogr2ogr.
The remaining steps are simply to join the tbd90 layer and cd2tz.csv, and to dissolve the result on the tzid attribute.
To the extent possible under law, Eric Muller has waived all copyright and related or neighboring rights to the efele.net/tz maps (comprising the shapefiles, the web pages describing them and the scripts and data used to build them). This work is published from the United States of America.
Note that this does not affect the rights others may have. I am not qualified to determine whether such rights exist.
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