The vast majority of the tz timezones are by construction matching a country, so little needs to be said about them: we equate them with the corresponding region in our fips10s data. As a consequence, the shapefiles presented here do not cover seas and oceans. Unfortunately, VMAP0 does not provide geometries for the territorial waters. While the boundaries in international waters are not difficult to construct, the boundaries of territorial waters are a completely different story, and are similar to the boundaries between countries. A captain can change ship's clocks any time after entering a new time zone midnight changes are common.” In international waters, time zone boundaries are meridians 15° apart, except that UTC−12 and UTC+12 are each 7.5° wide and are separated by the 180° meridian (not by the International Date Line, which is for land and territorial waters only). The tz database says: “A ship within the territorial waters of any nation uses that nation's time. This is a snaphsot of the zones (many of the smaller zones are not visible at this scale): The geometries are primarily derived from the fip10s data (itself derived from the VMAP0 data), augmented with data presented in the pages for the maps of the United States, Canada, Mexico, Russia and China. There is a companion map for the TZ timezones used in Antarctica stations. The geometries are either POLYGONs or MULTIPOLYGONs, and there is a single geometry for each TZ timezone. The tz_world_mp shapefile ( zip, sha1) captures the same boundaries. The geometries are all POLYGONs, and a TZ timezone will sometimes have multiple polygons. The tz_world shapefile ( zip, sha1) captures the boundaries of the TZ timezones across the world. A shapefile of the TZ timezones of the world tz_world, an /tz map A shapefile of the TZ timezones of the world This map is no longer maintained.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |