For the exact details of the assignments, see the script in the ingredients. The next step is to perform an overlay of the two maps, to progressively assign a tzid to the geometries (identified by a combination of state, county and “modern” timezone, in accordance with the description above), and to finally dissolve on the tzid attribute. Layer, the change was to replace the common boundaries by the dataįrom the County Boundaries. Zone boundary departs from a county boundary. Layer, the only change was to add intermediate points where a time
Unfortunately, these two maps do not work well together: forĮxample, some common boundaries are not digitized in exactly the same Maps only captures the current time zones and does not include the the “County Boundaries, 2001” layer ( description,.The starting point is a couple of map layers from the National Atlas: The ingredients ( zip, sha1) contain a script to build the map, the modified sources. America/Boise: the part of Oregon legally in the Mountain Zone.America/North_Dakota/Beulah: North Dakota: Mercer county.America/North_Dakota/New_Salem: North Dakota: Morton county.America/North_Dakota/Center: North Dakota: Oliver county.America/Menominee: Dickinson, Gogebic, Iron and Menominee counties.
America/Kentucky/Monticello: Wayne county.America/Kentucky/Louisville: Jefferson county.America/Indiana/Indianapolis: rest of Indiana.America/Chicago: Gibson, Jasper, Lake, LaPorte, Newton, Porter, Posey, Spencer, Vanderburgh and Warrick counties.America/New_York: Dearborn and Ohio counties.America/Kentucky/Louisville: Clark, Floyd, and Harrison counties.America/Indiana/Vevay: Switzerland county.