Geographical boundaries for Canadian time zones (was: Geographical boundaries for the continental US tz zones)
Chris.Walton at telus.com
Fri Jun 1 16:47:15 UTC 2007
I can not help you with the time zone boundaries within the Unites States.
However, I wanted to let you know that I created a KML time zone map for Canada.
It may give you some ideas of what you can do with KML.
The file is in KMZ (compressed KML) format; it is 682kB in size and should open in in Google Earth.
Use the radio buttons to select between "winter", "summer", and "outlines" views.
In the "outlines" view, hover your mouse above the center of an outline to highlight it and make a name appear. Click in the center of a highlighted outline to view more information.
Also, you should have a look at Jesper's WTE program. Jesper has put a great deal of effort into making his maps as accurate as possible.
By the way, the links you provided for the US time zone areas <http://efele.net/timeznp020.zip> seem to have lots of points with many "significant digits" giving the illusion of accuracy. Unfortunately your data shows many sections of US/Canada border to be about 200 meters north of where it is
supposed to be.
Is this a sign that the US is trying to encroach on Canada? Should the Canadian military be put on alert?
I should also mention that the Google Earth yellow borders should not be used as references; they are notoriously inaccurate; I usually turn them off.
If you are reading this and you get a chance to open my latest canada.kmz file, you will notice that there are lots of new islands that were not shown last time I sent you a copy of the file.
>From: Eric Muller [mailto:emuller at adobe.com]
>Sent: May 31, 2007 1:55 AM
>To: tz at lecserver.nci.nih.gov
>Subject: Geographical boundaries for the continental US tz zones
>I am trying to figure out the geographical extent of the 19 continental US timezones
defined by tz. Because my goal is ultimately to create a freely >available digital map, I would like to get definitions in terms existing, freely available digital maps, and the ones at nationalatlas.gov seem >appropriate. Specifically, I plan to use countyp020 (county boundaries 2001), statesp020
(states) and timeznp020 (time zones) [see below for more details on those maps]. I tried to translate the comments in the "northamerica" file in terms of operations on the elements of those three maps, but I have a few questions/comments.
More information about the tz