Time Zone Area Polygons

Rives McDow rmcdow at globaltimesystems.org
Thu Jul 6 09:19:53 UTC 2006

Dear All,

	I created a method of accessing the time zones of the world by  
longitude and latitude input a few years ago, and licensed it to  
Leighton Paul, who uses it in HourWorld (www.hourworld.com).  If you  
are on a Mac, you can download the program and take a look at it.  It  
allows the different timezones to be accessed with a resolution of  
about 100 feet at the equator, and corrects for daylight savings time  
automatically.  The code was written for use in a wrist watch, and is  
very compact, using quite a bit of preprocessing of the data.  The  
code and data take up about 120kb of space in memory in an 8 bit  
processor memory space, and about 276kb of space in a Mac memory  
space.  It includes all the boundaries of known time zones, collected  
from the local municipalities that are affected.  I believe there  
were about 180 or so of the unique polygons the last time I updated  
the library.

	I am not sure the best way to have this be used in this forum, as  
there are many issues involved in getting this into a form that can  
be easily maintained and is understandable by the user that just  
wants the functionality of GIS in a time zone related application.  I  
am working with Leighton and another programmer to see if we can  
address this in a way that would make the functionality available,  
but at this time, that would be by license, due to the expense of  
development and the patent rights associated with the methodology.   
If there is anyone in the list interested in pursuing this with me,  
please let me know.

	I am not trying to pitch this to this group, and tried a few years  
ago to bring this up as a spec that could be developed, with no  
success, due to the complex nature of GIS.  I have a rather arcane  
method of keeping the data and code current, and work closely with  
IATA and about 500 contacts worldwide to maintain the accuracy of the  
product.  It's called Global Time Systems (GTS®).  I hope that this  
can be of some help, and will be interested to work with anyone  
interested in pursuing this method of accessing local time.  I would  
just like to give a heads-up that it is not easily implemented or  
maintained without a full GIS application such as ArcInfo, and after  
in the GIS, is a bit clumsy to use unless a specialized application  
is written to create a lighter weight GIS for time specific uses  
only.  Hope this is of some help and interest.


Rives McDow

On Jun 30, 2006, at 12:35 AM, Paul Eggert wrote:

> "Olson, Arthur David \(NIH/NCI\) [E]" <olsona at dc37a.nci.nih.gov>  
> writes:
>> The only one that looks to have potential was the link to
>> [[]]
>> But that link keeps timing out.
> http://sarangworld.com/NMLUG/

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