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. Sincerely, Rives McDow On Jun 30, 2006, at 12:35 AM, Paul Eggert wrote:
"Olson, Arthur David \(NIH/NCI\) [E]" <olsona@dc37a.nci.nih.gov> writes:
The only one that looks to have potential was the link to [[ftp://69.17.46.170/downloads/free_world/WorldTZ.zip]] But that link keeps timing out.