Get Timezone based on longitude and latitude

[RicoCali]

Does anyone have a function that will give me Timezone based on Longitude and Latitude?

 

[SemperFiDownUnda]

I can almost, 99.9999%, guarentee that the answer is no.

This is because there is no formula for it. You'd need a database with spacitial extensions to do this effectively.

 

[SonOfEmidec1100]

Depends on what you mean by timezone, if you mean something basic then you can use the fact that every 15 degrees of longtitude = 1 hour in time difference. Eg Sydney is say 150W which equates to GMT + 10hrs, whereas 150E would be GMT-10hrs

Latitude does not affect the local time.

 

[SonOfEmidec1100]

I meant to add this link whilst not VB related may be of interest.

http://www-istp.gsfc.nasa.gov/stargaze/Slatlong.htm

 

[strongm]

>every 15 degrees of longtitude = 1 hour in time difference

However, RicoCali, bear in mind that real-world timezones don't actually follow this rule; there are plenty of exceptions and quirks. This is why SemperFi mentioned a database.

The maps shown on

http://www.travel.com.hk/region/timezone.htm

or

http://www.worldtimezone.com/

illustrate this quite nicely

 

[SemperFiDownUnda]

I live in Adelaide. We are +9.5 GMT, Factor in what locations have or do not have Day light saving it can become really hairy. There are 4 other time zones in the world that are offset by 1/2 hour.

 

[MichaelRed]

... and there are some which are offset by only 15 Min. Further, the "lines" do not (Always) go due north -South (the shifts in the partial increments are not East-West, but go along some 'diagional' line). I'm not sure that MOST of that matters for casual purposes, but if you are interested in 'Accuracy', it makes even a table insufficient, at least by itself.




MichaelRed
m.red@att.net

Searching for employment in all the wrong places

 

[strongm]

MapInfo have a product that stores the necessary information in a database that can be queried: Time Zones and Daylight Saving Time

 

[chiph]

Saudi Arabia officially uses "Solar Time", so in effect, an infinite number of timezones!

Just don't get me started on daylight savings time. One of my customers is in Indiana, and they don't change over at the same time as the rest of the USA. Truly difficult to set up conference calls with them. ;-)

Found the link to the MapInfo product:

http://www.mapinfo.com/products/Overview.cfm?productid=1719

Chip H.


If you want to get the best response to a question, please check out FAQ222-2244 first

 

[Golom]

chiph

> Saudi Arabia officially uses "Solar Time", so in effect, an infinite number of timezones!

Really? I lived there for 9 years and I never knew that ... though I have no doubt that it's true.