[R] time zones from longitude, latitude, and date

[David Winsemius]

On Sep 20, 2013, at 8:02 AM, carlisle thacker wrote:

> I have data that provide longitude, latitude, and local date and  
> time but
> no information about the corresponding time zone.  How to identify  
> the time
> zone so they can be converted to a common date/time?

Perhaps as an approximation you could divide the longitude by 360/24,  
truncate and subtract to get an estimated GMT. It really depends on  
your purposes, the encoding of "local time", need for accuracy, and  
perhaps further details regarding the data collection methods, none of  
which you have provided.

-- 

David Winsemius, MD
Alameda, CA, USA