Calculating the Timezone

February 13, 2006 3:56 PM

I have GPS data associated with various measurements from around the world. This data also includes a UTC timestamp. I would like to display this timestamp converted to the local time where the measurement was taken, based on the GPS-reported latitude and longitude.

The simple 15 degree trick is not sufficient, I need the real, political time zone, not the ideal time zone, and the measurements move, so I can't just create a conversion table. It seems to me that I should be able to use something like mapserver along with a shapefile of time zone boundaries to solve this, but I have no experience with these tools. Surely I am not the first person to require this ability. Any ideas?

posted by Nothing to computers & internet (5 comments total)

I just did a quick Google and found a Web Service that gives you local time based on latitude and longitude. It looks you just need to grab the UTC offset and then add it to your own measurement.
posted by vacapinta at 4:07 PM on February 13, 2006

Can I ask what you googled for? That is just what I need and I thought I had tried every combination of search terms. In any case, thank you!
posted by Nothing at 4:15 PM on February 13, 2006

Fourth result in this Google search. I intentionally left off 'GPS' since thats a collection method rather than a data format.
posted by vacapinta at 4:26 PM on February 13, 2006

An alternative if you have ArcGIS at your disposal would be to do a spatial join of your point data to a vector layer that has the timezones in it.
posted by jduckles at 5:14 PM on February 13, 2006

Hey -- does anyone here know of a program that converts land survey (such as found in platt maps and on land surveys) coordinates into UTM? Perhaps you folks know of a program...Thanks...
posted by orlin at 8:14 AM on February 14, 2006