Use geofield to auto set time zone field

Looking at the issue queue, you may need to apply for (co)maintainership (http://drupal.org/node/251466) as the original author has not done anything for years. eg #1932968: Set default value to user's timezone

I'm interested in this. There are already some other options out there. I've browsed through them.
Some are javascript-solutions. I don't think we need that.

The Google Time Zone API
http://drupal.org/project/timezone_detect
http://drupal.org/project/timezone_picker
http://drupal.org/project/autotimezone (but changes the server, not a node-at-hand)
misc/timezone.js (Drupal core's own timezone determination on user login, including a 'system/timezone callback ')
#1030212: Add identification of user's timezone
#968272: Setting a timezone field on a node
#918610: Add a function to return the PHP timezone name for a given zipcode (US only)
PHP: http://www.php.net/manual/en/function.timezone-location-get.php

- Geofield would only be the first of several sources: location, IP-address are the next in line.
- Will this patch fill the 'core' user time zone, too?

http://drupal.org/sandbox/xandeadx/1999792

If you (@xandeadx) agree I could merge your sandbox module as a submodule of the tzfield module.

Any ideas are welcome @johnv just open an issue and post your patch.

I don't mind

Merged your sandbox module AS IS with this module.
Thank you for your time and efforts.