timezone lookup based on timestamp and geo coordinates - creation of mysql database

The task is simply to setup a number of mysql database tabels that I can use to query the offset from UTC time based on input of latitude and longitude coordinates along with a timestamp. Daylight saving time should be taken into account. I found some information here: [login to view URL] But what I'm missing to make that work are the timezone polygons, but I did find some information about that here: [login to view URL] You don't necessarly need to use the above sources. You have to supply a working package of mysql dumpfile along with an example query to get the timezoneoffset of a certain location at a certain time. I need to get this to work asap.