[tz] Dealing with Pre-1970 Data

Lester Caine lester at lsces.co.uk
Sun Sep 1 13:16:02 UTC 2013

Zefram wrote:
>>                                          but you have already made
>> >assumptions in that script which is the point here.
>> >Silly little things like is 7.5 degrees included in the first or
>> >second zone of a simple grid.
> That's not local mean time, as we understand it.  If you want the strict
> hour-interval time zones (which is what gives you 7.5 degree edge cases),
> round the LMT offset to the nearest hour.

That is just a different edge case ;) Is the half hour rounded up or down.
I've been working on cross database compatibility for a long time. Presented 
papers on that back in the early 80's. You put exactly the same data into two 
different databases and apply the same SQL scripts to produce what can be vastly 
different results. Conversions reducing resolution in data, such as the 
longitude fine detail and so on. Producing formulas that give a consistent 
result is not quite so simple as you are assuming. Even following the available 
standards still produces inconsistent results.

Lester Caine - G8HFL
Contact - http://lsces.co.uk/wiki/?page=contact
L.S.Caine Electronic Services - http://lsces.co.uk
EnquirySolve - http://enquirysolve.com/
Model Engineers Digital Workshop - http://medw.co.uk
Rainbow Digital Media - http://rainbowdigitalmedia.co.uk

More information about the tz mailing list