[tz] Dealing with Pre-1970 Data

Lester Caine lester at lsces.co.uk
Sun Sep 1 22:35:02 UTC 2013

Paul Eggert wrote:
>> Does the existing TZ database want to make provision to handle the results if people are prepared to put in the work needed?
> We are certainly interested in corrections to the
> existing pre-1970 data.  We've accepted those in
> the past and it shouldn't be too much work
> to maintain that data.
> If we're talking about adding the thousands of new zones
> that would be needed to support pre-1970 standard and
> daylight saving time, I'm not sure this list would be
> a good place to discuss each and every datum individually,
> though we could well be interested in incorporating
> the resulting batch of data as an optional extension
> to what we have now.  We're currently thinking about
> possible ways to support such an extension, with
> Zefram's code being the most recent proposal.

To be honest, I would just be looking to address the history of the existing 
entries. Since many of the reasons for database are modern inventions such as 
'daylight saving' ( which in itself is a fallacy - summer time is much more 
accurate ) I would not be expecting many if any additional 'zones'. The reason 
I've been 'hammering' the LMT aspect is because we know that at some point that 
will become prevalent, and there is certainly UK documentation for it, but I am 
quite happy that when the tz returned is 'LMT' then a 'local time offset' is 
required - based on longitude rather than a fixed 'zone' value. This would 
pre-date an 'LMTZ' offset where the zones of common time started to appear? Does 
that make sense of all the waffle I've been writing? It's starting to marry with 
the documents I've been gathering on top of the link you published to the UK 
research. But I don't know if it makes such sense world wide?

Lester Caine - G8HFL
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