LMT information, geographics of Antarctica bases

Oscar van Vlijmen ovv at hetnet.nl
Wed Mar 23 20:09:21 UTC 2005

> From: Paul Eggert

>> It is not always true that the _last_ LMT entry is correct in the sense of
>> true solar LMT.
> That is because "LMT" (like all such abbreviations) is ambiguous.

It would have been nice if the tz database had unambiguous information.
I don't like XML (too much overhead, interpreting data means more
programming, other factors), but in an XMLized database one could inspect
tags that unambiguously define data as such and such.

The results of the current discussion could be used in a far future if and
when the tz database gets converted.

A similar type of difficulty was discussed previously (around 2004-05-17).
For instance,

# Korea (North and South)
Rule    ROK    1987    1988    -    Oct    Sun<=14    0:00    0    S
Zone    Asia/Seoul    8:27:52    -    LMT    1890
            9:00    ROK    K%sT

This posed no problem for the tz programs, so nothing was changed.
On the other hand, if you convert the database (semi-)manually, you can only
find out by meditating deep and hard that South Korea currently does not
observe DST, although the Zone information says Rule ROK is in effect.
Checking all this is a lot of work for all the 200+ entries, which as I have
experienced, leads easily to errors.

> From: David Keegel

> If you were trying to get a table/database of city->LMT values for
> the present day, I doubt that the tz database would be a good source
> for that.  For a start it only includes a limited set of cities

True. NGA's Geonet name server is a better source of location data (lat/lon)
for millions of places. For the USA: GNIS/USGS.
[The download pages:
for USA & Antarctica places:
and for other places:
Don't download the 1 in all file, your word processor may choke to death!]
But I did hope it were possible to extract LMT information _quickly_ from
the tz database, just to get a rough idea of the discrepancy between solar
time and zone time.

Oscar van Vlijmen

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