[OHM] evolving road classifications & OHM

[Rob H Warren]

> From: suburbansilvervlogs+ohm.mailing.list at gmail.com
> To: historic at openstreetmap.org
> Subject: Re: [OHM] evolving road classifications & OHM
> Message-ID:
> 	<CABO5kczBtpMV-mWMNig7QJd8ZapepBRhP6B4gG56K=h0OeVE_A at mail.gmail.com>
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> 
> After perusing the wiki, I have located the proposed feature "date
> namespace", which (I think) seems to solve our problem.
> 
> https://wiki.openstreetmap.org/wiki/Proposed_features/Date_namespace
> 
> This is much more elegant then my own atrociously proposed syntax, and
> already has some uses in the main OSM database. Wondering what you think?
> 
> Cheers,
> Luke

Just be aware that ISO8601[1] (and it's W3 XML[2] subset) meant truncated representations to deal with recurring time intervals (eg: every 1st of the month) and not imprecision. 

Keeping in mind that there are few 'pure' ISO8601 parsers, most implementations interpret a partial timestamp by padding with zeros or ones, which means that "name:1933-1945 = Adolf-Hitler-Straße" will actually compute as "1933-01-01T00:00:00Z" to "1945-01-01T00:00:00Z" which is what people would likely think of as "name:1933-1944 = Adolf-Hitler-Straße".

If you are dealing with imprecision, it helps to think of the smallest period in which there is a 100% probability of the event having occurred and let someone else winnow it down later. If you are dealing with well known events, the use of historic era tags [3] will let someone else worry about it, or you could reference a peroid URI[4]  directly. 

best,
R


[1] https://www.w3.org/TR/xmlschema-2/#truncatedformats
[2] https://en.wikipedia.org/wiki/ISO_8601#Truncated_representations
[3] https://wiki.openstreetmap.org/wiki/Historic_Britain
[4] https://perio.do/technical-overview/