[OHM] Open Historical map

[PauLL170]

Hi,

I understand that there is the need to discuss the time format, but to be
honest that was not my first intention. Now, the chances for the ".."
format to be implemented in the first version of the time slider decreases
and most of the objects in Germersheim won't be displayed then.

But of course, i'm inclined to discuss about it. However, I will try to
argue for the ".."-format, because I have not seen a better (relatively
easy (only one, respectively two tags etc.)) way and it is manifested in
the wiki and hence often used (e.g. by me).

1.) regarding individual dates ("in the reign of Queen Elizabeth,
inter-war, 1970s, 1970, May 1971 etc") we will have to stress, that the
".."-format should be used as soon as it is possible (at least in OHM):
Queen Elizabeth: start_date = 1558..1603-03-24; 1970s: start_date =
1970-01-01..1979-12-31; May 1971: start_date = 1971-05-01..1971-05-31.
Theoretically we also should insist on using 1970-01-01..1970-12-31 instead
of 1970, but that's not realistic, because it is too easy just to write
"1970" ;-)

2.) When users observe this, the only thing the time slider has to do is
convert (internal) a year into a range: start_date = 1558 is processed as
1558-01-01..1558-12-31 respectively start_date = 1558..1603-03-24 is
processed as 1558-01-01..1603-03-24

3.) regarding vague values like ~1970: I think, that is not a matter of the
format foremost. In a "radical" view, these values can't be displayed,
because we don't know anything technically (but probabilities). But since
not everything is about time sliders and rendering I appreciate better ways
to express it (EDTF etc.).

4.) Changing features of a certain object is indeed needed to be discussed,
because the date namespace format (
https://wiki.openstreetmap.org/wiki/Proposed_features/Date_namespace) may
has some disadvantages, but it neither does compulsively affect the format
of the start_date. But I admit, that this is a very difficult thing,
especially when the exact dates of these changed features are unknown (e.
g. a road which was renamed at an uncertain date). A first solution could
be to draw a new object for it as often as possible.

To summarize: I know, that there a some questionabilites regarding the
".."-format and I will accept a better suggestion - and I am looking
forward to continue the discussion here - but we should ensure that we
agree on one format and implement it in the time slider at the end of the
day as long as we don't want to discuss again in two years without having
moved forward.

Best regards,
Paul
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.openstreetmap.org/pipermail/historic/attachments/20180508/c500a71c/attachment.html>