Frederik Ramm wrote:
HISTORY
of changes is already being logged ... so the information IS already in
the database ... it is how we access it that is the only technical
question.
Careful here. These are two totally different axes. We record the edit history -
when something was added, changed, deleted *in our database*. Recording when
something was creatd, modified, or razed *in the real world* would be completely
orthogonal to that.
You could enter the fact that something has been destroyed before you enter the
fact that something has been created, for example, or you could enter an earlier
"real life version" of something at a later date.
The point I was trying to make is that the 'volume' of data retained in the
database is not necessarily increased by adding additional historic information.
In years to come, the sort of historic material I am talking about would be part
of the EDIT history of the database. There is nothing orthogonal at all! One
just winds the mapping edit history back and can see the sort of changes I am
talking about. A large swage of UK information has simply been added over the
last 200 or so years, so the only additional data IS the 'start_date' when the
object came into existence. We need to add that for historic elements, but
anything created NOW may well become history in only a few years time. So the
only missing element is whether in future an object that becomes historic is
simply flagged as that, or 'deleted' but still exists in the edit history. In my
own databases nothing is deleted ... it simply gets flagged as to it's status
... in fact one has to hand edit the database to actually delete any data. In
OSM terms - we just look at the edit history for the same information.
--
Lester Caine - G8HFL
-----------------------------
Contact - http://lsces.co.uk/wiki/?page=contact
L.S.Caine Electronic Services - http://lsces.co.uk
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