[OSM-talk] Historical Data in OSM database

[M∡rtin Koppenhoefer]

2010/11/9 Peter Wendorff <wendorff at uni-paderborn.de>:
> If it would be as simple....
> I fear, it is not.


+1


> often jewish synagogues especially in Germany burned
> down by the Nazis, too few of them rebuild - like the one in Berlin
> Oranienburger Straße[1]).


that's actually a special case because it is one of the very few that
actually wasn't burnt down


> Big churches are often build over a time of several hundred years, changing
> shape and importance, even name - not to mention denomination or more than
> that religion) - think about Notre Dame in Paris [2] with a build time of
> nearly 200 years.


think of the cathedral at Cologne, built for over 600 years...
These are not exceptions, almost every house dating back to the
middleages and remaining till today was continuously transformed
through the ages. Most of this is not suitable for out database,
because it would require a much higher level of detail and probably
3D-geometry.


> That in mind as examples - far from complete - neither start_date nor
> start_date and end_date are enough to describe historical data in a good way
> to be useful.


depends how you apply it, but yes, it is not sufficient for a higher
level of detail.

I think that historic mapping is less interesting/possible/feasible
for the past, but it is very interesting for the future: as someone
mentioned above, currently we have no way (besides textual changeset
comments) to denote if a feature is changed or deleted because it was
bad (wrong) or because the actual feature has changed. If you look in
well mapped areas like big parts of Germany, we are about to come to a
certain point of "completeness". In these areas it would be quite
interesting (given that our project will endure ;-) ) to actually tag
things that change or get destructed with appropriate
(changeset-)tags/attributes. This way we could make better use of the
history information already existing in our db and have "historical"
mapping from now to the future.

Cheers,
Martin