[Tagging] demolished buildings, temporal component of data

Martin Koppenhoefer dieterdreist at gmail.com
Fri Apr 20 17:31:10 BST 2012


In some regions of the world OSM is already in a state where many of
the map modifications are not due to missing or wrong data, but result
from actual changes in the real world, e.g. a building gets
demolished.

Given that we store not only the actual state of the DB but also
record all kinds of changes that the mappers apply, I wonder if we
shouldn't agree on some formal mechanism to distinct the changes where
the map gets updated to the real world from those where the edit is
done to correct mapping errors, to increase the level of detail or to
store them for the first time.

Since the introduction of API 0.6 we have in theory one powerful tool
where this detail can already be associated to the edit: the changeset
comments. The only missing link for effective automated evaluation
would be an agreement on a formal way of storing information there
(and quite some discipline in structuring your edits and uploads ;-)
). E.g. we could use hashtags to distinguish free text from formal
comments ( e.g. #demolishion , #new_construction ,etc)

An alternative could be, e.g. for a building that was demolished, to
explicitly "map" this. Given an object tagged with building=yes we
could change the tag to building=demolished, upload to the server, and
in a second step delete the object and upload again. The deletion and
second upload could even be automated easily in the editors, if we
could agree on something like this.

As an advantage with the second method you would not need to structure
your edits and changesets in a special way, I'd expect to get more
reliable results and less oversight with this approach.

Is someone already using a scheme for this kind of information?

cheers,
Martin



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