[OSM-talk] Id stability

[Gregor Horvath]

Hi,

Am Mon, 01 Aug 2011 09:21:44 +0200
schrieb Frederik Ramm <frederik at remote.org>:
 
> That was me. There are a number of other reasons why IDs could
> "break". One is the expansion of POI nodes into buildings that Toby
> mentioned. Another is the splitting of ways (old ID would then point
> to only half) or merging (old ID would become invalid in 50% of
> cases). Same with the re-structuring of relations or the re-mapping
> of stuff in the course of the license change.

It is a logically inaccurate to delete an ID in such cases.
What you actually logically do is replacing an ID, or creating an alias.
The problem is there is no semantic in OSM data to express such a move
operation. Deleting is the wrong one. Deleting means a destroyed house
or physically removed street and in this case it is logically correct
that the ID is gone.

So my proposal is to describe move operations in OSM data.
For example: Instead of deleting, all tags of the object or removed and
a "alias_for" "joined_with" "splitted_to" tag(s) which points
to the new correct node(s) ID is inserted to the old node .

Than external programs can find the proper one with the old id and the
OSM data gets richer and more accurate.

--
Greg