[OSM-talk] Tagging OSM objects with UUIDs

Frederik Ramm frederik at remote.org
Mon Jun 7 10:01:54 BST 2010


John Smith wrote:
> I think you have misunderstood or at least not comprehended the
> potential for being able to easily share the same ID with other
> databases without needing to do special or complex bbox searches like
> you suggest. 

It doesn't exactly require a stroke of genius to see that potential, 
given that people are already using our internal IDs all over the place 
for lack of something better.

It does, however, require a stroke of genius to find a non-invasive and 
permanent way to solve this problem. Tagging objects with UUIDs is neither.

> It might do so, but it's horribly inefficient as a result of needing
> to do searches across areas, and can't cope with an occupant such as a
> business moving across town

If you investigate the use cases for permantent IDs further, you will 
find that "moving across town" is often a valid reason for actually 
discarding the ID. As in, someone writes a travel guide and wants to 
link to a restaurant ("Chez Fred, an excellent pizza joint in the heart 
of Hamburg with views on the Elbe river traffic..."). Now if "Chez Fred" 
moves across town and is replaced, at the same location, with "Chez 
John", is it useful for the travel guide to still be able to link to 
"Chez Fred"? - Of course, if the travel guide said: "Chez Fred, an 
excellent pizza joint in Hamburg where renowned chef Frederik Ramm 
entertains his guests to Pizza Margherita every Tuesday", then it would 
have made sense to keep the link despite the move (but perhaps not so if 
the owner=... tag had changed...)

For every kind of object and every context in which you link to it, the 
change of some properties might invalidate the link. That's why UUIDs 
are not only clumsy but also not solving the problem.


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