Am 07.05.2013 09:43, schrieb Stefan Keller: > Hi, > > All use cases you describe are valid. It's up to the users of OSM > permanent id to keep track of changing OSM ids - it's an offer of OSM. > The only constraint I would propose is to avoid to delete and recreate > a new id only because of a tool (like an editor) likes to do it like > this. > > The concept of permanent, unique and never-reused object ids is a > well-known property in the Object-Oriented and Linked Data technology. > > As I said: The killer criteria not to use overpass-approach is that > there exist many OSM objects which have too few or no tags at all. And > using coordinates as identifiers is no solution neither because it's a > float number with different precision and implementation dependent. OO > overcame exactly this restriction of the relational paradigm (which > identified a tupel by the set of it's values).
But even then overpass is slightly better: Let's say I only know I want to link a given supermarket. Let's say that supermarket is not tagged in more detail then shop=supermarket. Linking to node 123 would break soon when that get's a polygon (not to mention mappers who don't know or care about theory of data management and reuse that node directly to map a waste_basket instead of creating a new object). Best case here would be a mapper that includes that node as one of the nodes building the polygon - but who knows? Overpass in contrast could add information about: - we want to link a supermarket - it's roughly in that bounding box (e.g. the city or a given part of the city) Of course this can break, too - but it's more stable than the ID alone, even without any tag at all. regards Peter _______________________________________________ talk mailing list [email protected] http://lists.openstreetmap.org/listinfo/talk
