[OSM-talk] OSM relation ID property in Wikidata

[Stefan Keller]

Hi,

You wrote:
> - it's roughly in that bounding box (e.g. the city or a given part of

A soon as you use the word "roughly" - the id approach is doomed to fail.
According to OO and database technology an id is a well-defined
surrogate with a well-defined data type.

Yours, Stefan


2013/5/7 Peter Wendorff <wendorff at uni-paderborn.de>:
> 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
>