[Imports] Blog post about imports

[Dan S]

2014-03-13 20:54 GMT+00:00 Ilpo Järvinen <ilpo.jarvinen at helsinki.fi>:
> On Thu, 13 Mar 2014, Christian Quest wrote:
>
>> Regarding import related tags, some are really useless, some like unique IDs
>> have not been sucessfully used in many cases up to now, but this doesn't
>> mean we will never be able to take advantage of them.
>
> I've never really understood why one would _ever_ want to have the foreign
> IDs, unique or not, for things that should remain spatially stable
> (roads, buildings, etc.) because the foreign dataset should be rather
> trivially diffable against older version of itself. That way, the IDs of
> the foreign data are pretty useless to begin with because the diffing
> produces the very cases that would need to be checked regardless of IDs.
> Obviously the previous version(s) need to be preserved though for the
> diffing to be possible.
>
> Besides, the foreign unique IDs usually don't have well defined rules
> anyway, so in case they redo something there would be rather little
> guarantees on how the foreign IDs will be in the end. Which is pretty
> similar results as what we get ourselves with OSM ids when we edit
> by splitting and joining.
>
> For POI type data where re-location is much more realistic compared with
> rather fixed features such as roads and buildings, I can somewhat
> understand that there might be some use for the foreign IDs but even there
> the update process would probably get most out of the foreign data by
> diffing foreign dataset against itself first.

I'd just like to point out that there exists a world of data outside
OSM, and foreign IDs are very useful in combining OSM data with other
datasets to derive new insights, new services, etc.

http://linkeddata.org/

Dan