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. _______________________________________________ Imports mailing list [email protected] https://lists.openstreetmap.org/listinfo/imports
