[Imports] [OpenSeaMap-develop] Fwd: NOAA Imports

[Jaak Laineste]

On 16.01.2013, at 20:43, Malcolm Herring wrote:

> On 16/01/2013 18:32, Jaak Laineste wrote:
>> OSM IDs are more or less persistent AFAIK.
> 
> Even this cannot be guaranteed. Mappers who merge two nodes destroy one of the ID's. This then breaks any external DB linkage that relies on the deleted ID as a cross-reference.

 At least my quick test result is that the ID remains there, it is marked with ver=2 and deleted. Even if it would be are lost, then update script could mark it as "edited in OSM" and do conflict resolution (skip updates, forces manual review or smth). Problem would be when essentially same node ID is changed without marking history, or when deleted node ID is reused. Could this happen really? Is there deleted node cleanup process in API database?

 As far as I know OSM ID is officially not guaranteed to last forever and stay the same, but my impression is that in practise it works this way quite well.

Jaak