Hi, On 12/11/2012 01:04 AM, Paul Norman wrote:
Lots of people include IDs because they think they might be useful but very seldom are they actually used.
I can second that. I have witnessed many imports painstakingly preserving the ID (because, after all, most of us are IT people and our brains are hard-wired to think that ID numbers *must* be useful - you know, you can cross reference things and stuff with IDs!) but I've yet to see anyone doing something useful with them.
I have never seen anyone who actually imported IDs and had a plan when asked - inevitably, the answer was "it might be useful someday, I don't know".
Now one of the things we say we want to do is offer data for "unexpected uses" so it may sound short-sighted to throw out an ID just because you cannot envisage a good use for it at this point in time.
On the other hand, preserving an ID in the database might send the wrong signal to mappers. Are they "allowed" to change something that has an official GIS ID? What if they split or merge objects that carry such an ID? Will their changes be overwritten later if they don't remove the ID? Etc.
My suggestion would be to not import the ID, but create a correspondence table during import ("imported object with ID #1234 as way #2345"). Since any import has to be properly documented anyway, the list can be stored with the other logs/documentation. If one should really want to follow up on this later, one can check if the objects still exist and haven't been modified, and then update/amend them or do whatever other useful thing the ID enables one to do, without polluting the database or puzzling mappers.
Bye Frederik -- Frederik Ramm ## eMail frede...@remote.org ## N49°00'09" E008°23'33" _______________________________________________ Talk-us mailing list Talk-us@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk-us
