[OSM-talk] Import guidelines proposal update

[Paul Norman]

> From: Lester Caine [mailto:lester at lsces.co.uk]
> Subject: Re: [OSM-talk] Import guidelines proposal update
> 
> who last edited an object! ). Where the import HAS nice unique object
> identifiers things are a lot easier, but raw vector data like the French
> import, and I think the Spanish data you are talking about CAN still be
> 'diffed' against earlier imports, and result in perhaps new data that
> can simply be imported, or perhaps an overlay that identifies conflicts
> that need a human eye. Isn't it better to spend time working out a GOOD
> way of using the data going forward rather than having to manually merge
> the whole lot again in a couple of years time ... and every couple of
> years.

My thoughts on how to handle this for data with persistent unique
identifiers without adding those as tags is to

a. Record the correspondence between source ID and temporary pre-upload
negative OSM ID

b. Record the correspondence between pre-upload negative OSM ID and OSM ID

c. Combine for a correspondence between source ID and OSM ID, and save this

d. When updating, identify objects that have changed or been added to the
source

e. For changed or deleted objects if the OSM object was last edited by the
importer's import account, upload a new version reflecting the changes.
Objects that have been edited by a person will require manual intervention,
like now

f. Handle new objects like before
	
g. Identify objects deleted in OSM and check these, then submit corrections
to the source.

The one case this doesn't handle very well is POIs that have been changed
from a node into a way.

I'm going to be working on implementing this in a limited way for updating
addresses locally. Addresses are different because the address should be
unique in the city.