On 15 November 2012 05:44, Paul Norman <[email protected]> wrote: > The > additional attribute prevents the files from working in JOSM
Oh, really? That sucks. I went for the additional attribute because I expect XML parsers to ignore it if they didn't understand it. > but the bigger > issue is the use of positive IDs. When an object is merged in JOSM it > carries over its ID if it's a positive ID. This would lead to conflicts with > existing data in the API. Even if JOSM were patched to allow it to work with > these files and special-case their positive IDs, using positive IDs seems > like a recipe for disaster, particularly when a standardized format exists. Well, I wouldn't say that negative ids are standardized, just that p2 and JOSM use the same convention. I believe Merkaartor uses guids as placeholder ids, in contrast. Additionally, negative ids for background layers don't seem like the right solution to me, because that still gives a shared id space. What happens if you have three background layers, each with a node id="-1"? Or you create a new way in the main layer, and then pull through a way with a matching negative id? Potlatch approaches this in a "more correct" fashion. Each vector layer has its own id space. When objects are copied to the main layer their ids aren't carried over - the main "osm" layer creates corresponding new entities, copies attributes, and takes care of the placeholder id assignment. I suspect JOSM will need to handle things in a similar manner. The "recipe for disaster" of using positive ids in vector layers is, as I see it, due to JOSM assuming that all the different layers are in the same id space. So does snapshot-server serving negative ids actually solve the problem, or will it still lead to id space conflicts? Cheers, Andy P.S. I don't think there's actually any osm_id handling code in snapshot-server anyway, it just uses the same ids as are in the .osm file in the first place. _______________________________________________ Potlatch-dev mailing list [email protected] http://lists.openstreetmap.org/listinfo/potlatch-dev
