Frederik Ramm wrote: > Will the planet dump and/or diffs be extended so that they contain all > changesets too, or what should be the preferred mode of operation for a > third-party application that wants to track changesets? The only way I > can currently think of would be looking at diffs to find out which > changeset IDs were active and then download them individually. Have I > overlooked something? > Replication of changesets is on my undocumented long term TODO list for osmosis (I should add it to trac) but I don't know when I'll be able to do it. I had some discussions with Shaun and Matt a while back on how this might be done efficiently. Identifying changesets for replication is a bit tricky and would probably involve two passes, first pass would identify all changesets created in a time interval, and the second pass would identify all changesets modified (ie. have entities referring to them) in a time interval. Once identified they could be read and included in a changeset file just like any other entity.
The reason they're more difficult than other entities is twofold. 1. They don't have a history table so modifications are much harder to detect. 2. The bounding box information attached to each cannot be computed by osmosis in a "streamy" fashion which means they have to be re-replicated if they change. The two stages of changeset identification cause other problems such as being able to retrieve changesets after identification in an efficient manner (ie. not one by one), and potentially having to store identifiers in memory which is problematic at least theoretically if long interval changesets are being extracted (not likely to be an issue for the current daily changesets). Bit of a brain dump there but they're some of the reasons I'm holding off until I have a decent amount of time to invest in it. However, if replicating into a database osmosis will "invent" changesets. It will create one changeset per user per changeset interval which will approximate the real thing. It won't help if you need the real changeset id though. Brett _______________________________________________ dev mailing list [email protected] http://lists.openstreetmap.org/listinfo/dev
