2009/12/6 80n <80n...@gmail.com>: > On Sun, Dec 6, 2009 at 5:47 PM, Tobias Knerr <o...@tobias-knerr.de> wrote: >> >> Pieren wrote: >> > Could someone deliver a script that could make this automatically for >> > me :"take all elements where I am the last contributor but not the >> > only one then delete and recreate them identically under my user >> > account then all my efforts are saved at the licence transition" ? >> >> In my opinion, whether your data is derived from other data isn't >> determined by having the same object ID. If I completely remove all tags >> from a node, move it somewhere else and add new tags, then it's most >> likely not derived from the previous work. If I add a tag to a road, >> then it is derived from previous work, and this doesn't change at all if >> I choose to copy the road and delete the original. >> >> Using the object history is just an approximation based on the >> assumption that mappers will usually keep an object if they are >> improving existing data, and create new objects if they add completely >> new information. It's not really possible for an automated process to do >> anything else. >> > Actually even this doesn't work. If a way is split into two (using JOSM) > then the database does not record any information about the split and the > history is kept with only one of the ways. > > This means that the history and original attribution for half of all the > split ways is just not there. I don't think there's going to be a way of > deleting all the data for those people who don't accept the new license.
One way of preserving the actual "logical" history of elements through the edits that works more often than looking at the id, but not in 100% cases either, is by looking at the tags, such as source= (if present). That's why I advocate linking to other databases by including those database's key in a tag (such as wikipedia= ). In this case if a changeset creates an element with source= or source:ref= value identical to some other element in the same changeset, it probably shares the IP ownership with those other elements. In practice I think it's going to be easier because most edits on ways / relations only bump up the version on the way / relation object and you rarely touch the nodes, which actually hold the geo reference value. If you create a way using the nodes a different way was using till that point, it's probably a piece of the same way. If a way/relation needs to be deleted because its long history includes a mapper who opted out, it can be easily recreated if you have the nodes. Cheers _______________________________________________ talk mailing list talk@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk
