On Saturday 18 May 2013, Yohan Boniface wrote: > On 05/18/2013 03:55 PM, malenki wrote: > > Dave F. wrote: > >> IMO Source should be on the object, not on the changeset. > > > > +1 (except if there is one changeset for one object (; ) > > This is not my opinion. Let's take a simple example: a school. > > [...]
The problem is currently neither changeset nor object tags are really a good solution for true metadata (that is information characterizing the data and not the real world object). Changeset tags have mainly two problems: - they always apply to the whole changeset so everything you map together needs to have the same metadata. This might seem to be a problem primarily for imports but it can also be troublesome in manual mapping - imagine mapping something based on satellite images and you need to use different images for various parts due to clouds or even the common case of supplementing survey data with Bing images. - many large objects are included in a lot of changesets without actually being substantially modified (like moving a single node in a 500 node way etc.) This means finding the actual changeset a certain geometry originates from to get the metadata information is not so easy. The solution in my opinion would be to have separate metadata tags which are reset everytime a substantial change is made to the data they refer to unless the user explicitly sets them (either individually or for the whole changeset). Geometry metadata tags for example would be reset if: - in case of a node the node is moved - in case of a way more than X percent of the nodes are changed (X being something like 30) - in case of a multipolygon more than X percent of the ways are added/removed or substantially modified This would not be fool proof of course (small changes could accumulate to a substantial change without being noticed). Greetings, -- Christoph Hormann http://www.imagico.de/ _______________________________________________ talk mailing list [email protected] http://lists.openstreetmap.org/listinfo/talk
