[OSM-talk] Orphaned Relations

[Eugene Alvin Villar]

It's possible that some relations were unintentionally emptied of
their members. In some editors, that would make these relations then
invisible. For some of these relations, someone would have noticed
something missing and then recreated the relation. For others, the
emptying might need to be reverted.

It might help if we can have the bbox's of these relations just before
their members were deleted so that local mappers can determine if the
relations were meant to be deleted or if these relations need to be
reverted.


On Mon, Jul 18, 2011 at 5:55 AM, Sarah Hoffmann <lonvia at denofr.de> wrote:
> Hi,
>
> I recently stumbled upon some empty route relations, so I had a
> closer look at the OSM planet and found that there are about
> 10.000 orphaned relations in the database and the number is growing.
>
> With orphaned I mean relations that have no members and are not
> member of any other relation. Some are completely empty but most
> still have some tags. I have created a list of the relations sorted
> by last editing user here:
>
> http://osm.lonvia.de/stuff/orphans.html
>
> Quite a few of those have been created by some import gone wrong
> but there is also a significant part that are the result of editing
> mistakes. Some relations seem to have been uploaded empty in the
> first place. In some relations, especially multipolygons, the member
> ways were deleted but the relation was left in the DB. And then there
> seem to be some users that think that removing all members from a
> relation is the same as deleting the relation.
>
> According to the created_by tag, this seems to be a problem in
> all major editors:
>
> 4188 JOSM
> 1614 Potlach 1
> 1565 Potlach 2
>  55 Merkaartor
>         2 Mapzen Beta
> 2671 (bots and scripts)
>
> I don't know about forbitting orphaned relations but it would
> certainly be helpful if the editors would show a big red warning
> sign if somebody tries to upload an empty relation.
>
> Question remains what to do with the existing orphaned relations.
> Is there any legimate use for them or would it be save to simply
> delete them all?
>
> Cheers,
>
> Sarah