[OSM-legal-talk] The Copyright of Split Ways

andrzej zaborowski balrogg at gmail.com
Mon Jan 30 11:36:28 GMT 2012


On 30 January 2012 12:13, Richard Fairhurst <richard at systemed.net> wrote:
> Frederik Ramm wrote:
>> There's no reason for such vodoo logic. A way split or merge can
>> be determined from looking at a changeset. A changeset in which
>> a chain of nodes is removed from one way and added to another,
>> new way denotes a split.
>
> I don't think that's necessarily true.
>
> If we have:
>
> (state before changeset)
>    way i=[ABCDEFGHIJK], { highway=unclassified; name=Frog Street }
> (state after changeset)
>    way j=[ABCDEF], { highway=unclassified; name=Frog Street }
>    way k=[FGHIJK], { highway=unclassified; name=Mog Walk }
>
> we cannot say with certainty that there is a split. All we know are that two
> new ways have been created using the nodes that were in a previous, now
> deleted way. The name "Frog Street" might be carried over from way i, but
> then again it might have been entered afresh by the changeset creator.
> There's no way to tell.
>
> _If_ it was i->i+j, rather than i->j+k, then that tilts the balance in
> favour of a split. But even then it's not certain. In the absence of editor
> and API support, there's no way to tell for sure.

(I thought it is i->i+j, at least in JOSM it was up to some point)

In any case if a way is an arrangement of node references + some tags,
then if inside some changeset an arrangement of nodes and/or tags is
reused, as in your example, then, even if the editor's "split"
operation wasn't used to arrive at it, for practical purposes the
effects is the same.  In practice the operation was a split, wasn't
it?  (A changeset browser that could recognise that would be a really
useful service, I think someone was even working on one)

Cheers



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