[Rebuild] Switching a tile server over to clean data

[Frederik Ramm]

Hi,

On 04/17/12 10:46, Paul Norman wrote:
>> Yes although I could see some leniency in the period immediately after
>> the changeover, i.e. I think OSMF should say "for a few months after the
>> changeover, even if it is technically an attribution requirement
>> violation if you just leave the old "Tiles CC-By-SA Data(c) OSM" in
>> place, we'll not prosecute you for that".
>
> That would be good. I'm not sure that OSMF can make it binding on
> contributors but I doubt anyone would seriously want to sue or send takedown
> notices over that.

I think that only OSMF owns the database right (or is the other side of 
the contract if you view OdBL as a contract) so no individual mapper can 
sue an OSM user over misattributing data, and neither can they sue OSMF 
for not sending takedown notices. (OSMF has promised to the mapper that 
they will only distribute the data under ODbL or CC-BY-SA; they have not 
said anything about how far they intend to go in enforcing it.)

>> No, that is not correct. Since the two databases (shapefile with CC-BY-
>> SA coastline, postgresql database with ODbL content) are at no point
>> mixed into a common derived database, you can make produced works and
>> distribute them.
>
> I see a tile image falling under a derivative work, not a collective work,
> as defined in CC BY-SA 2.0. Unlike a periodical issue or anthology it is not
> possible to distinguish the different sources. CC BY-SA 3.0 is clearer on
> this.

Yes. The tile image is a derived work in the sense of CC-BY-SA 2.0. This 
means that the tile image must be licensed under CC-BY-SA 2.0, which it 
is. The fact that the image contains extra info from another, 
non-CC-BY-SA source does not pose a problem for CC-BY-SA. At the same 
time the image is a produced work from an ODbL data source. The only 
requirement that ODbL has for produced works is attribution. Attribution 
is guaranteed by CC-BY-SA so ODbL is satisfied as well. Now *even if* 
one wanted to enforce that ODbL requires different attribution ("made 
from ODbL OSM data which is available here") than CC-BY-SA ("made from 
CC-BY-SA OSM data"), then it would *still* be legally possible to make 
this derived/produced work as CC-BY-SA does not preclude additional 
attribution from being added (it precludes additional conditions being 
added but not additional attribution).

So, to be super correct, the interim tiles would have to be CC-BY-SA and 
carry an attribution of "made partly of OSM ODbL data which is available 
here, and partly of OSM CC-BY-SA data".

> Also - I'm not sure why it matters if it's a database where they're mixed or
> an image where they're mixed - they're both works protected by copyright.
> 3.0 is clearer on this point

It matters for ODbL because if the "thing" you were distributing was a 
database then ODbL would mandate that it be ODbL licensed, and both 
licenses' viral rules would indeed clash. But if the "thing" is a 
non-database then ODbL does not require anything more than attribution.

> You could mix ODbL and non-open data sources in a derivative work, but not
> CC BY-SA and non-open sources.

Yes.

> In any cases, the coastline is not looking like a major issue, we're down to
> 50 breakage points. I don't really want to get into a lengthy discussion on
> this point since it doesn't impact the possible solutions for the caching
> issue.

Agreed, but especially since the ODbL is new, I think it is very 
important that we all have the same understanding. It would not be 
helpful for OSM if some experienced OSMers claim that you cannot do X 
whereas others say you can. Your coastline example above would in the 
future apply just the same to any other mixing of CC-BY-SA data and OSM 
data (e.g. tiles from OSM with some points from Wikipedia plotted onto 
them).

> The more I think about it, the more I like offering the first planet also as
> cc by-sa. If OSMF doesn't do this, I may dump my pgsnapshot database to do
> the equivalent.

That would not help the legally paranoid. Your pgsnapshot dump would not 
be dual-licensed; it would be CC-BY-SA-only licensed. Making tiles from 
that doesn't flush your cache, it just adds more CC-BY-SA-only tiles 
that you cannot suddenly declare to be ODbL produced works! Of course, 
nobody would be able to spot the difference because there is no 
difference in the data.

Bye
Frederik

-- 
Frederik Ramm  ##  eMail frederik at remote.org  ##  N49°00'09" E008°23'33"