[Osmf-talk] CC BY SA 2.0 and backup plan

[Matt Amos]

80n wrote:
> On Sat, Dec 5, 2009 at 6:15 PM, Matt Amos <matt at asklater.com 
> <mailto:matt at asklater.com>> wrote:
>     you probably *can* publish a map based on a collective database of
>     CC BY-SA data and ODbL data, and the produced work will be CC BY-SA
>     licensed.
> 
>     i think you *can* publish a map based on a collective database of CC
>     BY-SA data and a derivative of ODbL data, and the produced work will
>     be CC BY-SA licensed and the whole dump, or diff, of the derivative
>     ODbL data must be available.
> 
>     i think you *can* publish a map based on a collective database of CC
>     BY-SA derivative data and a derivative of ODbL data as long as the
>     derivative doesn't "represent, in terms of obtaining, verification
>     or presentation, significant investment", and the produced work is
>     CC BY-SA, and the diff/dump of the ODbL data is made available.
> 
> I'm still thinking this through but how would you create the ODbL 
> derivative database?  You'd have to do it without any recourse to the CC 
> BY-SA data and I don't see how that would be possible.

the clearest example is if you create it with no recourse to the CC 
BY-SA data. for example, if you run osm2pgsql to create the two 
independent databases, you can generate (CC BY-SA) tiles from mapnik and 
distribute them. i don't see any license conflict here.

a less clear example is if the modification doesn't "represent, in terms 
of obtaining, verification or presentation, significant investment". for 
example, if i have two apidb format databases and take the list of 
elements in the ODbL database and delete them from the CC BY-SA database 
then (it's my understanding that) i can still render CC BY-SA tiles from 
the resulting collective database. and, since CC BY-SA doesn't require 
that i release the database, i don't have anything else to release.

it gets even murkier if i do it the other way around, but if the list of 
elements in the CC BY-SA database doesn't "represent ... significant 
investment" then i think it's likely i can delete them from the ODbL 
database and only release that list. again, the tiles produced from the 
resulting collective database would be CC BY-SA.

cheers,

matt