[Osmf-talk] my views on the ODbL

Frederik Ramm frederik at remote.org
Sat Dec 5 13:32:28 UTC 2009


80n wrote:
> Both sets of data will be available.  There will probably be two files:  
> odbl-planet.osm and ccbysa-planet.osm each containing different data.
> You may be able to technically combine the two databases to create a 
> single map, but I don't think you would be able to publish it as the two 
> licenses are incompatible.  I think the most you can expect is that the 
> two maps could be viewed as separate layers.
> Can anyone with a deeper understanding of the new license comment on 
> what would happen if you mixed the two datasets? 

My reading is that it would be perfectly legal to load the ccbysa-planet 
and the odbl-planet both into separate tables on our tile server and 
then configure Mapnik rendering in a way that creates tiles from them. 
These tiles would then have to by CC-BY-SA licensed.

I see this as a technical challenge more than a legal one. What we would 
really need for this is not a ccbysa-planet but a 
ccbysa-not-relicensed-planet, i.e. a file that contains all data that 
has not been relicensed. This could then be mixed (in a "collective 
rather than derivative database" situation) with ODbL data.

Of course there will me myriad technical problems like what happens if 
you have a relation parts of which are in one file and parts in another. 
In order not to trigger ODbL on the CC-BY-SA content you must refrain 
from mixing data into a derivative database, it may only be mixed into 
non-database products...

If the OSMF members agree to proceed with the license change, then it 
would make sense to start thinking about these issues, e.g. whether we 
want to include non-relicensed data in our tiles and how we are going to 
do that.

If we do that, then this may lead to some minor forking of the project. 
Not something terribly bad but technically complex. Imagine there's a 
whole village somewhere remote, the data for which has not been 
relicensed. The village appears on the map through some "we also use old 
data for rendering" magic. A road in that village is renamed, and I read 
about this in the paper. I cannot copy the whole village, or even just 
that one road, over to the current ODbL dataset because that would be a 
CC-BY-SA violation. If there was some chance to point my JOSM to the old 
dataset and make the change, even if that change is then CC-BY-SA, I 
would probably do that. I could imagine that we'd be seeing something 
like this - people not forking in order to set up a competing project, 
but people operating forked infrastructure in order to allow the interim 
maintenance of non-relicensed data, until such time it has been resurveyed.

The only way to avoid this would probably be orchestrating a massive 
rejection drive against non-relicensed data, including deliberately 
leaving out the data from our map tiles as if it didn't exist. That 
would force people to resurvey missing data more quickly rather than 
having the old stuff stick around, but it could also alienate some.


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