[OSM-legal-talk] share-alike on generalized data?

[Christoph Hormann]

On Sunday 07 February 2016, Tobias Wendorff wrote:
>
> Just to make it clear:
> Only streets will be derived from OpenStreetMap data, all other data
> are from a proprietary LMA dataset. But the generalization tool
> creates an interaction between both datasets. So the LMA dataset will
> become part of the / a derived database, won't it?

Yes.  Note this works in both ways, if you use OSM street data to modify 
proprietary landuse data this landuse data will be subject to 
share-alike.  Likewise if you use the landuse data to modify the OSM 
street data the modified street data is to be shared.  The latter might 
be permissible by your proprietary license, the former is probably not.

> So actually, I'd need to create a changefile (like OSC) between the
> original proprietary dataset and the derived dataset, which has
> interacted with OpenStreetMap during generalization process. Do I
> only need to release this changefile?

No, whatever you release must be usable by others to reproduce what you 
did, at least as far as data is intermixed.  If you for example also 
have proprietary POIs in your map which are not modified with OSM 
information these do not need to be made available of course.

So if you release a changefile that contains changes to proprietary data 
which itself is not openly available this is useless and irrelevant for 
share-alike.

-- 
Christoph Hormann
http://www.imagico.de/