[OSM-legal-talk] What licences (other than ODbL) are compatible with OSM after 1st April

[mayeul.kauffmann at free.fr]

Hello,
Short version:
I think data licensed under CC-BY-SA 3.0 cannot be put under ODbL without written authorisation by the copyright owner. Can you confirm this?


Long version:
I'm currently discussing with the copyright owner of a large database. They are a non profit organisation and want to release their data under a permissive licence to help integrate it in OSM or other projects. I suggested them to use ODbL but they would prefer CC-BY-SA 3.0, saying that it is compatible with ODbL as the following human-readable version of the license mentions "similar" licences:
http://creativecommons.org/licenses/by-sa/3.0/

IMHO they are mistaken: I believe data licensed under CC-BY-SA 3.0 cannot be put under ODbL without written authorisation by the copyright owner. Can you confirm this?

I would suggest them to release either under ODbL or under both  ODbL and  CC-BY-SA 3.0 (I think they have ruled out more permissive licences like CC-BY, CC0 or public domain).

What do you think?
Thanks,
Mayeul