[OSM-legal-talk] Extent of share alike?

Frederik Ramm frederik at remote.org
Mon Nov 2 11:27:39 GMT 2009


Hallo,

Matt Amos wrote:
>> However, my question is, how far does the share alike
>> section of the Creative Commons licence go. I want to share the map data
>> with OSM but not the other sections of the work.
> 
> this lack of clarity is one of the problems with the CC BY-SA license.
> the short answer is: i'm not sure. the longer answer is: the image you
> render to the screen must be CC BY-SA licensed,

... not so fast! We generally say that:

* if you produce an image that contains OSM and other data, then deliver 
this image to the client computer, then the whole image is CC-BY-SA.

but

* if you produce two different images, one with OSM and one with other 
data, and the two are overlaid on the client computer (by software 
acting on behalf of the user), then your second image can be licensed 
whatever you want. Only if the user (who is considered to have created a 
derived product by asking software running on his computer to take two 
images and merge them) then further publishes the image - which you may 
or may not allow as the image contains your data! - would the image have 
to be made CC-BY-SA.

Otherwise it would not be possible to e.g. overlay OSM data and CGIAR 
"noncommercial use only" hill shading in an OpenLayers application.

Bye
Frederik




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