[OSM-legal-talk] The edges of share-alike on data Re: Attribution

[Jean-Marc Liotier]

On 05/05/2014 17:26, Martin Koppenhoefer wrote:
> no, this was not about overlaying 2 graphical layers but about joining 
> the data into one layer (necessary I guess, in order to perform 
> routing). [..]

Usage may be different, but the data is the same: ways with an 
hypothetical 'speed' attribute added to them in the persistent database 
of your choice. Whether you use that joined data to perform Dijkstra 
stunts or just render it graphically does not change its nature. In 
either case, no Openstreetmap data is altered in any way - only extended 
thus meeting the definition of a Collective Database.

To give a counter-example, if the speed data was used to guess 
maxspeed=* or change some of the highway=* classification according to 
detected speeds, then Openstreetmap data would be altered and there 
would be a Derivative Database.