On Friday 15 November 2019, Martin Koppenhoefer wrote: > > > From an engineering perspective the idea that adding OSM data can > > create a derivative database but subtracting OSM data cannot does > > not hold up of course. I can create a polygon data set of the > > Earth surface (a simple rectangle in EPSG:4326) and subtract an OSM > > derived data set of the Earth land masses from that to get a data > > set of the oceans. According to the hypothesis this would not be > > subject to the ODbL. > > You are generalizing in a way that is not suitable.
No, i am not, i am falsifying the hypothesis given by providing an example that contradicts the hypothesis. > [...] IMHO > there isn't OSM data in their dataset. And neither is there is my ocean data set - the OSM data set used only contains land masses, my resulting data set (D2 in Rory's terms) only contains oceans. So no OSM data in it. > The question is not "addition or subtraction", but whether there > is data from OSM in the data. No the question is if when based on the same D1 facebook generates a new D2_a using *changed* OSM data the results are *different*. If that is the case D2/D2_a is a derivative of OSM data. If the question is not "addition or subtraction" consider the following scenario. You create a data set using some AI and big data process of 'potential restaurants' world wide and create a set intersection between those and the restuarants in OSM would the results be a derivative of OSM data? This would only differ from facebooks road data in calculating an intersection rather than a difference as facebook does for the roads. Needless to say i think that if your answer is that this is not an OSM derivative that would be a recipe to de-ODBL-ify any subset of OSM data. -- Christoph Hormann http://www.imagico.de/ _______________________________________________ talk mailing list talk@openstreetmap.org https://lists.openstreetmap.org/listinfo/talk
