In reply to Beaker:
> OS doesn't make a claim to the copyright of location names, the shape of the landscape or the altitude of a specific location - just like Rockfax, "it is just [the] presentation of this information that you pay for" when you buy an OS map...
My understanding of the situation is that you are not correct in this statement and they actually do claim more than the 'presentation'.
Here is an illustration of the problem I faced. I had a licence from one map company to use their maps as reference works for our maps. Occasionally these weren't detailed enough to cover the maps we wanted so I would use the licensed map to create an accurate relative view of the area covered - contours, roads, streams, etc. - and then make a much bigger version. On this I could then add extra observed detail. This is a perfectly legit way to create a map, in fact it is often essential since no map from anyone contains all the info you need on a crag approach map to many crags. The irony of this was that the more accurate I got this detail, the more likely I was to get the OS tapping on my shoulder. That was my complaint with the 'derived data' restriction, it seemed to be upside down logic.
I realise that this is a complex issue, as several people have pointed out on this thread and by email, and that the article probably doesn't do justice to this complexity, however I do feel that this thread is developing into a good discussion with some knowledgeable individuals putting forward good points.
Alan