"A consequence of that would be that it is not infringing copyright to make a copy of a map, provided you only copy the factual data and not any of the creative part."
This is correct. "The protection that each map receives extends only to its original expression, and neither the facts nor the idea embodied in the maps is protected." (Mason v. Montgomery Data, Inc., http://www.coolcopyright.com/cases/fulltext/masonmontgome...)