0> In article <68B4C1B8-4426-4453-8B09-00B90F870F01@gmx.de>, 0> Thilo Hannemann <URL:mailto:thannema@gmx.de> ("Thilo") wrote: Thilo> So especially with your solution to integrate the contour lines Thilo> into the map this is IMHO a derivative work, so that all components Thilo> of it must be subject to the OSM license. Agreed. I believe (but I'm not any kind of lawyer!). I'd say that separate invocations of mkgmap (one with OSM data and one with contour data) would be fine - it's perfectly possible for a user to then combine them into a single gmapsupp for their device. In fact, separate maps is probably also the best plan for those of us generating maps for our own use (and not distributing them), as the contour maps should be a one-shot task. Things would get complicated if the contour generation algorithm uses water body data to discover flat regions, though. P.S. it would be interesting to see contour regions (as opposed to lines) suitable for elevation shading layers; another idea is to compute slope aspect for a hill shading layer - maybe I'll look into that when I get time...