With some detours, I finally got the elevation profile working in my mapset ;-) I dont know if it now worked because I also installed Garmin Basecamp. First, I had all map tiles and contour img's in one mapset. They are still there, but now I created another tdb index file with mkgmap on all contour img's from the same mapset, with the options: --overview-mapname: contours_nl --show-profiles=1 --tdbfile I stored the contours_nl.tdb file and contours_nl.img overview map in the same directory, and installed it in Mapsource. The result is that I see the contours on top of the map (with routing), and I can choose to switch to the bare contour mapset without all osm data. In this mapset I can see now the elevation profile :-) On the GPS (tested a Etrex and Dakota) I can now switch the contours on and off, but routing doesn't show the elevation profile. You can download and view some images of my custom maps on my website: http://sites.google.com/site/openfietsmap