Hi, i have find with a lot of "trial and error" a algorithm to create DEM-Files for a Height-Profil. You can find the description (in german) at https://github.com/FSofTlpz/Garmin-DEM-Build/blob/master/DEM-Daten.pdf With this data we can for example draw a track in mapsource or basemap and we at once the Height-Profil of our track. At second, the map looks like better. I have create a experimental program called BuildDEMFile :) to build this files. Experimental means, the encoder is for exploring the algorithm but not for speed. You can find the programit at https://github.com/FSofTlpz/Garmin-DEM-Build. It is possible, that there minor bugs, but i have it successfull testet for 2 different germany-maps. I have a wish: Can you in mkgmap insert a new option, for example --dem with path to DEM-files, and include these files in the join-process for the IMG-files? So far only joined the LBL-, NET-, NOD-, RGN- and TRE-File. Also should be set the dem-flag in TDB-File. If so, i can build the DEM-Files with area-size from the splitter-file areas.list. I hope thats the same like in the TRE-Files? That would be a little bit easier then my fiddly way: split the ready IMG-files, build the DEM-files and then join the files to new IMG-files. And at last i must change the dem-flag in the TDB-File. with best regards Frank --- Diese E-Mail wurde von Avast Antivirus-Software auf Viren geprüft. https://www.avast.com/antivirus