Hi all, see http://www.mkgmap.org.uk/websvn/revision.php?repname=mkgmap&rev=4072 I am not sure but I think it is a good idea to use 3312 for level 0 for 1'' hgt files now, and 9936 for 3''. As the values are rounded down, 3312 and 3314 will give the same result, as well as 9936 and 9942 My modifications compared to the patch are small, I've introduced constant EXTRA in DEMFile, removed unused import and adapted the unit test. I am not yet convinced that it is needed to round the dem-dist values, but Andrzej is right that this is what Garmin does and therefore it is less likely to cause problems certain devices. Maybe I'll add an option to use the exact value if that means that interpolation can be avoided. I'll also try to find faster code later. Frank is also working on a document regarding the problems adressed in the dem-align patches. Gerd