How is mkgmap expected to behave when input files grow in size? Is a linear inrease in calculation time - i.e. O(n) - expected, or an increase beyond linearity? E.g. when I create a map with routable lines for bicycle, mkgmap takes some 30 minutes for Germany alone (3 GB pbf file resulting in 850 MB img file), but more than 2 hours for Germany and some neighboring countries (7 GB o5m file, resulting 1.4 GB img). Are there many calculations at O(n^2) or beyond in mkgmap, or is this due to other factors, e.g. memory limitation? Notes: mkgmap is called by %JAVA% -Xmx6800M -ea -jar %MKGMAP% .... on 64bit Win 7; swapping to disc does not occur. But I am more interested in a general rule than in some hints for improving the performance in this concrete case. E.g. how I could estimate the duration if I add some further countries... Thanks for your hints.