Hi Programmers, first see http://www.mkgmap.org.uk/pipermail/mkgmap-dev/2012q1/014145.html I see two different interpretations: 1) mkgmap encodes the initial heading (A-B) and the final heading (C-D), always using one byte "curve data " for the final heading. 2) display tool displays the initial heading as "direction", and one or two bytes curve data My theory is that the two byte curve data is used when we have a road where initial heading AND final heading are (very) different from the direction (A-D). Question is: what value is stored in the different fields? Does anybody already know more details? If not, what is the best way to find out? I could either try to write a program that displays the data in real maps, or I could simply use try and error in the mkgmap write routine to find out how MapSource reacts one different codings. I played a little bit with the latter and I see differences in the calculated times. Gerd