Hi Therion people, I've just noticed that flipping an extended elevation scrap using “-flip horizontal” it changes the numbering of the lines points on the th2 file when the file is processed by the config file. I was trying to line join the top line of one elevation survey with the top line of another survey using "join linetop@normal:end linetop@flipped:0" as the “normal:end” line was accidentally drawn clockwise and “flipped:0” was drawn anti-clockwise it makes sense that end and zero were the join points However when the file was run it was necessary to change it to be "join linetop@normal:end linetop@flipped:end" to get the two lines to join, it's not a problem, just something I wasn't aware of. Regards, Alastair. Sent from Outlook for iOS<https://aka.ms/o0ukef>