we use Therion to make an intermediate map and then we finish it on illustrator.
To make the wall buffer for the wall we need the wall to be one line.
In order to do that we must use "continue" option when we draw in Topodroid (which is not always the most convenient one), or after we finish the sketch we need to go over it and use "attach to line" option in Topodroid to make it a single line.
The "attach to line" option is still in tester mode and it is not fully reliable (sometimes it delete the line).
if there was an option to do it in Therion it would make things much easier.
Omri