On Fri, May 2, 2014 at 4:41 PM, John F. Eldredge <john at jfeldredge.com> wrote: > Layer = -1 is not valid data for a waterway that is on the surface, which by definition is layer 0. It is only valid data on an underground waterway. Pfff, Martin, why did you restart this thread ? Water is always below the ground, otherwise it's a flood ;-) Pieren