I am curious to see what you find does the trick. As for my coastline problem, the good news is that I can now import the geometry. The bad news is that when I solve the weak for of the PDE it does not impose the Dirichlet BCs. At the moment I am trying bc = DirichletBC(z.sub(0), 0.0, "on_boundary") I remember having a similar problem a while back and I needed to specify the name of the boundary and use that to impose the condition. What is the current practice for meshes that we import? Cheers, Francis ------------------ Francis Poulin Associate Dean, Undergraduate Studies Associate Professor Department of Applied Mathematics University of Waterloo email: fpoulin@uwaterloo.ca Web: https://uwaterloo.ca/poulin-research-group/ Telephone: +1 519 888 4567 x32637 ________________________________ From: G. D. McBain <gdmcbain@protonmail.com> Sent: Thursday, November 2, 2017 8:53:47 PM To: Francis Poulin Cc: firedrake@imperial.ac.uk Subject: Re: [firedrake] problems with importing a mesh Yes, that did the trick. I used your idea in many different tests that I have done and basically added the second of the following two lines and that seemed to do the trick. Thank you! ... Plane Surface(1) = {1}; Physical Surface(2) = {1}; Great! You're welcome. So you didn't need the Physical Line… I wonder if my warning about those being required all round were wrong or outdated… Let me check.