When i saved the .pdf file using the export icon, the pdf file was perfect. When I saved the file from within the program as png, the result was good as well, although the font size would have to be reduced. I am enclosing circlemesh.m it is very crude.
When I saw that cairo graphics was primarily a 2d system, I thought that might be the issue. Clearly it is not.
the mesh density can be reduced by entering smaller values for nr (radial grid pts) and nt (azimuthal grid pts).
I enclose a copy of the real image I am working on, saved with the export icon. These are the normal modes of an ideal ocean forced by tides.