Jeff, > Eric: Thanks - contour indeed now seems to work perfectly with masked > arrays, but I still have problems with contourf (see attached > ortho_test.png). Unfortunately, neither of your suggested workarounds > help, the first makes no difference and the second makes it much worse. > -Jeff It is not working in your basemap/examples/contour_demo.py, either, so this does not seem to be exclusively a masked array support problem. I hope I can figure it out. Eric