I tried to use contourf to plot an array in which the land values have been masked. However, I found that contourf did not deal with the masking properly. I would expect the masked region to be bounded by the separation line of land and sea, but it actually exceeds that line. I also tried with pcolor and this time the masking is handled correctly. Could anybody tell me what is the right way to use contourf for plotting masked arrays? Thanks!