Problem with contourf plotting

I seem to have a problem with the contourf function. The data I am plotting (see attached) seems to plot fine with the 'surf' command and 'contour' as well, but the plot changes when I use contourf. I am using the following command for plot the data:

contourf(p_R,Q_R,pow_R);

I have included examples of each of the plots to show the difference between contourf, surf, and contour. I have reproduced this issue on another computer. Does anyone know if there is some bug in contourf that would cause this issue?

I found a work around by using 'flipud' on each of the matricies, but I don't know why this works.

contourf(flipud(p_R),flipud(Q_R),flipud(pow_R));

I have included a plot of this result as well.

Any ideas on what the problem is? (I am running 2013b)

Thanks, -Michael

Answer 1

[Mike Garrity]

I think I've seen that one before and that it's fixed in R2014b.

If I remember correctly, it had something to do with the way the grid doubled over on itself as you can see along the right side of your example if you zoom in. Even in the best case that sort of doubling over causes some strange effects with contours. It's not really clear to me exactly what's "correct" in this situation, but clearly what 13b is doing is not correct! Here's what I get with 14b.

Any chance you could give it a try with the new release and see what you think?

[Michael]

Awesome. Thanks. Looks like it is time to upgrade.