[Matplotlib-users] Alpha keyword not working with contourf

[Alexa V. <ale...@gm...>]

Hi All,

I'm just getting started with matplotlib. I'm trying to make a contour plot
using contourf and have the different paths colored and semi transparent
but the alpha keyword doesn't seem to do anything. I googled around and
found that other people have had this same problem but I didn't find a
solution. Here's what I'm doing -

contourf(metals, U, o3, levels=[o3col-nsig*o3sig, o3col+nsig*o3sig], alpha=
0.20, colors='magenta')

contourf(metals, U, o2, levels=[o2col-nsig*o2sig, o2col+nsig*o2sig], alpha=
0.20, colors='blue')

contourf(metals, U, c3, levels=[c3col-nsig*c3sig, c3col+nsig*c3sig], alpha=
0.20, colors='green')


To plot them all together.
For reference my machine is running Mac OS X 10.6.8 and my version of
matplotlib is 1.2.x

Thanks!