I'm trying to generate rose plots (circular histograms) using MPL but
have been unable to find a straight forward way to do it. I want to
take the polar_bar.py example and modify it to use the geographic
rather than the mathematical convention for measuring angles, that is
0 is at the top of the plot and increasing clockwise. It seems like
this should be possible using Transformations but I am at a loss for
how to begin. Any hints would be greatly appreciated.