If you want to have a legend for PolyCollection, you may use a proxy artist.
http://matplotlib.sourceforge.net/users/legend_guide.html#using-proxy-artist
Thanks for the link! Although, it seems that legend does not support PolyCollection at all:
"Remember that some pyplot commands return artist not supported by legend, e.g., fill_between() returns PolyCollection that is not supported."
so that even trying to use a proxy artist results in an error (shown at bottom), with the code here:
···
------------------------------
listOfThingsPlotted =
listOfLegendLabels =
for column in sorted(yValues):
temp = ax.fill_between(xValues, yValues[column], label=column)
listOfThingsPlotted.append(temp)
listOfLegendLabels.append(column)
legend = plt.legend(listOfThingsPlotted,listOfLegendLabels,bbox_to_anchor=(1.25, 1), shadow=True, fancybox=True)
------------------------------
Error:
------------------------------
Traceback (most recent call last):
File "/cms/cmsprod/bin/prodJobMonitorPlots_matplotlib.py", line 117, in <module>
plotStackedJobsVsTime(inputFile, outputFile, outputTitle)
File "/cms/cmsprod/bin/prodJobMonitorPlots_matplotlib.py", line 93, in plotStackedJobsVsTime
legend = plt.legend(listOfThingsPlotted,listOfLegendLabels,bbox_to_anchor=(1.25, 1), shadow=True, fancybox=True) # Make legend
File "/afs/hep.wisc.edu/cms/sw/python/x86/2.5.4/lib/python2.5/site-packages/matplotlib-0.99.1.1_r0-py2.5-linux-i686.egg/matplotlib/pyplot.py", line 2437, in legend
ret = gca().legend(*args, **kwargs)
File "/afs/hep.wisc.edu/cms/sw/python/x86/2.5.4/lib/python2.5/site-packages/matplotlib-0.99.1.1_r0-py2.5-linux-i686.egg/matplotlib/axes.py", line 4044, in legend
self.legend_ = mlegend.Legend(self, handles, labels, **kwargs)
File "/afs/hep.wisc.edu/cms/sw/python/x86/2.5.4/lib/python2.5/site-packages/matplotlib-0.99.1.1_r0-py2.5-linux-i686.egg/matplotlib/legend.py", line 304, in __init__
self._init_legend_box(handles, labels)
File "/afs/hep.wisc.edu/cms/sw/python/x86/2.5.4/lib/python2.5/site-packages/matplotlib-0.99.1.1_r0-py2.5-linux-i686.egg/matplotlib/legend.py", line 582, in _init_legend_box
handlebox.add_artist(handle)
File "/afs/hep.wisc.edu/cms/sw/python/x86/2.5.4/lib/python2.5/site-packages/matplotlib-0.99.1.1_r0-py2.5-linux-i686.egg/matplotlib/offsetbox.py", line 475, in add_artist
a.set_transform(self.get_transform())
AttributeError: 'NoneType' object has no attribute 'set_transform'