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From: Benjamin R. <ben...@ou...> - 2011-03-10 17:43:52
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On Thu, Mar 10, 2011 at 8:40 AM, Auré Gourrier <aur...@ya...>wrote: > Dear all, > > Once again, I turn for help. > I'm trying to plot a polar image using colormap values for the theta values > and increasing alpha values along the radius. > I do this using imshow passing the rgba tuple at each pixel position which > works very nicely with rectangular axes, but fails to display using polar > axes (see code below). > As usual, I've done a fair bit of digging to find where the problem is and > whether I could make out an alternate solution but haven't managed to come > through. I've tried using pcolormesh but I don't see how to pass the rgba > tuple > Can anyone point me in the right direction. > I'm using matplotlib 1.0.1 and Python 2.4 > > Cheers, > > Auré > > It appears that imshow() (and matshow()) do not support non-rectilinear axes. I don't know if this is a bug or if there is no way to make it support polar projections. Hopefully, someone else more knowledgable could chime in on this. I am also not exactly sure how to accomplish what you want using pcolor. A really slow, painful way would be to pcolor each row with the rest masked out, setting the alpha value for that row. I have long wondered if the alpha kwarg in various functions could be improved by allowing array values and take advantage of numpy broadcasting. Ben Root |