No michael, that is what I was suggesting. Shame it doesn't work.
I'm looking at using Enthoughts Chaco to do it. It's takes a bit more to get
it doing what I want though, and I don't know if it does alpha transparency
at all.
Thanks for your help.
Pete
2008/8/6 Michael Droettboom <[EMAIL PROTECTED]>
> It doesn't seem to matter whether the filled contours are drawn with edges
> or not -- the cuts are still visible because they're caused by over-drawing
> of the fill. (You can set linewidth=0 to try this.) But maybe I
> misunderstand your question.
>
> Cheers,
> Mike
>
>
> kippertoffee wrote:
>
>> Thank you for your reply Michael.
>>
>> Is it possible to make the lines in the contourf plot completely
>> transparent
>> using an alpha setting? That would make a reasonable workaround as I
>> intend
>> to overlay black contours anyway.
>>
>> I've had a look at the source but it is way beyond me; I am a mere
>> dabbler.
>>
>> Cheers,
>> Pete.
>>
>>
>> Michael Droettboom-3 wrote:
>>
>>
>>> This is a known issue with the contouring code. It's borrowed from an
>>> earlier plotting package called GIST, and assumes that the renderer can not
>>> handle compound polygons (for example, donut-shaped, with both an inner and
>>> outer edge). So instead, it draws "cuts" that go from the inner to the
>>> outer edge. When anti-aliasing is turned on, there is a slight overlap or
>>> "drawing twice" along this edge which creates what looks like a line.
>>> Unfortunately, this can't be remedied by plotting the contour fills and
>>> then plotting the contour edges over top (as is done is contourf_demo.py).
>>>
>>> As of matplotlib 0.98.x, matplotlib itself can handle compound paths, so
>>> we no longer need the cuts. I've made a few attempts at updating the
>>> contouring code to avoid them, but got nowhere. The contouring code is very
>>> opaque, almost magical code, and most who've dared to go in have barely made
>>> it out alive... ;) That said, a fresh pair of eyes may have what it
>>> takes...
>>>
>>> As for a workaround, you could render your contour as opaque, save that
>>> out as an image and read it back in. The code to do that won't be pretty,
>>> but it just might work.
>>>
>>> Cheers,
>>> Mike
>>>
>>> kippertoffee wrote:
>>>
>>>
>>>> Hello,
>>>>
>>>> I am attempting to overlay a filled contour over a custom image.
>>>>
>>>> I have managed to get something basic working, but i have encountered a
>>>> problem:
>>>>
>>>> When the contourf plot is set to semi-transparent there are visible
>>>> lines
>>>> joining the bottom of the plot and the filled contour edges. I have
>>>> attached
>>>> an image of the plot.
>>>>
>>>> http://img232.imageshack.us/my.php?image=spambs6.png spam.png
>>>> The code i have used is below; please bear in mind I am not a
>>>> programmer,
>>>> so
>>>> if the code seems botched, that's because it is.
>>>>
>>>> ###############################
>>>>
>>>> import matplotlib.pyplot as plt
>>>> from pylab import *
>>>> try:
>>>> import Image
>>>> except ImportError, exc:
>>>> raise SystemExit("PIL must be installed to run this example")
>>>>
>>>> lena = Image.open('lena.jpg')
>>>> dpi = rcParams['figure.dpi']
>>>> figsize = lena.size[0]/dpi, lena.size[1]/dpi
>>>>
>>>> fig = plt.figure(figsize=figsize)
>>>> #fig.patch.set_alpha(0.5)
>>>> ax = fig.add_subplot(111)
>>>> #ax.patch.set_alpha(0.5)
>>>>
>>>> ax.imshow(lena, origin='lower')
>>>>
>>>> ax.contourf(z2,[10,15,20,25,30,35,40,45,50,55,60,65],alpha=0.7)
>>>> show()
>>>> ############################
>>>>
>>>>
>>>> Can anyone help me with this problem?
>>>>
>>>> Thanks for reading,
>>>> Pete.
>>>>
>>>>
>>>
>>>
>>>
>>
>>
>>
>
> --
> Michael Droettboom
> Science Software Branch
> Operations and Engineering Division
> Space Telescope Science Institute
> Operated by AURA for NASA
>
>
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