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年8月6日 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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