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 ------------------------------------------------------------------------- This SF.Net email is sponsored by the Moblin Your Move Developer's challenge Build the coolest Linux based applications with Moblin SDK & win great prizes Grand prize is a trip for two to an Open Source event anywhere in the world http://moblin-contest.org/redirect.php?banner_id=100&url=/ _______________________________________________ Matplotlib-users mailing list Matplotlib-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/matplotlib-users
