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[Bug] Error: 'PathCollection' object has no attribute 'do_3d_projection' when doing contourf in 3d with extend = 'both' #21016

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heavysink opened this issue Sep 8, 2021 · 3 comments · Fixed by #21026
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[Bug] Error: 'PathCollection' object has no attribute 'do_3d_projection' when doing contourf in 3d with extend = 'both' #21016

heavysink opened this issue Sep 8, 2021 · 3 comments · Fixed by #21026
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status: confirmed bug topic: mplot3d
Milestone
v3.5.0

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@heavysink
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heavysink commented Sep 8, 2021 •
edited by dstansby
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Bug summary

When doing contourf in 3D with given levels and extend = 'both', matplotlib will raise error 'PathCollection' object has no attribute 'do_3d_projection'.

Code for reproduction

from mpl_toolkits.mplot3d import axes3d
import matplotlib.pyplot as plt
from matplotlib import cm
import numpy as np

ax = plt.figure().add_subplot(projection='3d')
X, Y, Z = axes3d.get_test_data(0.1)
levels = np.arange(-70.0,70.0,1.0)

# Plot projections of the contours for each dimension.  By choosing offsets
# that match the appropriate axes limits, the projected contours will sit on
# the 'walls' of the graph
cset = ax.contourf(X, Y, Z, zdir='z', offset=-100, levels = levels, extend='both', cmap=cm.coolwarm)

ax.set_xlim(-40, 40)
ax.set_ylim(-40, 40)
ax.set_zlim(-100, 100)

ax.set_xlabel('X')
ax.set_ylabel('Y')
ax.set_zlabel('Z')

plt.show()

Actual outcome

---------------------------------------------------------------------------
AttributeError                            Traceback (most recent call last)
/usr/lib/python3.9/site-packages/IPython/core/formatters.py in __call__(self, obj)
    339                 pass
    340             else:
--> 341                 return printer(obj)
    342             # Finally look for special method names
    343             method = get_real_method(obj, self.print_method)

/usr/lib/python3.9/site-packages/IPython/core/pylabtools.py in <lambda>(fig)
    248 
    249     if 'png' in formats:
--> 250         png_formatter.for_type(Figure, lambda fig: print_figure(fig, 'png', **kwargs))
    251     if 'retina' in formats or 'png2x' in formats:
    252         png_formatter.for_type(Figure, lambda fig: retina_figure(fig, **kwargs))

/usr/lib/python3.9/site-packages/IPython/core/pylabtools.py in print_figure(fig, fmt, bbox_inches, **kwargs)
    132         FigureCanvasBase(fig)
    133 
--> 134     fig.canvas.print_figure(bytes_io, **kw)
    135     data = bytes_io.getvalue()
    136     if fmt == 'svg':

/usr/lib/python3.9/site-packages/matplotlib/backend_bases.py in print_figure(self, filename, dpi, facecolor, edgecolor, orientation, format, bbox_inches, pad_inches, bbox_extra_artists, backend, **kwargs)
   2228                        else suppress())
   2229                 with ctx:
-> 2230                     self.figure.draw(renderer)
   2231 
   2232             if bbox_inches:

/usr/lib/python3.9/site-packages/matplotlib/artist.py in draw_wrapper(artist, renderer, *args, **kwargs)
     72     @wraps(draw)
     73     def draw_wrapper(artist, renderer, *args, **kwargs):
---> 74         result = draw(artist, renderer, *args, **kwargs)
     75         if renderer._rasterizing:
     76             renderer.stop_rasterizing()

/usr/lib/python3.9/site-packages/matplotlib/artist.py in draw_wrapper(artist, renderer, *args, **kwargs)
     49                 renderer.start_filter()
     50 
---> 51             return draw(artist, renderer, *args, **kwargs)
     52         finally:
     53             if artist.get_agg_filter() is not None:

/usr/lib/python3.9/site-packages/matplotlib/figure.py in draw(self, renderer)
   2778 
   2779             self.patch.draw(renderer)
-> 2780             mimage._draw_list_compositing_images(
   2781                 renderer, self, artists, self.suppressComposite)
   2782 

/usr/lib/python3.9/site-packages/matplotlib/image.py in _draw_list_compositing_images(renderer, parent, artists, suppress_composite)
    130     if not_composite or not has_images:
    131         for a in artists:
--> 132             a.draw(renderer)
    133     else:
    134         # Composite any adjacent images together

/usr/lib/python3.9/site-packages/matplotlib/artist.py in draw_wrapper(artist, renderer, *args, **kwargs)
     49                 renderer.start_filter()
     50 
---> 51             return draw(artist, renderer, *args, **kwargs)
     52         finally:
     53             if artist.get_agg_filter() is not None:

/usr/lib/python3.9/site-packages/mpl_toolkits/mplot3d/axes3d.py in draw(self, renderer)
    483                                 for axis in self._get_axis_list()) + 1
    484             for i, col in enumerate(
--> 485                     sorted(self.collections,
    486                            key=do_3d_projection,
    487                            reverse=True)):

/usr/lib/python3.9/site-packages/mpl_toolkits/mplot3d/axes3d.py in do_3d_projection(artist)
    476                     "do_3d_projection() was deprecated in Matplotlib "
    477                     "%(since)s and will be removed %(removal)s.")
--> 478                 return artist.do_3d_projection(renderer)
    479 
    480             # Calculate projection of collections and patches and zorder them.

AttributeError: 'PathCollection' object has no attribute 'do_3d_projection'

Expected outcome

Removing extend='both' the code works fine

2021-09-08_01-58

Operating system

Arch

Matplotlib Version

3.4.2

Matplotlib Backend

module://matplotlib_inline.backend_inline

Python version

python 3.9.6

Jupyter version

3.1.6

Other libraries

No response

Installation

Linux package manager (Debian/Fedora/etc.)

Conda channel

No response
@dstansby
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dstansby commented Sep 8, 2021

Weird... this is broken at least as far back as 3.1.x, so I suspect has always been broken. I've had a bit of a dig, but not having much luck finding the root cause.

@QuLogic
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QuLogic commented Sep 9, 2021

contourf uses a PathCollection, contour uses a LineCollection, though both now use a PathCollection on master. The Axes3D attempts to convert a filled contour to 3D as a PolyCollection; this apparently does nothing with a PathCollection. I don't know how long that has been out of sync. Similarly, unfilled contours on master should be broken since they've changed types, but I guess it happens to work because those are at least closer types.

@QuLogic
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QuLogic commented Sep 9, 2021 •
edited
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OK, types aside, it is able to convert them reasonably well. The problem is here:

matplotlib/lib/mpl_toolkits/mplot3d/axes3d.py

Lines 2070 to 2076 in ce9a7b1

def add_contourf_set(self, cset, zdir='z', offset=None):
zdir = '-' + zdir
for z, linec in zip(cset.levels, cset.collections):
if offset is not None:
z = offset
art3d.poly_collection_2d_to_3d(linec, z, zdir=zdir)
linec.set_sort_zpos(z)

For a filled contour (with extend?), there is one more collection than there are levels, so the last one is not converted to 3D.

@dstansby dstansby mentioned this issue Sep 9, 2021
Merged
7 tasks
@QuLogic QuLogic added this to the v3.5.0 milestone Sep 27, 2021
@krzywon krzywon mentioned this issue Nov 29, 2021
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status: confirmed bug topic: mplot3d
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Place 3D contourf patches between levels dstansby/matplotlib
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@QuLogic @dstansby @heavysink