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{"@context":"https://schema.org","@type":"DiscussionForumPosting","headline":"[Bug]: pcolormesh doesn't allow shading = 'flat' in the option","articleBody":"### Bug summary\r\n\r\nIn the code below I tried to use pcolormesh to make a grid intensity plot. When thethe default option shading = 'flat' was written in the method, the code couldn't run. Either when I omitted writing this default configuration in the code or when I changed the code to shading = 'nearest', or other listed options in the [documentation](https://matplotlib.org/devdocs/api/_as_gen/matplotlib.axes.Axes.pcolormesh.html), the code worked smoothly. Note that the shape of x, y and z matched but the error was trying to say they didn't match.\r\n\r\n### Code for reproduction\r\n\r\n```python\r\nimport matplotlob.pyplot as plt\r\nimport numpy as np\r\n\r\nx, y = np.meshgrid(np.arange(5), np.arange(3))\r\nz = x + y\r\nprint(np.shape(z))\r\nprint(np.shape(x))\r\nprint(np.shape(y))\r\nplt.pcolormesh(x, y, z, shading = 'flat')\r\n```\r\n\r\n\r\n### Actual outcome\r\n\r\n(3, 5)\r\n(3, 5)\r\n(3, 5)\r\n---------------------------------------------------------------------------\r\nTypeError                                 Traceback (most recent call last)\r\nCell In [32], line 13\r\n     11 print(np.shape(x))\r\n     12 print(np.shape(y))\r\n---\u003e 13 plt.pcolormesh(x, y, z, shading = 'flat')\r\n\r\nFile /opt/homebrew/lib/python3.10/site-packages/matplotlib/pyplot.py:2728, in pcolormesh(alpha, norm, cmap, vmin, vmax, shading, antialiased, data, *args, **kwargs)\r\n   2723 @_copy_docstring_and_deprecators(Axes.pcolormesh)\r\n   2724 def pcolormesh(\r\n   2725         *args, alpha=None, norm=None, cmap=None, vmin=None,\r\n   2726         vmax=None, shading=None, antialiased=False, data=None,\r\n   2727         **kwargs):\r\n-\u003e 2728     __ret = gca().pcolormesh(\r\n   2729         *args, alpha=alpha, norm=norm, cmap=cmap, vmin=vmin,\r\n   2730         vmax=vmax, shading=shading, antialiased=antialiased,\r\n   2731         **({\"data\": data} if data is not None else {}), **kwargs)\r\n   2732     sci(__ret)\r\n   2733     return __ret\r\n\r\nFile /opt/homebrew/lib/python3.10/site-packages/matplotlib/__init__.py:1414, in _preprocess_data.\u003clocals\u003e.inner(ax, data, *args, **kwargs)\r\n   1411 @functools.wraps(func)\r\n   1412 def inner(ax, *args, data=None, **kwargs):\r\n   1413     if data is None:\r\n-\u003e 1414         return func(ax, *map(sanitize_sequence, args), **kwargs)\r\n   1416     bound = new_sig.bind(ax, *args, **kwargs)\r\n   1417     auto_label = (bound.arguments.get(label_namer)\r\n   1418                   or bound.kwargs.get(label_namer))\r\n\r\nFile /opt/homebrew/lib/python3.10/site-packages/matplotlib/axes/_axes.py:6064, in Axes.pcolormesh(self, alpha, norm, cmap, vmin, vmax, shading, antialiased, *args, **kwargs)\r\n   6061 shading = shading.lower()\r\n   6062 kwargs.setdefault('edgecolors', 'none')\r\n-\u003e 6064 X, Y, C, shading = self._pcolorargs('pcolormesh', *args,\r\n   6065                                     shading=shading, kwargs=kwargs)\r\n   6066 coords = np.stack([X, Y], axis=-1)\r\n   6067 # convert to one dimensional array\r\n\r\nFile /opt/homebrew/lib/python3.10/site-packages/matplotlib/axes/_axes.py:5574, in Axes._pcolorargs(self, funcname, shading, *args, **kwargs)\r\n   5572 if shading == 'flat':\r\n   5573     if (Nx, Ny) != (ncols + 1, nrows + 1):\r\n-\u003e 5574         raise TypeError('Dimensions of C %s are incompatible with'\r\n   5575                         ' X (%d) and/or Y (%d); see help(%s)' % (\r\n   5576                             C.shape, Nx, Ny, funcname))\r\n   5577 else:    # ['nearest', 'gouraud']:\r\n   5578     if (Nx, Ny) != (ncols, nrows):\r\n\r\nTypeError: Dimensions of C (3, 5) are incompatible with X (5) and/or Y (3); see help(pcolormesh)\r\n\r\n### Expected outcome\r\n\r\nNo error\r\n\r\n### Additional information\r\n\r\nI think the problem is in the section when shading = 'flat' in line 5574 in _axes.py as shown in the error message\r\n\r\n### Operating system\r\n\r\nOS 12.4\r\n\r\n### Matplotlib Version\r\n\r\n3.5.3\r\n\r\n### Matplotlib Backend\r\n\r\n_No response_\r\n\r\n### Python version\r\n\r\n_No response_\r\n\r\n### Jupyter version\r\n\r\n6.4.12\r\n\r\n### Installation\r\n\r\npip","author":{"url":"https://github.com/casesyh","@type":"Person","name":"casesyh"},"datePublished":"2022-12-09T18:15:03.000Z","interactionStatistic":{"@type":"InteractionCounter","interactionType":"https://schema.org/CommentAction","userInteractionCount":11},"url":"https://github.com/24678/matplotlib/issues/24678"}