René's URL Explorer Experiment

{"@context":"https://schema.org","@type":"DiscussionForumPosting","headline":"LogNorm on empty image fails","articleBody":"### Bug report\r\n\r\n**Bug summary**\r\n\r\n`ax.imshow([[]], norm=LogNorm())` does not work but `ax.imshow([[]])` does.\r\n\r\n**Code for reproduction**\r\n\r\n```python\r\nimport matplotlib.pyplot as plt\r\nfrom matplotlib.colors import LogNorm\r\nfig, ax = plt.subplots(1, 1)\r\nax.imshow([[]])  # doesn't fail\r\nax.imshow([[]], norm=LogNorm)  # fails\r\n```\r\n\r\n**Actual outcome**\r\n\r\n```\r\n---------------------------------------------------------------------------\r\nValueError                                Traceback (most recent call last)\r\n\u003cipython-input-4-dc293e10dd21\u003e in \u003cmodule\u003e()\r\n----\u003e 1 ax.imshow([[]], norm=LogNorm())\r\n\r\n/home/christopher/mc/envs/dp_dev/lib/python3.5/site-packages/matplotlib/__init__.py in inner(ax, *args, **kwargs)\r\n   1896                     warnings.warn(msg % (label_namer, func.__name__),\r\n   1897                                   RuntimeWarning, stacklevel=2)\r\n-\u003e 1898             return func(ax, *args, **kwargs)\r\n   1899         pre_doc = inner.__doc__\r\n   1900         if pre_doc is None:\r\n\r\n/home/christopher/mc/envs/dp_dev/lib/python3.5/site-packages/matplotlib/axes/_axes.py in imshow(self, X, cmap, norm, aspect, interpolation, alpha, vmin, vmax, origin, extent, shape, filternorm, filterrad, imlim, resample, url, **kwargs)\r\n   5132             im.set_clim(vmin, vmax)\r\n   5133         else:\r\n-\u003e 5134             im.autoscale_None()\r\n   5135         im.set_url(url)\r\n   5136 \r\n\r\n/home/christopher/mc/envs/dp_dev/lib/python3.5/site-packages/matplotlib/cm.py in autoscale_None(self)\r\n    343         if self._A is None:\r\n    344             raise TypeError('You must first set_array for mappable')\r\n--\u003e 345         self.norm.autoscale_None(self._A)\r\n    346         self.changed()\r\n    347 \r\n\r\n/home/christopher/mc/envs/dp_dev/lib/python3.5/site-packages/matplotlib/colors.py in autoscale_None(self, A)\r\n    962         A = ma.masked_less_equal(A, 0, copy=False)\r\n    963         if self.vmin is None:\r\n--\u003e 964             self.vmin = ma.min(A)\r\n    965         if self.vmax is None:\r\n    966             self.vmax = ma.max(A)\r\n\r\n/home/christopher/mc/envs/dp_dev/lib/python3.5/site-packages/numpy/ma/core.py in min(obj, axis, out, fill_value, keepdims)\r\n   6300 \r\n   6301     try:\r\n-\u003e 6302         return obj.min(axis=axis, fill_value=fill_value, out=out, **kwargs)\r\n   6303     except (AttributeError, TypeError):\r\n   6304         # If obj doesn't have a min method, or if the method doesn't accept a\r\n\r\n/home/christopher/mc/envs/dp_dev/lib/python3.5/site-packages/numpy/ma/core.py in min(self, axis, out, fill_value, keepdims)\r\n   5470         if out is None:\r\n   5471             result = self.filled(fill_value).min(\r\n-\u003e 5472                 axis=axis, out=out, **kwargs).view(type(self))\r\n   5473             if result.ndim:\r\n   5474                 # Set the mask\r\n\r\n/home/christopher/mc/envs/dp_dev/lib/python3.5/site-packages/numpy/core/_methods.py in _amin(a, axis, out, keepdims)\r\n     27 \r\n     28 def _amin(a, axis=None, out=None, keepdims=False):\r\n---\u003e 29     return umr_minimum(a, axis, None, out, keepdims)\r\n     30 \r\n     31 def _sum(a, axis=None, dtype=None, out=None, keepdims=False):\r\n\r\n```\r\n\r\n**Expected outcome**\r\nSimilar to the not log norm version display an empty plot.\r\n\r\n**Matplotlib version**\r\n  * Operating System: Ubuntu 16.04\r\n  * Matplotlib Version: matplotlib                2.0.2               np111py35_0    conda-forge\r\n  * Python Version: 3.5\r\n","author":{"url":"https://github.com/CJ-Wright","@type":"Person","name":"CJ-Wright"},"datePublished":"2017-09-17T00:39:33.000Z","interactionStatistic":{"@type":"InteractionCounter","interactionType":"https://schema.org/CommentAction","userInteractionCount":0},"url":"https://github.com/9194/matplotlib/issues/9194"}