René's URL Explorer Experiment

{"@context":"https://schema.org","@type":"DiscussionForumPosting","headline":"Blank colorbars for high dynamic range LogNorm imshow plots","articleBody":"**Bug summary**\r\n\r\nWhen creating a LogNorm imshow plot with more than 9 orders of magnitude of dynamic range the automatically generated colorbar from plt.colorbar() has no automatically generated tick marks or labels.\r\n\r\n**Code for reproduction**\r\n\r\n\u003c!--A minimum code snippet required to reproduce the bug, also minimizing the number of dependencies required--\u003e\r\n\r\nThis generates a plot with colorbar tick labels\r\n\r\n```python\r\nimport numpy as np\r\n\r\nfrom matplotlib import pyplot as plt\r\nfrom matplotlib.colors import LogNorm\r\n\r\ndata = np.zeros((800, 800)) + 1\r\ndata[50, 51] = 1e9\r\n\r\nprint(np.log10(data.max()/data.min()))\r\n\r\nimage = plt.imshow(data, origin='lower', interpolation='nearest', norm=LogNorm())\r\nplt.colorbar(image)\r\n\r\nplt.savefig('labels.png')\r\n```\r\n\r\n![labels](https://user-images.githubusercontent.com/3126246/34186726-184f5a54-e4f3-11e7-86c9-28d0c8f405ec.png)\r\n\r\nWhile this script generates a plot with no colorbar tick labels:\r\n\r\n```python\r\nimport numpy as np\r\n\r\nfrom matplotlib import pyplot as plt\r\nfrom matplotlib.colors import LogNorm\r\n\r\ndata = np.zeros((800, 800)) + 1\r\ndata[50, 51] = 2e9\r\n\r\nprint(np.log10(data.max()/data.min()))\r\n\r\nimage = plt.imshow(data, origin='lower', interpolation='nearest', norm=LogNorm())\r\nplt.colorbar(image)\r\n\r\nplt.savefig('no-labels.png')\r\n```\r\n\r\n![no-labels](https://user-images.githubusercontent.com/3126246/34186748-3f70b6be-e4f3-11e7-9ebc-8c69e932d41c.png)\r\n\r\n\r\n**Expected outcome**\r\n\r\nI would expect the second plot to also have colorbar tick labels.\r\n\r\n**Matplotlib version**\r\n\u003c!--Please specify your platform and versions of the relevant libraries you are using:--\u003e\r\n  * Operating system: Mac OS High Sierra\r\n  * Matplotlib version: 2.1.1 (installed via pip)\r\n  * Matplotlib backend (`print(matplotlib.get_backend())`): MacOSX\r\n  * Python version: 3.6\r\n\r\n\u003c!--Please tell us how you installed matplotlib and python e.g., from source, pip, conda--\u003e\r\n\u003c!--If you installed from conda, please specify which channel you used if not the default--\u003e\r\n\r\n","author":{"url":"https://github.com/ngoldbaum","@type":"Person","name":"ngoldbaum"},"datePublished":"2017-12-20T01:32:33.000Z","interactionStatistic":{"@type":"InteractionCounter","interactionType":"https://schema.org/CommentAction","userInteractionCount":17},"url":"https://github.com/10051/matplotlib/issues/10051"}