René's URL Explorer Experiment

{"@context":"https://schema.org","@type":"DiscussionForumPosting","headline":"Add additional minor labels in log axis with a span less than two decades","articleBody":"For plots with log axis that have limits of the order or less than two decades, only one label is shown:\n![log_labels](https://cloud.githubusercontent.com/assets/576258/9082131/c84ce962-3b59-11e5-80c3-f12b85f16ff5.png)\n\nWhich does not give a very good idea of the values of the x axis. Adding labels to the minor ticks results in a mess, including non-helpful labels such as `10^{4.30}`:\n\n```\nax.xaxis.set_minor_formatter(ticker.LogFormatterMathtext(labelOnlyBase=False))\n```\n\n![log_labels_minor_logformattermathtext](https://cloud.githubusercontent.com/assets/576258/9082178/1e9f177c-3b5a-11e5-815a-a73d8bcdc33f.png)\n\nAnd limiting them at `[2,5]*base**i` results in losing all other minor ticks:\n\n```\nax.xaxis.set_minor_locator(ticker.LogLocator(subs=[2,5]))\n```\n\n![log_labels_minor_at_125_logformattermathtext](https://cloud.githubusercontent.com/assets/576258/9082194/471819ec-3b5a-11e5-8a89-22c23e2f2476.png)\n\nThe decimals in the exponent can be resolved using LogFormatter, but it is not a nice representation for axis and requires changing the major formatter to match:\n\n```\nax.xaxis.set_minor_formatter(ticker.LogFormatter(labelOnlyBase=False))\nax.xaxis.set_major_formatter(ticker.LogFormatter())\n```\n\n![log_labels_minor_at_125_logformatter](https://cloud.githubusercontent.com/assets/576258/9082286/df6bfcfe-3b5a-11e5-892f-6958e5399f7e.png)\n\nFinally, the only way to get them in a consistent manner with the major tick labels, while preserving all minor ticks, is to set them manually, which is far from ideal:\n\n```\nax.xaxis.set_ticklabels([r'$2\\times10^4$','','',r'$5\\times10^4$','','','','', \n        r'$2\\times 10^4$','','',r'$5\\times10^4$','','','','',\n        r'$2\\times 10^5$','','',r'$5\\times10^5$','','','','',\n        ],minor=True)\n```\n\n![log_labels_minor_at_125_manual_labels](https://cloud.githubusercontent.com/assets/576258/9082304/055831b2-3b5b-11e5-94fe-83cc4a2c92ff.png)\n\nI think that there should be a `LogFormatterMathtext` with a `subs` options like the locator, and an option to factors instead of decimal exponents. I will take a look at the `LogFormatterMathtext` and try to modify it in the following days. If it looks good, I would propose to switch to it automatically for axis spanning less than two decades.\n\nNote that this issue has been reported in [a stackoverflow question](http://stackoverflow.com/questions/17165435/matplotlib-show-labels-for-minor-ticks-also) where a custom formatter is proposed as an answer.\nThis is somewhat related to the issue #4730 because the lack of labels is particularly noticeable when the axis is around 0.1,1,10, where it would make a lot of sense to have labels at [0.1,0.2,2,5,20,50]. \n","author":{"url":"https://github.com/zblz","@type":"Person","name":"zblz"},"datePublished":"2015-08-05T09:21:09.000Z","interactionStatistic":{"@type":"InteractionCounter","interactionType":"https://schema.org/CommentAction","userInteractionCount":6},"url":"https://github.com/4867/matplotlib/issues/4867"}