Default style proposal: outward tick marks

I would like to propose making tick marks point outward by default (and for the 2.0 release). The idea for this comes from William Cleveland’s Elements of Graphing Data. I quote directly from him:

…tick marks should point outward. This format prevents data from being obscured (page 33)

The idea is really simple. Data belongs on the inside of the axes frame. If your tick marks point inwards, there is a good chance that the tick marks and data will interfere. This type of interference happens often in practice with dense amounts of data in line/scatter plots and with all kinds of color/surface plots. Here is a simple example:

The tick marks on a a default styled pcolor plot are almost impossible to see along some borders:

screen shot 2015-06-07 at 5 40 44 pm

The tick marks outwards become extremely helpful and visible:

screen shot 2015-06-07 at 5 40 50 pm

Cleveland’s way of describing this choice also helps me to understand the default visual styling of ggplot2 and seaborn, which use a) no tick marks and b) light grid lines against a grey bg. This is simply a different way of providing the visual guides for plots that don’t interfere with the data itself. The other option for the defaults would be to move in this direction (no tick marks with light grid lines on a grey bg), but I think that is probably too much change for the defaults.

Author: Fantashit

1 thought on “Default style proposal: outward tick marks

  1. FWIW, I was surprised today to see this new default, and am very much against it. While I can see situations where this can be useful, the following simple example is in my opinion worse than before:


    I think what bugs me is the outward ticks on the top and right axes. Many of the examples I’ve found that look ok with outward ticks have ticks only on the left and bottom axes and no axes on the top and right. I don’t think mixing the full axes box and outward ticks works. I’m not expecting the default to be changed back of course, but just wanted to make sure I voiced an opinion as a user, in case others feel the same.

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