Sunday, April 20, 2014

Good visualization by National Geographic

Sunday is the perfect day to enjoy some good journalism and graphics at leisure. This morning, right after I finished breezing through the humongous Sunday edition of The New York Times*, I went back to an interactive visualization about exoplanets that I discovered yesterday. It was designed by National Geographic's Xaquín G.V. and John Tomanio. I hope that Juan Velasco will soon write about how it was made.

Xaquin's and John's graphic is elegant and fun to play with. Notice that you can toggle between a logarithmic and a linear scale on the Y-axis, which is a great idea. Perhaps my only complaint is that the graphic cannot be seen in its entirety unless that you have a large screen (I do.) Otherwise, you'll need to scroll.

Also, I think that they are burying the lede a bit, but this may be just me. This is one of the most interesting points of the graphic, but it's shown at the end of the text box on the right, where it may easily go unnoticed:

"The logarithmic scale used initially here allows for an easier comparison of the exoplanets. The linear scale shows how shallow the habitability zone is."

Nice one, in any case!

*Tossing the Sports and Styles sections aside; paying attention at the news, Book Review, Sunday Review, and Business pages; keeping the magazine for tomorrow; etc.


  1. (I commented on facebook already, but Alberto asked me to bring it over here, so, here we go:)

    I think it is a nice approach, but to me the graphic seems a bit unfinished - here are some of the things I would like to put up for debate:
    - The earth as the central reference point could play a much more expressed role as a visual anchor.
    - The black outlined box is a quite weak choice, from a visual design point of view.
    - In a scatterplot, one would expect (0,0) to be in the bottom left corner. I can see how the inversion of the mass axis sort of helps the graphic, but the inverted horizontal temperature scale is quite confusing IMO and I cannot see the benefit.
    - Also, the circle sizes seem very large given the high number of data points and the fact that the size encoding is redundant with the vertical position.

    So, overall, honestly, I think it could have been much stronger with some extra effort ("the second 80%" :)

    The other thing: I am not 100% sure the main story actually checks out, in a sense that it's strictly a "box" of inhabitable planets. I could imagine this "box" of habitability has pretty fuzzy borders in reality and might not be as neatly shaped as the graphic makes it look. (Expert opinions welcome - I am just speculating :)

  2. Hi, Moritz,
    the inverted horizontal temperature actually shows the distance from the star: the hotter the planet, the closer to its star. So, this axis, read from left to right, shows the distance to the star. If they did it from low to high temperature, as you suggested, you would end with the closest planets at the right side of the axis, and that is not common in astronomic illustrations.
    The size encoding is not redundant with the vertical position, because vertical positions shows mass, not size.
    The “habitability” of a planet is defined by its distance from the star (from x1 to x2) and by its mass (from y1 to y2, supposing it is not a Gas Giant). So, if you consider both measures, you get a pretty sharpen box.
    Here is a good table about this:
    The “Planetary Habitability Laboratory” in Arecibo has a lot of good images and data:

    1. Here is the correct link to PHL, with all the media: