Is there a particular name for bar plots, in which bars are rectangular, with unequal bases?

That is:

  • width represents size (e.g. population),
  • height represents intensive variable (e.g. CO$_2$ emission per capita),
  • area represents extensive variable (e.g. total CO$_2$ emission).

Example (from David JC MacKay, "Sustainable Energy - without the hot air", page 14):

CO2 emission rate by country

In the same vein: this and that. Another one: "Real GDP Per Capita and Shares of Global Population" (found here):

enter image description here

I find these plots immensely useful, as they show both the local effect (is a country particularly rich, polluting, militaristic...) and the global share (of economy/pollution/military power).

I have even made one: Research publications per capita? - Academia.SE. I care for its name both to search for examples, plotting libraries/functions etc, and to propagate this way of presenting data.

  • 1
    $\begingroup$ All bars are rectangular (quadrilateral with four right angles)! What's a little unusual here are the varying (unequal) bar widths. Plotting cumulative shares like this is perhaps more commonly done using a Lorenz curve, which in turn is a kind of P-P (probability-probability) plot. You have here discrete versions with several bars identified. I don't know that this has, or really needs, a distinctive name. Your second graph is closer to a Lorenz curve; the first has extra structure given by grouping. $\endgroup$
    – Nick Cox
    Jun 29 '15 at 13:17
  • $\begingroup$ @NickCox I missed "uneven base" (fixed). Thanks for brining Lorenz curve (I know it, but I was not thinking about it as bar plots from this question can, but don't have to be, ordered). $\endgroup$ Jun 29 '15 at 13:21
  • $\begingroup$ Small corrections: In English we would not say "uneven"; that's for surfaces not quite flat or smooth. It's Lorenz: Lorentz was a different person altogether. Key point: You are correct: bar charts with touching unequal width bars do not have to be ordered. But they are not of much use or interest without an ordering of some kind. $\endgroup$
    – Nick Cox
    Jun 29 '15 at 13:24
  • $\begingroup$ @NickCox Lorenz - fixed (I can never remember, same Schwar(t)z). Well, there are other orderings, which make sense (e.g. as in the example 1); or there may be no ordering if there are only a few values. Is "variable bases" OK? $\endgroup$ Jun 29 '15 at 13:31
  • 1
    $\begingroup$ Kaiser Fung points out the shortcomings of that GDP chart in his junkcharts blog and a follow-up post. $\endgroup$
    – xan
    Jun 30 '15 at 12:55

Apparently they are called cascade charts, see:

As a bonus, ggplot2: Variable Width Column Chart.

However, sometimes cascade chart is used as a synonymous of waterfall chart (which is a different thing from the discussed above), see e.g.:

In any case, judging for length I needed to get this answer, this name may be not that popular even among people creating similar bar plots (and perhaps a descriptive way may be better).

As was pointed out by @NickCox, if bars are sorted by their height, it is a discrete variant of the Lorenz curve.

  • 2
    $\begingroup$ I found three quite different meanings for waterfall plot or chart in a search a while back. Picturesque name, inconstant interpretation. $\endgroup$
    – Nick Cox
    Jun 29 '15 at 18:42

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.