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Radial Bar Charts – How would you improve this?

by on December 23, 2009

Recently, Jeff Heard was approached to convert a 3D Excel Spreadsheet into something more understandable, and allow comparison of columns for balance, comparison of third dimension alternates, comparison of rows for balance, and comparison of overall sums.  His solution (shown) : Radial Bar Charts.

Along the ring are the names of the columns of data in the spreadsheet. On each spoke are the rows in the two layers of the spreadsheet visualized as bar charts. Stretching counterclockwise are the bars for senior faculty. Stretching clockwise are the bars for graduate research assistants. In the center, visualized as bubbles of varying radii are the totals from both bar charts along the spoke. Note the light, thin rings connecting each bar. These are designed to draw a viewer’s eye around the chart, connecting bar to bar visually to inform the viewer that comparison is relevant.

Personally, I find the chart borderline incomprehensible.  Now, Jeff had limited time (only 5 days) and a rather impressive collection of requirements to meet, but the resulting chart seems to breakdown in several ways:

  • Too much data
  • Use of Circles to compare size.
  • Rotated fonts.. Anytime you have to write letters & numbers upside-down, you’ve done something wrong
  • Bar Lengths – are they radial? or length-based? eg, do the outer rings have a different scale than the inner rings?  It seems they are radial.  Look at the upper right section “Operations/Facilities”, and look at the inner dark-green bar valued 0.2, and a few bars up you see 0.18 .. The 0.18 bar appears larger than the 0.2, while it should be smaller.

For an example, quickly try to find the Graduate FTE’s in Research Department 2.   The Answer? 0.50 (I think, like I said it’s hard to read).

What do you think?  They say hindsight is 20/20, so how would you improve it?

via Radial Bar Charts | Hieroglyphics.