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A reader sent over another example of an optical illusion that chart designers should think about. Here's a 3D column chart:
And the illusion:
Posted on Sep 25, 2012 at 08:15 AM | Permalink
I don't get it. What's the illusion? And what does it have to do with the chart?
Sep 25, 2012 at 12:23 PM
I don't get it either. But I'm glad someone else is with me on this :)
Sep 25, 2012 at 03:52 PM
Maybe the illusion is that the front and back bars are actually the same height but we think the back one is taller.
Sep 25, 2012 at 06:35 PM
Think its the fact that in the top illusion, as there are only two lines, its clear that the top and bottom one line up (apart from the break in the middle due to the white area), however, in the image below, with two lines below the white area, its not easy to tell which of the two lines line up with the one above.
The eye isnt good at picking up small differences of this sort
Sep 26, 2012 at 04:34 AM
Exactly. Looking at the chart, are you able to tell whether the purple bars are the same height or if the front one is shorter than that back one?
Sep 26, 2012 at 03:12 PM
I am very thankful to all your team for sharing such inspirational information.
John Sheldon |
Oct 10, 2012 at 06:30 AM
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