Wednesday, August 31, 2011

Map Visualization Fail Series: #1 Using Hash Lines Confuses the Story

This map recently came across in a tweet and tells the story of the 12 month Housing Price Index change by state. I  had a difficult time wrapping my brain around it. Although this map tells a story it was difficult to read and I found it a great example of what not to do when creating visualizations for a consumer audience.

This map does have some good points to it, the first being that it is telling a story and without a story the map is useless. The second point is the use of minimal data breaks. It is difficult for the brain to consume much more than five so keeping it to five or less is a good rule of thumb. The third point is a easy to understand legend which also makes the map more usable. The problem I have is with the use of hash line fills and the choice of color to differentiate the breaks. These combinations made me rely on the legend over and over again to determine what I was looking at. This back and forth added noise to the story and added an unneeded challenge to pull out the information.

How could this map have been better? To start use colors that make since; green = good red = bad or blue = cool and red = hot. Everyone understands these colors and the brain can quickly determine what state a feature is in just by these two colors. Next use intensity of color to show the depth of bad or good. Use dark green for the values that are showing the best and graduate to a lighter green as the data goes neutral. It really is that simple. Do away with hash lines, they are confusing and make the reader jump to the legend to remind the brain what it is looking at. While some of your readers will tolerate this most will not and the message will be lost.

Keeping the map simple without a lot of distraction will allow the story to jump out at the reader and get your message across.

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Map Visualization Fail Series: #1 Using Hash Lines Confuses the Story! A Post By - @SkipCody #GIS #MAP

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