Monday, December 22, 2008

Useless Map Fades to Gray

I want to be fair to the Wall Street Journal but sometimes I'm just left scratching my head. In an article in today's WSJ, a thematic map of the median household income in and around the Chicago area was used to show the high income areas affected by the routing of a freight rail line. Canadian National Railway purchased a suburban rail line that they wanted to use for freight to bypass the congested lines through downtown Chicago.

In fairness, I think the map enhanced the story. The problem was that you just could not read it. Once again, a shaded gray thematic doesn't really work for a print newspaper. Though the WSJ limited the gray tones to only four, the tones were too faded. And it took me almost five minutes to actually see that the rail line was overlayed on the map itself. It was not noted in the legend and I can only assume that they thought it was obvious. It was not.

Now, unless you are faily familiar with thematic maps and you can discern spatial patterns, the fact that the rail line does indeed meander through some of the high income ZIP codes, you'd miss the entire point of the map. Neither were some of the more recognizable high income towns denoted on the map like Lake Forrest and Barrington, which would have help me understand where the rail line was routed. So, the town names were missing, the political boundaries of the thematic were not explained, and the rail line itself was fading into the background. Why bother with the map at all?

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