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Johannes Hüsing

You get the picture at a better resolution at


Unfortunately, I think the colour scale is reversed. Red typically has a negative connotation (at least in Western cultures) and yet here it represents the closest points.

Robert Kosara

Depends on how you look at it - the red could also show you the "hot" areas, i.e., where you want to live to get to that building quickly.

And while this is a nice map, I think the color scale is the usual mistake. It goes from dark red to bright yellow to greenish to dark blue. There are very clear lines between red and yellow, and yellow and blue, while there is practically no variation within those colors.

The difference in brightness also makes the contrast of the iso lines vary a lot, making them almost invisible on the yellow. It would have made a lot more sense to have only a small number of colors, and have them change at every iso line, thus creating little islands of consistent color, with lines around them. That would also reflect the limited quality and resolution of the data.

The color scale should either be isoluminant or change from bright to dark or the other way around, but not go dark-bright-dark. Also, a legend is missing.

If I were trying to pick a fight, I would insinuate at this point that the fact that Kaiser knows the maker of this map clouded his judgment. But I'm not in a fighting mood today ;)

So let me close by agreeing to the statement that we have access to so much data today we don't even know, and that the only way to make sense of it all is to visualize it.


On colors, the authors had this to say: "We choose the colours according to a standard scale, but adjust the colours using histogram equalisation so that each colour covers approximately the same area of map."

Since nothing else they did is "standard" fare, they already tacitly acknowledged the shortcoming.

The point of this post, though, is to provide a rare glimpse into the process of transforming large amounts of data into a form that can be easily graphed, and utilized to solve a practical problem!

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