Mixed feelings about a series of lovely maps

I know, I know, I've complained before—and will keep complaining—about thematic maps that lack legends—a trend that seems to be gaining traction in news visualization,—but allow me to recommend this recent NYT story about donors to Democratic primary candidates, which showcases plenty of them.

I must admit the maps look lovely, and they do help spot regional patterns so, to certain extent, they work. It's just that, as a reader, I feel very uneasy when designers don't tell me what range of quantities shades of color represent. Moreover, as a visualization designer myself, I think that maps without legends are similar to graphs without X/Y-scales, something that may undermine not only the effectiveness of the graphic—you can see more and less, but not get even the faintest idea of how much more or less,—but also trust.

My favorite maps in the story are the smaller ones at the bottom of it: