News Cut: November 22, 2010 Archive

A visualization of changing American politics

Posted at 1:15 PM on November 22, 2010 by Bob Collins (1 Comments)
Filed under: Politics

Duke University PhD candidate David Sparks has developed a fascinating county-level look at the changing politics of America.

It's a great reminder that what you think is permanent in politics, seldom is.

On his Web site, Sparks writes:

This animated interpretation accentuates certain phenomena: the breadth and duration of support for Roosevelt, the shift from a Democratic to a Republican South, the move from an ostensibly east-west division to the contemporary coasts-versus-heartland division, and the stability of the latter.

More broadly, this video is a reminder that what constitutes "politics as usual" is always in flux, shifting sometimes abruptly. The landscape of American politics is constantly evolving, as members of the two great parties battle for electoral supremacy.

But maybe it's not what Sparks thinks it is. A commenter writes:

First, I like the subject and the attempt. Second, big trouble always lurks when spatial data tied to a geographic coordinate system ( λ , φ ) are treated as if they are plotted on a Cartesian grid ( x, y ). Above and beyond the conspicuous distortions in your state shapes and sizes (the Mercator class of map projections creates larger distortions with increasing distance from the equator), your linear interpolation algorithm will, in effect, give more weight to northern and southern neighbors (and less weight to eastern and western neighbors) when it estimates the value for each output grid cell. This bias is much greater at cells in Michigan than it is at cells in Mississippi. Consequently, the spatial pattern you think you "see" in your display might reflect the unwanted distortion pattern as much as it reflects the election geography. Project your data properly - it'll be worth the effort.

Well, "duh."

(h/t: TPM)