ISARITHMIC HISTORY OF THE TWO-PARTY VOTE (w cool video)

[mod mom]

ISARITHMIC HISTORY OF THE TWO-PARTY VOTE
Posted by d sparks on November 15, 2010 · 13 Comments

A few weeks ago, I shared a series of choropleth maps of U.S. presidential election returns, illustrating the relative support for Democratic, Republican, and third Party candidates since 1920. The granularity of these county level results led me to wonder whether it would be possible to develop an isarithmic map of presidential voting using the same data.

Isarithmic maps are essentially topographic or contour maps, wherein a third variable is represented in two dimensions by color, or by contour lines, indicating gradations. I had never seen such a map depicting political data — certainly not election returns, and thus sought to create them.

There is a trade-off between an isarithmic depiction versus a choroplethic depiction, in which a third variable is shown within discrete political boundaries. Namely, that though a politically-delineated presentation better facilitates the connection of the variable of interest to the level at which it was measured, the superimposition of geographically arbitrary political boundaries may cloud the existence of more general regional patterns.

Election-year maps can be seen in a slideshow here (and compared to the three-color choropleth maps here). The isarithmic depiction does an excellent job of highlighting several broad patterns in modern U.S. political history.

-snip

https://dsparks.wordpress.com/2010/11/15/isarithmic-history-of-the-two-party-vote/

Hat tip to TPM!

video:

http://www.youtube.com/watch?v=k4h62jRiUcc&fmt=22

[slackmaster]

1. Automatic rec for use of the words isarithmic and choroplethic in the same article

:kick:

[Laelth]

2. Nifty. Thanks for posting. n/t

-Laelth