Skip to content →

The History Of The Two-Party Presidential Vote Mapped

Cloropleths vs Isarithmic: Voting within or without boundaries

There have been two major ways to understand populations and their territorial distribution. In one kind, typified by choropleth maps, the density or degree of a feature is mapped in pre-given political units.*

Cloropleths Map of the Presidential Vote 2008
Cloropleths Map (c) David B. Sparks

As second kind of map, known as isarithmic mapping (…), shows change varying continiously over space.*

isarithmic map of the presidential vote 2008
Isarithmic mapping (c) David B. Sparks

Where chloropleths maps produce a sense of populations as contained within boundaries, isarithmic mapping emphasizes continual variation and gradual change without clear differentiations.*

References

Published in Blog Books Visualization