David B. Sparks:

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.

The isarithmic depiction does an excellent job of highlighting several broad patterns in modern U.S. political history. First, it does a good job of depicting local "peaks" and "valleys" of partisan support clustered around urban areas. Comparison of these maps across time also underscores well-known political trends, but offers more resolution than state-level choropleths and greater clarity than county-level choropleths.

Interpolating support between elections, I have generated a video in which these maps shift smoothly from one election year to the next. The result is the story of 20th century presidential politics on a grand scale, condensed into a little over a minute of data visualization.

From the archive:

The "Gospel Temperance Railroad Map" is an example of an allegorical map.

The blue may be small in area, but they are large in terms of numbers of people, which is what matters in an election. We can correct for this by making use of a cartogram, a map in which the sizes of states have been rescaled according to their population.

On Stefanie Posavec:

Posavec's approach to the text is not unlike that of a surveyor. And similarly, the act is near reverential in its approach and the results are stunning graphical displays of the nature of the subject. The literary organism, rhythm textures and sentence drawings are truly gorgeous pieces. It's not often that I am so thoroughly impressed by the depth of an artist's work, but somehow, for me, these pieces do it all.

On religion:

There are few sources of comprehensive data on church membership and religious affiliation for the United States. Perhaps the leading organization to address this gap is the Glenmary Research Center, which publishes Religious Congregations and Membership in the United States, 2000. The following series of county-level choropleth maps, which reveals the distribution of the larger and more regionally concentrated church bodies, draws on this resource.