After the last post, which looked at housing values across New York City, I thought it would be interesting to take a more granular look at housing values across the U.S.
To create the map below, I took the total residential property value for every county in the U.S. (the contiguous 48 states), and substituted those values for each county's land area.
Aside from the Northeast, property value in the U.S. is concentrated in a relatively small number of areas. In the animation below, notice what a small portion of the U.S. land area is actually covered by the red counties.
This type of map, in which each area is substituted by some other mapping variable, is called a cartogram. They are not used all that often because there can be a fair amount of manual work involved in making the areas accurately sized while maintaining the basic shape.