Isopleth

source: http://www.stonelions.com/Jacksonville.htm

Isopleth maps are the generalized contour line maps used to display variables continuously over a geographic area. For instance, population density can be showed using contour lines which gives the reader an idea of a density epicenter. Above is an air dispersion model of toxic chemical emissions from waste incinerators in Jacksonville, Fl. A lot of interesting information can be ascertained from this type of map for instance where the highest concentrations of toxic chemicals are and where they traveled (based on wind).