Isopleths

http://www.wbdg.org/resources/env_iaq.php


Isopleth maps are a type of contour map, isopleths must be taken over an area, not at a specific point. The above isopleth map shows the germination of mold and it's relation to % humidity and temperature. Isopleth maps can also be compared to choropleth map, because of how they both require a ratio of area and magnitude.