Isopleth Maps

Isopleth maps are a type of thematic map used to display and model observations of phenomena with a continuous distribution by representing the values as a third-dimensional surface draped over the area. This common mapping technique is appropriate for diverse topics. Similar terms, mapping techniques, value interpretation, and specific isopleths, especially contours, are discussed.

Broadly called isoline maps, a distinction is sometimes made between isometric and isoplethic mapping, wherein isometric maps display real values such as rainfall amounts and isoplethic maps display calculated values such as population density. The terms isarithm and isogram are generally synonymous. Iso means “equal,” and pleth refers to “quantity.”

If something can be measured or generalized at any location, such as air temperature, then potentially, isopleth mapping can be used to show ...