isopleth
/ˈaɪsəˌplɛθ/
noun
- A line on a map or diagram connecting points where a particular variable has the same value, such as temperature, rainfall, or population density.
- The climate map used isopleths to show regions with the same average annual rainfall.
- Demographers drew an isopleth connecting all towns with a population density of 500 people per square mile.
- On the temperature chart, each isopleth represented a constant degree of warmth across the country.