What is the difference between an isopleth map and a choropleth map?
Both are map techniques to geographical variations. However, choropleth map colour in each REGION on the map according to a key whereas an isopleths map draws lines (like contour lines) to show the gradient of changes. Isopleth (or isoline) maps include isobars, isotherms, isohyets, contours as well as isoprices. By definition, an isoline joins all the places with the same value.
