https://www.tableau.com/en-gb/visualization/what-is-cloropleth-isopleth-area-maps
A Guide To Choropleths, Isopleths, and Area Maps | Tableau
Learn more about the differences between choropleths and isopleths, two types of area maps, as well as how to read and use them both.
a guide toarea mapsisoplethstableau
https://www.usgs.gov/data/depth-water-area-polygons-isopleths-showing-mean-annual-runoff-1912-1963-and-water-level
Depth-to-water area polygons, isopleths showing mean annual runoff, 1912-1963, and water-level...
This USGS data release represents the 1:500,000-scale geospatial data for the following publication: Eakin, T.E., and Lamke, R.D., 1966, Hydrologic...