Isopleths

An isopleth map generalizes and simplifies data with a continuous distribution. It shows the data as a third dimension on a map. They are mostly used for mapping surface elevations, amounts of precipitation, atmospheric pressure, and other measurements that can be viewed statistically as a third dimension. This is an Isopleth map of Hydrogen Ion concentration in the United States in 2003. It shows that there is more Hydrogen Ion concentration in the western part of the United States, and the least amount in the North East.


http://nadp.sws.uiuc.edu/isopleths/maps2003/phfield.gif