Index Value Plot

The easiest way to understand an index value plot is to first best understand what an index is.  In index is a statistical indicator or number derived from a formula, which is used to characterize a set of data.  An index value plot is a type of visualization map that is plotted on a line graph.  What an index value plot allows one to do is look at variations over a situation.   The above index value plot shows the rainfall recorded in inches in Oregon from 1999-2006.

The map URL is: http://mylifeasihaveknownit.blogspot.com/2008_12_01_archive.html