bivariate choropleth maps

http://mcs08c.blogspot.com/2010_07_01_archive.htmlhttp://mcs08c.blogspot.com/2010_07_01_archive.html

nominal area choropleth map

http://my.ilstu.edu/~jrcarter/Geo204/Choro/Tom/

classed choropleth maps

http://gis3015erickson.blogspot.com/2010/04/classed-choropleth-map.html

unclassed choropleth maps

http://sarahpopesblog.blogspot.com/2011/04/unclassed-choropleth-map.html

continuously variable proportional circle map

http://sarahpopesblog.blogspot.com/2011/04/continuously-variable-proportional.html

range graded proportional circle maps

http://www.johnkeim.blogspot.com/

bilateral graph

http://dominiquegrant.blogspot.com/2009/04/bilateral-graph.html