Classed Choropleth Maps

http://courses.washington.edu/info424/Labs/ChoroplethMap.html

A Classed Choropleth Map differs from an unclassed map in that intervals are created to display the data in a more simple manner. The number of intervals created can vary. Another thing that can vary is the way data is divided up into intervals. The classed choropleth map above shows a one-year forecast change in jobs for 2010 verse 2009. The data is divided into six intervals with a different color for each. 

Nominal Area Choropleth Map

http://geoportal.icimod.org/TrainingandEducation/GISforBeginners/p1ch8/

Nominal Area Choropleth Maps are used to display nominal data. These types of maps use different colors or patterns to distinguish between certain areas or regions. Usually there is no ordering (or ranking) of the data. But this map strays away from that rule. This nominal area choropleth map should which regions have access to safe drinking water. 

Bivariate Choropleth Maps

http://www.directionsmag.com/articles/sports-illustrated-from-swimsuits-to-maps-the-making-of-the-si-sports-atlas/123556

This map is called a Bivariate Choropleth map of the United States which shows where many of our Olympic Athletes come from. A Bivariate Choropleth map uses two variables and different shading to show concentration of those variables.  

Range Graded Proportional Circle Map

http://www.neiu.edu/~ejhowens/377/examples.htm

Range Graded Proportional Circle Maps show a selected range of values that correspond to the charting of the number of occurrences on the map. This map shows the populations of Filipino's in the Southeastern United States in the Year 2000. I like this maps because they are easy to interpret and fun to look at. 

Unclassed Choropleth Map

http://www.math.yorku.ca/SCS/Gallery/milestone/thumb5/popup/bssn1_popup1-19.htm

Unclassed Choropleth Maps assign shadings proportional to the amount of data rather by a key with percentages or numbers of occurrences. This maps will usually just show the area with no other help from keys like we normally see on maps. This map here shows the reading literacy rates in France during 1826. 

Univariate Choropleth Map

http://people.cas.sc.edu/hardistf/research.htm

Univariate Choropleth Maps only show one variable or one single attribute. This map shows the occurrence of a single variable. The darker areas show high concentration. These maps are useful when studying only one factor. 

Unstandardized Choropleth Map

http://www.uwec.edu/webprojects/geog367/northwoods/silent_sports.html

Unstandardized Choropleth Maps are usually used to show distributions of a variables. It lacks standardization and is not an average. This is a map of number of canoe shops by county around the Great Lakes. The darker colored shapes are more concentrated than the lighter ones.