Unstandardized Choropleth Map

http://cartography.uni-muenster.de/en/map-types

An unstandardized choropleth map is similar to other types of choropleth maps except that the class key used in unstandardized choropleth map uses assymetrically specific numbers that fit with the map area represented. The unstandardized choropleth map allows for much more accuracy and pragmatism as well as allows the cartographer more freedom to narrow the ranges to fit their purpose. The image shown above is an example of an unstandardized choropleth map where you can witness the cartographer using specific ranges unique to Sao Paulo's total population and population density in 1991.

Standardized Choropleth Map

http://www.statcan.gc.ca/pub/92f0138m/2008003/figures/5200001-eng.htm

A standardized choropleth map utilizes state and country boundaries to delineate and separate areas. County areas then have their own saturated color separate from the country. All countries can use standardized choropleth maps because all countries have a type of governmental subdivision similar to counties that have their own representative data unique to themselves. Counties next to each other may have the same color, but it doesn't mean they have the same data. Standardized choropleth maps are simple to read and can help make governmental decisions as well as educate the public about their own county and country statistics overall. The image above is an example of a standardized choropleth map that utilizes county and country boundaries to distinguish data for Canada separated from the United States.  

Univariate Choropleth Map

http://water.usgs.gov/edu/wudo.html

A univariate choropleth map shows statistical data aggregated over predefined regions with coloring or shading of these regions. Univariate choropleth maps assume a relatively even distribution of the measured phenomenon within each region. Depending on the map data of the univariate choropleth map there are differences in hue to indicate qualitative differences while differences in saturation or lightness are used to indicate quantitative differences. The image shown above is of a univariate choropleth map showing water usage across the United States where extensive use of water was shown by blue color saturation.

Bivariate Choropleth Map

http://www.geo.unizh.ch/~annal/Choropleth%20maps.html

A bivariate choropleth map displays two variables on a single map by combining two different sets of graphic symbols or colors simultaneously. The main objective of a bivariate choropleth map is to find a simple method for accurately and graphically illustrating the relationship between two spatially distributed variables. Bivariate choropleth maps have potential to reveal relationships between variables more effectively than a side-by-side comparison of the univariate maps. Bivariate mapping is a recent graphical method which is intended to convey the spatial distribution of two variables and the geographical concentration of their relationship. The image shown above is an example of a bivariate choropleth map that combines to show what percentage of the population is under eighteen as well as those that live in rural areas in Poland.

Unclassed Choropleth Map

(middle of page)

http://www.mapresso.com/example/bfs/screenshots.html

An unclassed choropleth map is useful to show data for a country overall without getting into specific counties or states. An unclassed choropleth map does not deal with averaging out data to a certain amount of classes so it uses a continuous tone scheme to represent data in a blotchy amorphous way. Unclassed choropleth maps are not restricted with boundaries so that there is an accurate yet unorganized general view of how data is represented for a region. The image shown above is an example of an unclassed choropleth map where the continuous tone scheme represents concentrations of women who are 50-64 years old have more than three children over the country as a whole.

Classed Choropleth Map

http://archive.eps.mq.edu.au/courses/GEOS219/choropleth.htm

A classed choropleth map uses shading and other techniques to represent data in groups or classes. A classed choropleth map usually uses a mono-color light to dark technique where the lighter shade represents less of the target data and darker shades of the color represent more of the targeted data in the specific area. Classed choropleth maps are usually shown to represent survey data and census information.The image shown above is a classed choropleth map that has six classes and classifies the counties in Australia by deaths per one thousand live births. 

Range Graded Proportional Circle Map

(bottom of page)

http://www.geog.ucsb.edu/~jeff/gis/proportional_symbols.html

A range graded proportional circle map is a type of symbol map that utilizes a circle size within a certain range of data. Point data is mapped with a circle instead of a dot, and there are a finite or set number of sizes used for the circles. A range graded proportional circle map is used when the the map makers want to show an average to fit with a set number of circles. The map shown above is an example of a range graded proportional circle map of internet users in 2004 in western Europe.