Standardized Choropleth Map

http://www.portal.gsi.gov.in/pls/portal/url/page/GSI_STATIC/GSI_STAT_SEARCH_MAP_INFO

A standardized choropleth map used data that has been standardized; that it to say that the data is standard to a particular industry; everyone uses the same data. For example, standardized population data of the U.S. would come from the U.S. Census Bureau. The choropleth above uses standardized data to show geological information or rock classifications in India.

Univariate Choropleth Map

http://www.gismonitor.com/news/newsletter/archive/archives.php?issue=20060622&style=web&length=full

A univariate choropleth map only demonstrates one variable. The map above depicts unemployment in Portland, Oregon in the year 2000. Shading from light to dark demonstrates the degree to unemployment existed at that time. The author used four categories of shading to display this variable.

Bivariate Choropleth Map

http://www.geocities.com/stevejford/new_page_2.htm

A bivariate choropleth depicts two variables. The map of Africa above demonstrates life expectancy in years as compared with GNP per capita in U.S. dollars. The pie chart below the bivariate choropleth is a third variable that shows land use.

Unclassed Choropleth Map

http://www.math.yorku.ca/SCS/Gallery/milestone/sec5.html

Unclassed choropleth maps use continuous tone shading to depict values. There is no data chart, key, or schedule that goes with this type of map, thus we call it unclassed. The map above should be familiar to those who study maps; it is the first unclassed choropleth map; it represents the “distribution and intensity of illiteracy in France” and it was created by Pierre Charles François Dupin in 1826.

Classed Choropleth Map

http://www.ilstu.edu/~jrcarter/Geo204/Choro/Tom/
Choropleth maps are another version of a thematic map. The above choropleth is classed and represents the percentage of Hispanic or Latino people by county in Florida. The classes of a choropleth map are the variables that the map is depicting. Typically there are five classification methods used in a Classed Choropleth Map. They are natural breaks, nested means, equal interval classes, quartiles, and skewed distributions. The data for this map is compiled using the natural breaks method.

Continuously Variable Proportional Circle Map

//www.math.yorku.ca/SCS/Gallery/bright-ideas.html

Proportional circle are a form of cartogram. The image above shows how the continuously varying circles can represent the values of the cartogram. The image on the right has also been referred to as a circle-cartogram. This type of cartography depicts the point values as circles that may have an infinite number of sizes, to the extent that they can be shown and viewed practically.

Range Graded Proportional Circle Map

http://mapmaker.rutgers.edu/355/links.html
The image above is a variation of a dot distribution map. Circles of varying sizes are used instead of dots. The circles indicate point data and the size of the circles indicate the degree of the variable that is measured. In this case the variables are range graded; that is to say that they represent predetermined sizes. For example, the rural populations are noted as either 500 or 1000 – 2500. This map demonstrates the population of the areas surrounding Detroit and Chicago.