3 Thematic Maps

Thematic Maps  

Thematic maps are used to look at a particular feature or variable. For example, one might look at the population size, a particular ethnicity, or poverty level, etc. This data would then be represented on a thematic map.

Choropleth Map

A choropleth map shows levels of a particular variable using a different color. Here is an example:

Source:  www.stockmapagency.com

 This map shows the population density of Ireland using different shades of red. By looking at this map, we can see that the city of Dublin on the East Coast is more populated than the city of Dingle in the South.

Proportional Symbol Map

A proportional symbol map uses a symbol to show frequency or intensity of a given variable.  By looking at the dots we can see the differences in each area. For example:

Source: homepages.rootsweb.ancestry.com

This map is looking at the ancestry of 3 Irish families. Each dot size represent the number of people in the family; the larger dots represent more people. Each of the three colors represents a different family.

Isoline Maps

Isoline maps use lines and connect points that have an equal value. A phenomenon would be examined by looking at each line. They would represent different occurrences of the same event. For example:

Source: www.scielo.cl 

In this map, the percentages of exotic plant species in Great Britain are shown. Looking at the numbers on the map, there is a larger percentage near Bristol where the numbers are much higher than those North, such as Edinburgh.