Choropleth Maps
Choropleth Map - a thematic map in which areas are shaded or patterned in proportion to the measurement of the statistical variable being displayed on the map, such as populaiton density.
The choropleth map provides an easy way to visualise how a measurement varies across a geographic area or it shows the level of variability within a region.
Examples of Choropleth maps:
Image Source: http://www.mtholyoke.edu/courses/rschwart/hist256/student_work/Fuchslab2.htm
Image Source: http://richmondtransits.blogspot.com/2008_09_01_archive.html
Choropleth maps will use graduated colour ramps, this gives an immediate visual impression of the pattern without seeing the key; examples of colour ramps are:
