Unclassed Choropleth Map

http://www.agroatlas.ru/en/content/climatic_maps/S_Temperature/S_Temperature_01/

http://quizlet.com/7774717/the-choropleth-mapping-method-flash-cards/

In an unclassed choropleth map, the maps areas are colored depending on their unique relation to the single variable that has been mapped. As a result, these maps tend to take on a gradational color scheme and are much more vague.