Data shown on maps

Some data is easier to understand when it is shown on a map. This is especially true of spatial data, where the spread of the information is important.

Choropleth Maps

Choropleth maps show interval data (data that is linked, rather than data from different categories) as colours. They are shaded in using one colour, where the darker shades represent high numbers and the lighter shades represent low numbers. A choropleth map needs a key to explain what the different shades mean. Population density can be shown using a choropleth map.

Chloropleth map showing global population density. Degrees of density are categorised by colour and explained in a key below the map.World population density

When describing chloropleth maps, you should include:

  • The most common and least common.
  • A comparison of different areas linked to the information in the key
  • Any patterns shown on the map.
  • Any anomalies i.e. things that you would not expect to see.


Describe, in detail, world population density

The population density of the world is unevenly distributed. The most densely populated areas are cities like London, New York and Tokyo. The least populated areas are extreme environments like the Amazon rainforest, Sahara desert and arctic Canada. Places that are densely populated include NE USA, coastal Brazil and east China. Places which are moderately populated include central Africa, New Zealand and Mexico. Places that are sparsely populated include Antarctica, Greenland and central Australia. A small part of the Sahara Desert in Northern Africa is densely populated.