Throughout my education, cartograms have been one of my favorite forms of cartographic visualization. Cartograms work on the principle of deforming data based upon an external factor. In the first example, the boroughs of London have been altered based upon the mean equivalent income. As can be seen the City of London region has been significantly increased whereas Havering has been reduced.
The above example was created using Quantum GIS and the ‘Cartogram Creator’ plugin. The data used are the London Stat pack provided by the London DataStore and joined to a London boroughs shapefile from the same store. The cartogram projection used in the example is the Dougenik, Chrisman and Niemeyer cartogram. The cartogram is presented alongside a correctly presented map of London to help with comparison. A purple colour ramp due to the associated of the colour purple with wealth.
If you have any comments or suggestions of good cartograms or other maps please post them into the comment box.