Simple Cartogram of Breast Cancer Rates in
New York State

In contrast to standard maps which generally use colors to represent differences from area to area, cartograms use the exaggeration and distortion of areas to characterize this information. Although reducing distortion is usually the goal in cartography, deliberate exaggeration of shapes can also be a useful tool to produce memorable and quickly interpretable graphics.

In order to illustrate the difference between a cartogram and a standard chloropleth (color-based) map, breast cancer rates in New York State are represented here using both methods. On the right, different age-adjusted breast cancer rates in the New York State counties are represented by different shades of red. In the cartogram below, the county areas are exaggerated to represent different age-adjusted breast cancer rates. In order to see the difference, take particular note of Long Island -- an area with some of the highest breast cancer rates in New York State. The high rates are represented in the chloropleth as a dark red whereas the cartogram illustrates the high rates by increasing the areas of these counties proportionally compared with other counties. Naturally the county areas and shapes in the final cartogram image are no longer accurate but the image is memorable and quickly interpretable.

© 2008 ZevRoss Spatial Analysis