Visualizing Health and Healthcare Data

Chapter SevenMaps

Using Maps to Gain Insights

Geographic Maps

Geographic maps are abstractions that allow features in the real world to be represented digitally or on paper. They rely on the arrangement of information, and on spatial relationships between elements of that information, to convey meaning.

Overlaying one or more data elements on a geographic map allows better presentation and a more precise understanding of the differences or similarities between geographic areas. These features and capacities make geographic data maps a powerful and intuitive way to show geospatial data.

Four useful types of maps can help visualize health and healthcare data: choropleth, hex-tile, symbol/dot-density, and proportional dot-density maps.

Choropleth Maps

A choropleth (from the Greek words for “area/region" and "multitude") is a thematic map in which areas are shaded or patterned in proportion to the measure being displayed. They are an easy way to visualize how a measurement varies across a geographic area, or to show the level of variability within a region. Color saturation corresponds to a measure's value, typically with more saturated color representing higher values and less saturated color representing lower values.

Choropleth maps were a complete game-changer two decades ago when they were used by Dr. Jack Wennberg, founder of the Dartmouth Atlas Project, to show glaring variations in medical resources distribution and use in the United States. Their impact has been profound, ...