Choropleth Mapping
Reading: Chapters 4 & 14

Example choropleth maps:
CDC-NCHS examples :  heart disease  (detail), cancer

Type of phenomena mapped: abrupt, continuous
Basics of classification

Classification types

Constant intervals:

• equal interval
• mean-standard deviation

• irregular: quantiles
• systematic: arithmetic,geometric

• natural breaks by eye
• maximum breaks
• Jenks optimization ('natural breaks' in ArcMap)

U.S. example maps
Stroke, white female, mortality rates

Mapped by HSA - Hospital Service Areas (aggregates of counties)

Example histograms for stroke maps (sideways)

Quantile map:

Boxplot map:

Example ArcMap Classification window:

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