Spatial Thinking in Planning Practice: An Introduction to GIS

35 Figure 4.13. County population change rates divided into !ve equal interval categories. Source: Department of Geography, "e Pennsylvania State University. In the second graph, the data range of each class is equivalent (8.5 percentage points). Consequently, the number of counties in each equal interval class varies. Figure 4.14. "e !ve quantile classes mapped. Source: Department of Geography, "e Pennsylvania State Uni- versity. Figure 4.15. "e !ve equal interval classes mapped. Department of Geography, "e Pennsylvania State Univer- sity. Chapter 4: Mapping People with Census Data