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. 2010 Nov 10;5(11):e13541. doi: 10.1371/journal.pone.0013541

Figure 4. Families of kindred cities.

Figure 4

The cross-correlation between SAMI time-series gives a measure of similarity, which can be used to group cities into clusters with similar characteristics; A) sorted correlation matrix (heatmap) for personal income in US MSAs with population over 1 million. Red (blue) denotes greatest (dis)similarity; B)Dendrogram showing detailed urban taxonomy of USMAs according to personal income. This clearly manifests clustering among cities with similar time trajectories. Here we used a decorrelation measure Inline graphic as distance between any two cities, where Inline graphic is the cross-correlation of Figure 4A. When the decorrelation Inline graphic, Inline graphic, indicating no correlation(dashed line), revealing five families of kindred cities. See Figures S2, S3, S4, S5, S6, and S7 for other quantities.