URBAN CLUSTERS AS GROWTH FOCI

Urban clusters are geographic concentrations of urban places, some of which may include major cities. Unlike agglomerations, whose geographic boundaries are clearly delineated, urban clusters have variable boundaries, with each urban settlement being part of its own cluster of populated places, located within its commuting range. As our study indicates, the effect of clustering on urban growth is not uniform: it appears to be positive in low density clusters, and negative in densely populated ones. In particular, outside densely populated areas, towns surrounded by other localities tend to evince higher rates of population growth than their lone counterparts.