Spatial characteristics of exurban settlement pattern in the United States

Despite pervasive exurban development in the United States (US) over the last several decades, a lack of relatively precise data has hindered basic research, including classification of the types of emerging exurban settlement patterns. But because exurbia transcends the traditional dichotomy of urban versus rural and metropolitan versus nonmetropolitan, standard census data are of limited value in analyzing these regions. To address this gap, we made use of a spatially explicit population database to indentify and examine the configuration of exurban settlement. We developed a multidimensional spatial patch index, which captures the variation exurban settlement across the landscape, along the lines of shape, size and contiguity typology of exurban patches. This index reveals substantial heterogeneity in fine-scale pattern not reflected by aggregate measures of exurban settlement density. Using this index, we then explored to what extent metropolitan characteristics commonly believed to influence urban decentralization also are associated with the configuration of decentralization. We find that while large, contiguous clumps of exurban settlement are correlated with these metropolitan characteristics, other exurban pattern types (such as isolated or linear patches) are not. Therefore, it appears that the factors that contribute to more urban decentralization may also lead to greater contiguity and concentration of exurban settlement. Additionally, we find that the processes that lead to isolated and dispersed exurban settlement may be different from those that foster contiguous, concentrated exurban settlement.