Comprehensive framework for visualizing and analyzing spatio-temporal dynamics of racial diversity in the entire United States

Abstract

The United States is increasingly becoming a multi-racial society. To understand multiple consequences of this overall trend to our neighborhoods we need a methodology capable of spatio-temporal analysis of racial diversity at the local level but also across the entire U.S. Furthermore, such methodology should be accessible to stakeholders ranging from analysts to decision makers. In this paper we present a comprehensive framework for visualizing and analyzing diversity data that fulfills such requirements. The first component of our framework is a U.S.-wide, multi-year database of race sub-population grids which is freely available for download. These 30 m resolution grids have being developed using dasymetric modeling and are available for 1990-2000-2010. We summarize numerous advantages of gridded population data over commonly used Census tract-aggregated data. Using these grids frees analysts from constructing their own and allows them to focus on diversity analysis. The second component of our framework is a set of U.S.-wide, multi-year diversity maps at 30 m resolution. A diversity map is our product that classifies the gridded population into 39 communities based on their degrees of diversity, dominant race, and population density. It provides spatial information on diversity in a single, easy-to-understand map that can be utilized by analysts and end users alike. Maps based on subsequent Censuses provide information about spatio-temporal dynamics of diversity. Diversity maps are accessible through the GeoWeb application SocScape (http://sil.uc.edu/webapps/socscape_usa/) for an immediate online exploration. The third component of our framework is a proposal to quantitatively analyze diversity maps using a set of landscape metrics. Because of its form, a grid-based diversity map could be thought of as a diversity "landscape" and analyzed quantitatively using landscape metrics. We give a brief summary of most pertinent metrics and demonstrate how they can be applied to diversity maps.

Fig 1. Maps showing distribution of the Hispanic population in central Chicago according to Census tracts (panel A for 2000 and panel B for 2010) and according to high resolution grids (panel D for 2000 and panel E for 2010).

Census tracts boundaries are overlaid on grid-based maps for reference. Extent of the ZIP Code is shown in blue. Inset in panel E is to show the high (30m) resolution of the grid. Racial diversity grid-based map (D) shows spatial extents of two communities, Blacks-dominated (green color) and Hispanic-dominated (violet color).

Fig 2. Classification of population into 39 different communities based on degree of diversity, dominant race, and population density.

Colors serve as a legend to the diversity maps (see Fig 3), numbers are numerical labels as encoded in diversity data downloadable from SocScape.)

Fig 3. Racial diversity maps of the Chicago area for 1990, 2000, and 2010.

The upper row shows maps for the greater Chicago area and the lower row shows maps for the central Chicago area indicated by a red rectangle on the broader extent map for 1990. Major roads are overlaid for geographical reference. For the legend of community categories see Fig 2, the white color indicates uninhabited areas.