It has long been observed that minorities are often concentrated in impoverished areas and lack access to resources such as jobs, educational opportunities, good-quality food, life services, and face other disadvantages. As such, racial and ethnic segregation is an important factor to consider when crafting public policy. A first step in many analyses of segregation is the production of single racial or ethnic group percentage maps that show geographic patterns where one group is predominant and the other is not. At lower levels of geography, such as census block groups or tracts, these percentage maps are less problematic because the size of the unit is small enough and can reveal a concentration of single racial or ethnic groups within a small area. When examining trends across the United States at the city and county level, however, the percentage mapping approach becomes disadvantageous for two primary reasons.