From the web site......
The MapThis map is an American snapshot; it provides an accessible visualization of geographic distribution, population density, and racial diversity of the American people in every neighborhood in the entire country. The map displays 308,745,538 dots, one for each person residing in the United States at the location they were counted during the 2010 Census. Each dot is color-coded by the individual's race and ethnicity. The map is presented in both black and white and full color versions. In the color version, each dot is color-coded by race.
All of the data displayed on the map are from the U.S. Census Bureau's 2010 Summary File 1 dataset made publicly available through the National Historical Geographic Information System. The data is based on the "census block," the smallest area of geography for which data is collected (roughly equivalent to a city block in an urban area).
The map was created by Dustin Cable, a demographic researcher at the University of Virginia's Weldon Cooper Center for Public Service. Brandon Martin-Anderson from the MIT Media Lab deserves credit for the original inspiration for the project. This map builds on his work by adding the Census Bureau's racial data, and by correcting for mapping errors.
The DotsEach of the 308 million dots are smaller than a pixel on your computer screen at most zoom levels. Therefore, the "smudges" you see at the national and regional levels are actually aggregations of many individual dots. The dots themselves are only resolvable at the city and neighborhood zoom levels.
Each dot on the map is also color-coded by race and ethnicity. Whites are coded as blue; African-Americans, green; Asians, red; Hispanics, orange; and all other racial categories are coded as brown.
Shades of Purple, Teal, and Other ColorsSince dots are smaller than one pixel at most zoom levels, colors are assigned to a pixel depending on the number of colored dots within that pixel. For example, if a pixel contains a number of White (blue dots) and Asian (red dots) residents, the pixel will be colored a particular shade of purple according to the proportion of each within that pixel.
Different shades of purple, teal, and other colors can therefore be a measure of racial integration in a particular area. However, a place that may seem racially integrated at wider zoom levels may obscure racial segregation at the city or neighborhood level.
|Sandy Springs and Dunwoody, and north Brookhaven|
|Metro Atlanta Race Dot Map, north/south racial divide. Buford Hwy corridor also visible.|