As the story goes, Eric Fisher was so fascinated by cartographer Bill Rankin’s race map of Chicago, that he created one for each of the top 40 U.S. cities using 2000 census data. According to Gawker, Rankin used the same method as Rankin; “one dot equals 25 people. The dots are then color-coded based on race: White is pink; Black is blue; Hispanic is orange, and Asian is green.”
While some of the denser urban cities, like New York City, reveal more dramatic patterns, Atlanta above is also quite interesting once you get your bearings. The actual Flickr image might be of assistance, since a few people have already identified areas of the city (including Decatur) for you.
Buford Highway is probably the most obvious feature on the map above, with the strip of orange and green extending up Buford Highway and I-85 in the upper right corner of the map. Decatur sits below that, along the red/blue divide of the CSX rail line. White areas of the maps are often airports and train yards. Hartsfield is quite noticeable in the lower half of the map.
It would certainly be interesting to see this same map again with 2010 data once it becomes available!