Several years back, the sociologist Kieran Healy made note of the fact that when it comes to mapping pretty much any social phenomenon across the United States, there’s a good chance that the resulting spatial pattern will be strongly correlated with one of two other variables. First is population density, with the densest counties scattered across the US in the heart of large urban centers. Or, second, the share of Black population, which tends to be tightly clustered across the South in what is often referred to as, unsurprisingly, the Black Belt. Healy called the resulting maps of these two variables America’s ur-choropleths.

To begin this indefinite experiment in mapping all things Atlanta, I thought it worth starting with what I already know to be Atlanta’s ur-choropleth; the one variable whose spatial pattern will be mimicked by so many other spatial patterns, regardless of how tangential the two may seem. Much like the country as a whole, so many maps of Atlanta could easily be confused for maps of the city’s Black population.

Using data at the scale of the Census tract, this map shows all those parts of Atlanta that are majority Black, and all of those that aren’t. But in Atlanta, a city that only recently shifted from being majority Black to plurality Black for the first time in 50 years, anything that’s not Black is pretty much automatically assumed to mean white. And that’s because for pretty much the duration of Atlanta’s existence, it’s been a city marked by the perpetual back and forth between Black and white.

Long story short, most variables mapped across the city of Atlanta are going to mimic this spatial pattern, with one cluster of values for predominantly Black neighborhoods and another for predominantly white, with the dividing line running diagonally from the city’s northwest to southeast. While there are the occasional anomalies, this pattern holds for everything from household income, to poverty, to educational attainment, and countless other variables one might typically map to help make sense of the big picture for a given city. That this is true only further engrains the division between Black Atlanta and white Atlanta into the spatial imaginaries of all the city’s residents.

It even makes it into the city’s master planning document meant to chart the future of changes to the built environment. Though framed through the ostensibly non-racial lens of growth, this map of the ‘growth line’ from page 130 the Atlanta City Design reproduces almost exactly Atlanta’s ur-choropleth shown above. Even though the line turns a bit more horizontal as it moves into the city’s east side, the association between “Strong/Stable Growth” north of the line in the city’s white neighborhoods and areas of “Low/No Growth; Decline” south of the line in the Black neighborhoods to the south should be entirely intuitive to any Atlantan.

But given that we don’t always share an understanding of what counts as Atlanta, it’s important that we look beyond the city’s jurisdictional borders to the more nebulous place we call Atlanta to anyone who doesn’t live here and know the difference. So extrapolating out our Black/white binary to the metro area’s five core counties, the pattern now looks something like this…

Rather than just a diagonal line cutting across the city running from the northwest to the southeast, the pattern now looks like wedge centered on Moreland Avenue running to the northwest through Fulton and Cobb, and to the northeast through DeKalb and Gwinnett. This too is Atlanta’s ur-choropleth if you think of the place as being more than just what falls within the formal jurisdiction of the city.

The problem, of course, is that despite the longstanding mental image of an Atlanta divided between Black and white, it’s not quite that simple anymore. While it once would have been entirely fair to assume that an Atlanta neighborhood with a 60% Black population would have a 40% white population, this has been complicated by the fact that Atlanta is an increasingly multi-racial metropolis, with a significant and ever-growing number of people who don’t fit the Black/white binary the city is used to thinking about. We even boast the most diverse square mile in the county, the Ellis Island of the South.

In fact, a lot of those places labeled as ‘white’ on the maps above aren’t majority white at all. Some aren’t even plurality white. They are instead metro Atlanta’s pockets of predominantly Latinx and Asian neighborhoods stretching out into the suburbs along Buford Highway to the northeast, along with some other scattered areas across the northern part of the metro area. There are even a few places previously labeled ‘white’ that are in fact plurality (but not majority) Black.

Given those simplifications in the previous iterations, perhaps it’s really this map that’s Atlanta’s ur-choropleth? Or maybe Atlanta has more than one ur-choropleth after all? Either way, you’re sure to be seeing a lot more of these patterns in the future.