The other day I read about a new study of gang territory and violence in Los Angeles, that uses a formula developed to "model the population dynamics of species competing for common resources," everything from lions to bees to chimps to moose, to study where violence occurs in that city (which has similar gang problems as Chicago). The conclusion is pretty obvious, I'll grant: "[T]he research demonstrates that the most dangerous place to be in a neighborhood packed with gangs is not deep within the territory of a specific gang, as one might suppose, but on the border between two rival gangs. In fact, the highest concentration of conflict occurs within less than two blocks of gang boundaries, the researchers discovered."

One might suppose, but I doubt most people would. It's a case of science stating the obvious, but the methodology is pretty interesting:

Using the Lotka-Volterra formula, Brantingham's team drew boundaries between the known gangs. Unlike law enforcement's maps, the resulting effort did not produce gang boundaries that neatly followed streets. Instead, the boundaries ran through the yards of homes and businesses and through alleyways. When the boundaries did land on streets, they were as likely to crisscross them as follow them.

With the caveat that gang boundaries don't necessarily follow streets, and that any attempt to map gang territory is an attempt to nail down something fluid (especially given the factionalization of Chicago gangs), I mapped last night's shootings—six in all, with 19 people shot—on the map that ran with our "Gangs and Politicians in Chicago" story. Obviously I had to eyeball it a bit, but they're all accurate within a block or two. And sure enough, they tend to line up with gang borderlands.

The shooting indicated by the maroon marker is the one in which eight people were shot:

The shooting likely stemmed from a conflict between two factions of a gang that uses 75th Street as a dividing line, according to police, who said some of the wounded people were not cooperating.

The victims are 28, 20, 19, 16, 16, 15, 14, and 14 years of age. The map (and the 2012 gang book) indicate the shooting happened on the dividing line between the territory of the Gangster Disciples and the Black P Stones. Of the six shootings, only one was well within gang territory, on the 2900 block of West 39th in Brighton Park (the pink marker).