What do the social networks look like in your city or country? Dave Troy (TED Talk: Social maps that reveal a city’s intersections — and separations) crunches data to see places not as neighborhoods, but as relationships between people. With his PeopleMaps project, he groups people by whom they follow and talk to on Twitter, then works with local collaborators to analyze what those people talk about most. The result? Fascinating non-geographic maps of a region’s interests and communities.

RIO DE JANEIRO: Rio de Janeiro appears as a big, complicated city. While there is a divide between what you might call rich and poorer communities, there is a lot of mixing in the middle. There are also many different communities of interest around specific types of music. Over time, we should be able to identify even more communities and see where they’re bridging and not bridging. But in general, Rio seems like it is very diverse and mixed, especially among young people.

SAUDI ARABIA: As Saudi Arabia cracks down on press freedoms, people have been turning to social media to communicate and organize. This is an early map of a complicated place; we can see that the communities are arranged on an axis from liberal to conservative, with football in the middle. We can also see a subnetwork for sex and gay porn, which we also see in Istanbul, another place with Internet censorship.

SAN FRANCISCO: It’s been well-reported that there are tensions in San Francisco surrounding the influx of venture capital investment and technology companies. This map shows this divide. There’s even a community that’s so distinct that it’s clearly identifiable as Twitter employees — understandable, since this is showing Twitter relationships. This map also reminds us that these maps are not geographical — they are maps of communities of relationships, and are not geographically correlated in any way, despite the similarity to the shape of the San Francisco peninsula.

MUNICH: Twitter usage in Munich is roughly 10-12 times less than that observed in Barcelona or Istanbul. This may be because of German attitudes around privacy and sharing, or it may be due to a relatively high standard of living, a free press, and the lack of a large minority community that feels a need to network among itself. Most of the users seem to be promoting products, services, media, events — and FC Bayern.

ISTANBUL: Istanbul has a large population of young male “poets” — the largest cohort I identified in the city. They are talking about getting girls and music and being a guy right now, but soon they’re going to start to want real jobs and begin to vote. The big question for Turkey is where those young men will turn their energy — to democratic values or fundamentalist viewpoints. Also note the clear presence of a “gay porn” subnetwork, which is something we’ve observed in other places where Internet content is censored. We also noticed a subnetwork of “trolls,” who appear to exist primarily to repeat others’ content. This may be part of an astroturfing campaign to amplify certain political messages.

BARCELONA: Barcelona presents as a colorful beachball, and it’s perhaps the most “well-rounded” city we’ve plotted. Catalunyan independence is a hot topic, of course, as is the famed FCB football team. Barcelona’s communities wrap neatly around what appears to be a varied array of mainstream media outlets. Bookworms and library fans are even clearly identifiable (opposite the FCB fans, sorry to say). Twitter usage is quite high in Barcelona, perhaps attributable to the recent combination of economic and political changes.

BALTIMORE: The Baltimore map shows a pattern of rather extreme racial segregation. The map is for the most part divided: on the left, primarily African Americans and other non-whites, and on the right, mostly whites. It mirrors the divided city that I observe every day as a resident. We should try to bridge these divides better.