Every city has its neighborhoods, cliques and clubs, the hidden lines that join and divide people in the same town. What can we learn about cities by looking at what people share online? Starting with his own home town of Baltimore, Dave Troy has been visualizing what the tweets of city dwellers reveal about who lives there, who they talk to — and who they don’t.




  • settlement – a place, typically one which has previously been uninhabited, where people establish a community
  • bold – showing a willingness to take risks; confident and courageous
  • geek – a knowledgeable and obsessive enthusiast
  • gentrification –  is a general term for the arrival of wealthier people in an existing urban district, a related increase in rents and property values, and changes in the district’s character and culture. The term is often used negatively, suggesting the displacement of poor communities by rich outsiders.


Think about it

Answer the questions below. Pause at times indicated in brackets.

  • What do people tend to think when they think about mapping cities? (0:47)
  • What kind of social divisions does the map of San Francisco reveal? (2:55)
  • What three things can we do with the data concerning cities? (5:00)
  • How does Dave define what a city is?
  • What might a map of your city look like?


Practice makes perfect

Fill in the blank spaces with the missing words. Use one word per blank space.

When we think ________ mapping cities, we tend _______ think about roads and streets and buildings, and the settlement narrative that led to their creation, or you might think about the bold vision of ________ urban designer, but there’s other ways to think about mapping cities and how they got to be made. Today, I want to show you a new kind of map. This is not a geographic map. This is a map of ________ relationships between people in my hometown of Baltimore, Maryland, and what you can see here is that each dot represents a person, each line represents ________ relationship between those people, and each color represents a community within ________ network.


Explore it more