Uncovering the Hidden Layouts of Brazil’s Favelas

Nearly 1 billion people around the world have made their homes in informal settlements built spontaneously without any official urban planning. These areas often lack access to basic infrastructure services such as water, sanitation and sewage, and because these residents do not have legal addresses, it can be difficult for them to utilize public services like schools and health centers.

In Brazil, these informal settlements are known as favelas. These communities, which total more than 1,000 across the country, have become so complex that even satellite imagery from Google Street View and open-source mapping cannot provide an in-depth view of the landscape. 

“Favela residents have developed ingenious and responsive ways to build their own urban systems,” said Carlo Ratti, director at MIT Senseable City Lab and professor of practice at Carlo Ratti Associati. “This bottom-up planning process and the complex architectural forms it produces can challenge the standard way of designing cities.”

To map out these favelas, which have become an intricate part of Brazil’s urban landscape and home to more than 1.5 million people, the Massachusetts Institute of Technology (MIT) Senseable City Lab has partnered with Washington Fajardo, the secretary of urban development for the city of Rio de Janeiro, to map out the structures and layouts of the streets of Rocinha, Rio’s largest favela.

Gaining Insight From Hidden Territories

The project, called Favelas 4D, will rely on lidar (light detection and ranging) scans taken at the street level to create 3D images of the environment that provide invaluable insights into the area’s morphology.

“Lidar uses a laser pulse to measure distances, mapping minuscule points to locations in space to create a data set that depicts the environment in 3D with incredible precision — around 300,000 data points at street level are generated every second,” said Ratti.

The technology can analyze street width and elevation, the density of facades, variance in facade height and street canyon (the ratio of facade height to street width).

Normally, only 23% of the roads in Rocinha are observable on Google Street View, but lidar technology can create such detailed maps of the dense environments that previously unseen streets will be visible. 

Overcoming Problems in Built-Up Environments

Adding formerly unseen streets to Google Maps is not the only goal of this massive undertaking, however. The lidar scans will also produce models of the favelas, which can be used to find patterns in the area and give insights that can be used to improve safety, planning and management of the environments.

“We are still in the process of running different types of analyses — from structural stability of the individual homes to light and wind simulation —  to ascertain how the urban fabric can be made healthier,” said Ratti.

In addition, the scans will also provide important information about the living conditions within favelas, which tend to be built on unstable terrain with a  risk of landslides. Water and air quality are often poor due to limited infrastructure and the extreme density and lack of sun and air in these communities, which can drive high instances of tuberculosis cases.

“From the standpoint of project managers or urban planners, they will be better informed in optimizing the favelas’ living conditions, like adding stairs at the right spots or removing redundant structures to introduce more air and sunlight and integrating them into the formal city,” said Ratti.

Extending the Technology Outside Favelas

Lidar mapping technology can be used to improve development practices and methods of city-building overall. For example, data collected via Favelas 4D can be used to develop proper infrastructure for residents and to assign property titles to residents from the identification of the building.

“The scans could serve as the basis for the creation of property records, which could in turn be managed via blockchain so that their transfer could be done with minimum costs and bureaucracy,” explained Ratti.

But as this is a relatively new concept, there are still concerns that need to be addressed with residents such as data privacy questions. Ratti suggests project managers could set up a feedback loop with residents about their concerns so they can have input into any new developments.   

As this technology evolves, Ratti hopes Favela 4D will be used in many other informal settlements around the world.   

“Scanning more favelas, shantytowns and refugee camps will help us understand the communities that have been marginalized and find the best way to connect them with the planned segments of the city,” said Ratti. “This, I believe, is crucial for our society in the long run.”