Mobile Landscapes: Using Location Data From Cell-phones for Urban Analysis

Ratti C, Pulselli R M, Williams S, Frenchman D, 2006, “Mobile Landscapes: using location data from cell phones for urban analysis” Environment and Planning B: Planning and Design 33(5) 727 – 748

In this seminal paper, Carlo Ratti defines the research in the application of Location-Based Services to urban studies. At first he summarizes the state of the art in location determination techniques and their implication related to privacy. Then, he presents the potential from the results of case study in the metropolitan area of Milan, Italy.

In Milan, Ratti explored the way GSM traces can contribute to urban understanding. In a 16 days temporal framework, some patterns could be extracted such as those happening with day/night and working/weekend periodicity. The information gleaned from a urban studies perspectives mainly rely on geovisualizations (e.g. showing the intensity of traffic at a given position in space with thermorgraphy maps). One use could be to infer the “character” of a neighborhood. For example, neighborhoods with high evening and early morning cellphone traffic are likely to have a stronger residential character. An interesting aspect to see the variation in time above maps would be to estimate the flows in and out of the city, such as patterns of daily communities, weekday versus weekend activities, holiday movements.

I could plot something similar with the accuracy used over the time of the day for a specific neighborhood.

Maps showing areas with different cell phone call density in the metropolitan region of Milan. Data between 4 and 8pm.

Relation to my thesis: Ratti mentions that “the pervasive deployment of new technologies is transorming urban patterns, making the more complex and fluid. Greater mobility and freedom are changing the way living and using public and private spaces“. Similarly there is a growing number of data to understand this transformation. Part of my current experiment joins this effort on the use of new technologies to describe cities. That is, how can explicitly geotagged information contribute to urban understanding. I believe it can highlight a number of interesting patterns for tourists and citizens to view a city, such as those happening with day/night and working/weekend periodicity.

This type of investigation based on spatio-temporal traces of people and crowds relate to the work of Raper and Mountain, and Nathan Eagle, as well as for years in Transportation Research.