LASIG and street networks evolution in the Scientific American

 2012 EPFL

2012 EPFL

Emanuele Strano, a doctoral candidate at LASIG, authored a study published in Nature’s Scientific Reports to examine how a group of Italian villages evolved into suburbs outside Milan today. Such a study may eventually help urban planners optimize future developments. The magazine " Scientific American " devoted a popularization article to this study.

The world’s cities are absorbing one million additional people every week - and by 2030, they could consume an extra 1.5 million square kilometers of land. What would be the best ways for those cities to grow? The present study takes a step toward that essential understanding. Strano and colleagues - computer scientists, mathematicians, physicists and urban scholars - teamed up to provide the first quantitative analysis of how unplanned street networks evolve over time. They studied the growth of Groane, a large urban area located north of Milan. Using maps dating as far back as 1833, the researchers modeled the urban sprawl process as Groane developed from agricultural land into a residential and industrial area, and then into a postindustrial suburb of the Milanese metropolis. At seven time points between 1833 and 2007 the researchers used geospatial data and scripts to construct digital maps that treat the street system as a network. The network analyses performed revealed that although Groane had never been subjected to large-scale planning efforts, the street network evolved to be more uniform in size and density, and its predominant shape shifted from triangular to rectangular. Rectangular street networks may arise organically, the authors say, simply because they offer more efficient pathways and allow for more organized subdivision of land.