Multimedia project shows the ever-changing shape of cities

The new Atlas of Urban Expansion draws on old and new data to paint a picture of what massive urban growth really means. Above is Quito, Ecuador.

QUITO, Ecuador — At the U. N.’s Habitat III conference on cities here this week, there has been much talk of “urbanization,” “spatial planning” and “urban sprawl.” Those terms may make perfect sense to urban planners, but to others they can be hopeless abstractions.

A multimedia research project released today in Quito aims to change that.

It’s called The Atlas of Urban Expansion, and it’s available online here. It’s a trove of graphics and data visualizations that show the shape of urban growth in 200 global cities with populations over 100,000. One highlight is a feature that draws on historical maps and more contemporary satellite imagery to create mesmerizing animations that show the cities spreading like cancers across the land.

The project is a collaboration among the New York University Urban Expansion Program, UN-Habitat and the Lincoln Institute of Land Policy. The multimedia version of the Atlas builds on a previous book by the same name. “The chief role of this atlas is to look at how fast cities are expanding and how urban peripheries are doing when they expand,” said New York University researcher Shlomo “Solly” Angel.

For example, when a city’s population doubles, the land it consumes triples. According to the atlas’ findings, the land area of cities in less developed countries expanded by a factor of 3.5 between 1990 and 2015. (For the purpose of this project, “city” refers to the urbanized extent of a metropolitan area, as opposed to a single jurisdiction.)

Angel argues that these findings mean that cities must plan for urban expansion by building the necessary infrastructure in advance — rather than creating “greenbelts” or regulatory policies aimed at containing growth that can make cities more unaffordable to live in.

Armando Carbonell, senior fellow at the Lincoln Institute of Land Policy says data from the Atlas has implications for the implementation of the New Urban Agenda, the outcome document of Habitat III that nations will agree to this week.

“The main message coming out of this project,” Carbonell said, “is that the trends we have identified of de-densification and sprawl, are antithetical to the goals of sustainability and climate resilience in the New Urban Agenda.”

I asked Angel to identify several cities from the Atlas that demonstrate challenges or opportunities for cities of the future. He picked three pairs of cities that offer intriguing comparisons when it comes to expansion, density and a city’s overall well being.

Paris and Lagos

The sophisticated French capital and the chaotic Nigerian mega-city might seem like an odd comparison, but they have roughly the same population — just over 11 million. However, despite Nigeria’s rising economy, Paris remains leagues ahead in financial terms, a fact which has huge implications for land consumption. “Paris is 3.5 times larger than Lagos,” Angel explained, “because the amount of money people in Paris have is 10 times the amount of money people in Lagos. So they consume more land.”

Mumbai and Hong Kong

India’s largest city and China’s semi-independent financial hub have approximately the same density. But Hong Kong is much more affluent, and people live in high-rise apartments with better living conditions. “In Mumbai, high density is a problem,” Angel said, referring to the city’s infamous slums. “They live closer to the ground.” As a result, Mumbai is much more overcrowded than Hong Kong. “Density in Mumbai translates into overcrowding,” he summed up. “In Hong Kong, it translates into huge skyscrapers that give everybody enough living space. Where you have a lot of capital and where you can build high rises, it takes care of overcrowding.”

Los Angeles and Shanghai

How cities expand is also something the Atlas demonstrates. Contrary to popular notions that L. A. is a poster child for urban sprawl, Angel argues, “Los Angeles is expanding in a very tight way.” That’s because of the geographic constraints that Los Angeles faces — mountains on one side and the ocean on the other. There’s also basic limitations like the extent of the municipal water supply and the commuting distance in a metro area not known for its public transit. By contrast, China’s financial capital grows via patches appearing on the urban edge. It looks “like measles on the urban periphery” Angel said. In part, this is because some Chinese cities must contend with restrictions on converting land from rural to urban use due to provincial laws designed to protect food security. “When these Chinese cities expand, it’s extremely fragmented,” Angel said, suggesting they should aspire to “more compact expansion, L. A.-style.”

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Gregory Scruggs is a senior correspondent for Citiscope. Full bio

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