Street-network Sprawl in Nanling, China

What is Street-network sprawl?

Street-network Sprawl is a way to measure urban sprawl, worldwide, through the connectedness of the streets. Less sprawl means more connected, more walkable streets. Well-connected streets – like New York City’s grid – are more walkable and can be served by public transit.

The street network is permanent, and its connectivity affects the livability and environmental footprint of cities for decades and centuries to come. In places with more connected streets, residents drive less and walk more. A well-connected street network is associated with better outcomes for health, the environment, sustainable consumption, social integration, and equity.

We can quantify how connected street networks are with the Street Network Disconnectedness Index (SNDi).

SNDi -- our measure of street-network sprawl (disconnectedness)

The SNDi is a comprehensive measurement of “sprawl”. It captures:

A higher SNDi means less-connected streets – i.e., more sprawl. For the 10137 cities in our dataset, the average SNDi is 2.25, with half of the cities' SNDis falling between 1.08 and 3.25.

More information on the sprawl index can be found in these research papers:

To see the state of street-network sprawl across the globe, visit the sprawlmap.

Nanling: city in Anhui, China

What exactly constitutes the spatial extent of the city? For these aggregations, we used the Global Human Settlement Layer Urban Center Database (GHS-UCDB) to define the boundaries of the city. These cities -- or urban centers -- cover areas that are densely populated and built-up, and so may extend beyond the spatial borders of these cities that we may be familiar with. The GHS area is shaded in blue.

View Nanling, China on the sprawlmap

Most recent snapshot: Taking into account the entire (i.e. aggregate) street network in Nanling as of 2014, the overall level of street-network sprawl is 1.16, which is relatively well-connected.

Trends in street network construction: The SNDis of street construction for the respective time periods are nan, 0.51, 2.1 and 1.51. Data was not available in 1975.

Quantity of street network construction: The street network in Nanling spans a total of 125 kilometers. It is dominated by roads constructed prior to 1975. These roads have an SNDi of nan, which is highly disconnected.

Effect on the aggregate network: New construction in each period adds to the total stock of streets, but does not change streets that have already been built. Therefore, it has a limited effect on the street network as a whole. The SNDis of the aggregate street network in the respective time periods are nan, 0.51, 0.65 and 1.16. Data was not available in 1975.

Nanling and Anhui do not follow the same trend in the disconnectivity of their street network constructions. There was not enough data from the city, while the SNDi of street constructions in Anhui fell steadily.

How do development practices in Nanling fare in comparison to others in Anhui? Most recently in 2001-2014, street construction in Nanling was the 22nd-most disconnected out of the 65 cities in Anhui. Its position in the ranks since 1975 has risen; relative to other cities in Anhui, street construction in Nanling has become more disconnected. Nanling ranked 49th in 1976-1990, 11th in 1991-2000 and 22nd in 2001-2014. There was no ranking in 1975 due to unavailable data.

Nanling and China do not follow the same trend in the disconnectivity of their street network constructions. There was not enough data from the city, while the SNDi of street constructions in China followed a zig-zag trend with an overall decrease.

How do development practices in Nanling fare in comparison to others in China? Most recently in 2001-2014, street construction in Nanling was the 855th-most disconnected out of the 1651 cities in China. Its position in the ranks since 1975 has risen; relative to other cities in China, street construction in Nanling has become more disconnected. Nanling ranked 1228th in 1976-1990, 455th in 1991-2000 and 855th in 2001-2014. There was no ranking in 1975 due to unavailable data.

Nanling and Anhui do not follow the same trend in the disconnectivity of their aggregate street networks. There was not enough data from the city, while the SNDi of street constructions in Anhui fell steadily.

To date, Nanling is the 31st-most disconnected out of the 65 cities in Anhui. Its position in the ranks since 1975 has risen; relative to other cities in Anhui, the street network in Nanling has become more disconnected. Nanling ranked 49th in 1976-1990, 43rd in 1991-2000 and 31st in 2001-2014. There was no ranking in 1975 due to unavailable data.

Nanling and China do not follow the same trend in the disconnectivity of their aggregate street networks. There was not enough data from the city, while the SNDi of street constructions in China peaked in 1976-1990.

To date, Nanling is the 1140th-most disconnected out of the 1651 cities in China. Its position in the ranks since 1975 has risen; relative to other cities in China, the street network in Nanling has become more disconnected. Nanling ranked 1338th in 1976-1990, 1303rd in 1991-2000 and 1140th in 2001-2014. There was no ranking in 1975 due to unavailable data.

As of 2015, Nanling had a built-up area of 7.93 square kilometers, and a population of 98450 people.

These are some other cities with approximately the same population: