Street-network Sprawl in Nanning, 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.

Nanning: city in Guangxi, 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 Nanning, China on the sprawlmap

Most recent snapshot: Taking into account the entire (i.e. aggregate) street network in Nanning as of 2014, the overall level of street-network sprawl is 1.7, which is relatively well-connected.

Trends in street network construction: The SNDis of street construction for the respective time periods are 1.33, 2.02, 1.19 and 2.66. Disconnectivity in street construction in Nanning follows a zig-zag trend. In 1991-2000, street construction was most disconnected, while construction was most connected in 2001-2014.

Quantity of street network construction: The street network in Nanning spans a total of 1306 kilometers. It is dominated by roads constructed in 1976-1990. These roads have an SNDi of 2.02, which is relatively well-connected.

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 1.33, 1.79, 1.64 and 1.7. Disconnectivity in Nanning's street network follows a zig-zag trend. In 1975, the city was most disconnected; while it was most connected in 1976-1990.

Nanning and Guangxi follow the same trend in the disconnectivity of their street network constructions. The SNDi for both of these followed a zig-zag trend with an overall increase.

How do development practices in Nanning fare in comparison to others in Guangxi? Most recently in 2001-2014, street construction in Nanning was the 20th-most disconnected out of the 53 cities in Guangxi. Its position in the ranks since 1975 has risen; relative to other cities in Guangxi, street construction in Nanning has become more disconnected. Nanning ranked 27th in 1975, 29th in 1976-1990, 29th in 1991-2000 and 20th in 2001-2014.

Nanning and China follow the same trend in the disconnectivity of their street network constructions. The SNDi for both of these followed a zig-zag trend with an overall increase.

How do development practices in Nanning fare in comparison to others in China? Most recently in 2001-2014, street construction in Nanning was the 466th-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 Nanning has become more disconnected. Nanning ranked 717th in 1975, 656th in 1976-1990, 726th in 1991-2000 and 466th in 2001-2014.

Nanning and Guangxi do not follow the same trend in the disconnectivity of their aggregate street networks. The SNDi in Nanning followed a zig-zag trend with an overall increase, while the SNDi of street constructions in Guangxi peaked in 1976-1990.

To date, Nanning is the 31st-most disconnected out of the 53 cities in Guangxi. Its position in the ranks since 1975 has fallen; relative to other cities in Guangxi, the street network in Nanning has become more connected. Nanning ranked 27th in 1975, 29th in 1976-1990, 31st in 1991-2000 and 31st in 2001-2014.

Nanning and China do not follow the same trend in the disconnectivity of their aggregate street networks. The SNDi in Nanning followed a zig-zag trend with an overall increase, while the SNDi of street constructions in China peaked in 1976-1990.

To date, Nanning is the 856th-most disconnected out of the 1651 cities in China. Its position in the ranks since 1975 has fallen; relative to other cities in China, the street network in Nanning has become more connected. Nanning ranked 717th in 1975, 751st in 1976-1990, 829th in 1991-2000 and 856th in 2001-2014.

As of 2015, Nanning had a built-up area of 132.4 square kilometers, and a population of 2372502 people.

These are some other cities with approximately the same population: