Street-network Sprawl in Nanzheng, 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.

Nanzheng: city in Shaanxi, 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 Nanzheng, China on the sprawlmap

Most recent snapshot: Taking into account the entire (i.e. aggregate) street network in Nanzheng as of 2014, the overall level of street-network sprawl is 0.99, which is relatively well-connected.

Trends in street network construction: The SNDis of street construction for the respective time periods are 2.18, 0.47, 1.79 and nan. Data was not available in 2001-2014.

Quantity of street network construction: The street network in Nanzheng spans a total of 30 kilometers. It is dominated by roads constructed in 1976-1990. These roads have an SNDi of 0.47, 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 2.18, 0.9, 0.99 and 0.99. Disconnectivity in Nanzheng's street network follows a zig-zag trend. In 1976-1990, the city was most disconnected; while it was most connected in 1975.

Nanzheng and Shaanxi 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 Shaanxi was at its lowest in 1976-1990.

How do development practices in Nanzheng fare in comparison to others in Shaanxi? out of the 60 cities in Shaanxi. Its position in the ranks since 1975 has risen; relative to other cities in Shaanxi, street construction in Nanzheng has become more disconnected. Nanzheng ranked 21st in 1975, 40th in 1976-1990 and 20th in 1991-2000. There was no ranking in 2001-2014 due to unavailable data.

Nanzheng 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 Nanzheng fare in comparison to others in China? out of the 1651 cities in China. Its position in the ranks since 1975 has fallen; relative to other cities in China, street construction in Nanzheng has become more connected. Nanzheng ranked 440th in 1975, 1242nd in 1976-1990 and 555th in 1991-2000. There was no ranking in 2001-2014 due to unavailable data.

Nanzheng and Shaanxi do not follow the same trend in the disconnectivity of their aggregate street networks. The SNDi in Nanzheng followed a zig-zag trend with an overall decrease, while the SNDi of street constructions in Shaanxi was at its lowest in 1991-2000.

To date, Nanzheng is the 43rd-most disconnected out of the 60 cities in Shaanxi. Its position in the ranks since 1975 has fallen; relative to other cities in Shaanxi, the street network in Nanzheng has become more connected. Nanzheng ranked 21st in 1975, 40th in 1976-1990, 40th in 1991-2000 and 43rd in 2001-2014.

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

To date, Nanzheng is the 1222nd-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 Nanzheng has become more connected. Nanzheng ranked 440th in 1975, 1182nd in 1976-1990, 1155th in 1991-2000 and 1222nd in 2001-2014.

As of 2015, Nanzheng had a built-up area of 2.25 square kilometers, and a population of 76317 people.

These are some other cities with approximately the same population: