Street-network Sprawl in Wanzai, 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.

Wanzai: city in Jiangxi, 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 Wanzai, China on the sprawlmap

Most recent snapshot: Taking into account the entire (i.e. aggregate) street network in Wanzai as of 2014, the overall level of street-network sprawl is 0.26, which is very well-connected.

Trends in street network construction: The SNDis of street construction for the respective time periods are 0.41, -0.77, nan and 0.58. Data was not available in 1991-2000.

Quantity of street network construction: The street network in Wanzai spans a total of 96 kilometers. It is dominated by roads constructed in 2001-2014. These roads have an SNDi of 0.58, 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 0.41, 0.04, 0.04 and 0.26. The SNDi of the aggregate street network in fell at first, but Wanzai has worsened in disconnectivity since 1990.

Wanzai and Jiangxi 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 Jiangxi peaked in 1976-1990.

How do development practices in Wanzai fare in comparison to others in Jiangxi? Most recently in 2001-2014, street construction in Wanzai was the 58th-most disconnected out of the 74 cities in Jiangxi. Its position in the ranks since 1975 has fallen; relative to other cities in Jiangxi, street construction in Wanzai has become more connected. Wanzai ranked 55th in 1975, 69th in 1976-1990 and 58th in 2001-2014. There was no ranking in 1991-2000 due to unavailable data.

Wanzai 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 Wanzai fare in comparison to others in China? Most recently in 2001-2014, street construction in Wanzai was the 1150th-most disconnected 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 Wanzai has become more connected. Wanzai ranked 1023rd in 1975, 1457th in 1976-1990 and 1150th in 2001-2014. There was no ranking in 1991-2000 due to unavailable data.

Wanzai and Jiangxi do not follow the same trend in the disconnectivity of their aggregate street networks. The SNDi in Wanzai was at its lowest in 1976-1990, while the SNDi of street constructions in Jiangxi peaked in 1976-1990.

To date, Wanzai is the 70th-most disconnected out of the 74 cities in Jiangxi. Its position in the ranks since 1975 has fallen; relative to other cities in Jiangxi, the street network in Wanzai has become more connected. Wanzai ranked 55th in 1975, 67th in 1976-1990, 71st in 1991-2000 and 70th in 2001-2014.

Wanzai and China do not follow the same trend in the disconnectivity of their aggregate street networks. The SNDi in Wanzai was at its lowest in 1976-1990, while the SNDi of street constructions in China peaked in 1976-1990.

To date, Wanzai is the 1489th-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 Wanzai has become more connected. Wanzai ranked 1023rd in 1975, 1465th in 1976-1990, 1505th in 1991-2000 and 1489th in 2001-2014.

As of 2015, Wanzai had a built-up area of 6.33 square kilometers, and a population of 103300 people.

These are some other cities with approximately the same population: