Street-network Sprawl in Jiuzhen, 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.

Jiuzhen: city in Fujian, 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 Jiuzhen, China on the sprawlmap

Most recent snapshot: Taking into account the entire (i.e. aggregate) street network in Jiuzhen as of 2014, the overall level of street-network sprawl is 2.71, which is in the 40th to 60th percentile of disconnectedness.

Trends in street network construction: The SNDis of street construction for the respective time periods are 2.99, nan, 0.1 and nan. Data was not available in 1976-1990 and 2001-2014.

Quantity of street network construction: The street network in Jiuzhen spans a total of 130 kilometers. It is dominated by roads constructed prior to 1975. These roads have an SNDi of 2.99, which is in the 40th to 60th percentile of disconnectedness.

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 2.99, 2.89, 2.85 and 2.71. Overall, the SNDi of the aggregate street network has fallen: the street network in Jiuzhen has become more connected. This decrease has quickened: between 1975 and 1976-1990, SNDi fell by 0.1 points, but between 1991-2000 and 2001-2014, it fell by just 0.14.

Jiuzhen and Fujian 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 Fujian peaked in 1991-2000.

How do development practices in Jiuzhen fare in comparison to others in Fujian? out of the 55 cities in Fujian. Jiuzhen ranked 7th in 1975 and 28th in 1991-2000. There was no ranking in 1976-1990 and 2001-2014 due to unavailable data.

Jiuzhen 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 Jiuzhen fare in comparison to others in China? out of the 1651 cities in China. Jiuzhen ranked 249th in 1975 and 1063rd in 1991-2000. There was no ranking in 1976-1990 and 2001-2014 due to unavailable data.

Jiuzhen and Fujian do not follow the same trend in the disconnectivity of their aggregate street networks. The SNDi in Jiuzhen fell steadily, while the SNDi of street constructions in Fujian rose steadily.

To date, Jiuzhen is the 20th-most disconnected out of the 55 cities in Fujian. Its position in the ranks since 1975 has fallen; relative to other cities in Fujian, the street network in Jiuzhen has become more connected. Jiuzhen ranked 7th in 1975, 14th in 1976-1990, 15th in 1991-2000 and 20th in 2001-2014.

Jiuzhen and China do not follow the same trend in the disconnectivity of their aggregate street networks. The SNDi in Jiuzhen fell steadily, while the SNDi of street constructions in China peaked in 1976-1990.

To date, Jiuzhen is the 402nd-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 Jiuzhen has become more connected. Jiuzhen ranked 249th in 1975, 322nd in 1976-1990, 317th in 1991-2000 and 402nd in 2001-2014.

As of 2015, Jiuzhen had a built-up area of 7.37 square kilometers, and a population of 74509 people.

These are some other cities with approximately the same population: