Street-network Sprawl in Zitong, 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.

Zitong: city in Sichuan, 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 Zitong, China on the sprawlmap

Most recent snapshot: Taking into account the entire (i.e. aggregate) street network in Zitong as of 2014, the overall level of street-network sprawl is 0.17, which is very well-connected.

Trends in street network construction: The SNDis of street construction for the respective time periods are -0.38, 0.93, -0.6 and nan. Data was not available in 2001-2014.

Quantity of street network construction: The street network in Zitong spans a total of 62 kilometers. It is dominated by roads constructed in 1976-1990. These roads have an SNDi of 0.93, 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 -0.38, 0.64, 0.17 and 0.17. Disconnectivity in Zitong's street network follows a zig-zag trend. In 1975, the city was most disconnected; while it was most connected in 1976-1990.

Zitong and Sichuan 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 Sichuan was at its lowest in 1991-2000.

How do development practices in Zitong fare in comparison to others in Sichuan? out of the 102 cities in Sichuan. Its position in the ranks since 1975 has risen; relative to other cities in Sichuan, street construction in Zitong has become more disconnected. Zitong ranked 84th in 1975, 66th in 1976-1990 and 71st in 1991-2000. There was no ranking in 2001-2014 due to unavailable data.

Zitong 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 Zitong 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 Zitong has become more connected. Zitong ranked 1187th in 1975, 1086th in 1976-1990 and 1200th in 1991-2000. There was no ranking in 2001-2014 due to unavailable data.

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

To date, Zitong is the 99th-most disconnected out of the 102 cities in Sichuan. Its position in the ranks since 1975 has fallen; relative to other cities in Sichuan, the street network in Zitong has become more connected. Zitong ranked 84th in 1975, 85th in 1976-1990, 93rd in 1991-2000 and 99th in 2001-2014.

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

To date, Zitong is the 1517th-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 Zitong has become more connected. Zitong ranked 1187th in 1975, 1295th in 1976-1990, 1469th in 1991-2000 and 1517th in 2001-2014.

As of 2015, Zitong had a built-up area of 2.5 square kilometers, and a population of 57568 people.

These are some other cities with approximately the same population: