Street-network Sprawl in Changtu, 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.

Changtu: city in Liaoning, 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 Changtu, China on the sprawlmap

Most recent snapshot: Taking into account the entire (i.e. aggregate) street network in Changtu as of 2014, the overall level of street-network sprawl is 1.59, which is relatively well-connected.

Trends in street network construction: The SNDis of street construction for the respective time periods are 0.02, 2.37, nan and 5.56. Data was not available in 1991-2000.

Quantity of street network construction: The street network in Changtu spans a total of 81 kilometers. It is dominated by roads constructed in 1976-1990. These roads have an SNDi of 2.37, 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 0.02, 1.07, 1.07 and 1.59. Overall, the SNDi of the aggregate street network has risen: the street network in Changtu has become more disconnected. This increase has slowed: between 1975 and 1976-1990, SNDi rose by 1.05 points, but between 1991-2000 and 2001-2014, it rose by just 0.52.

Changtu and Liaoning 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 Liaoning peaked in 1976-1990.

How do development practices in Changtu fare in comparison to others in Liaoning? Most recently in 2001-2014, street construction in Changtu was the 4th-most disconnected out of the 52 cities in Liaoning. Its position in the ranks since 1975 has risen; relative to other cities in Liaoning, street construction in Changtu has become more disconnected. Changtu ranked 45th in 1975, 22nd in 1976-1990 and 4th in 2001-2014. There was no ranking in 1991-2000 due to unavailable data.

Changtu 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 Changtu fare in comparison to others in China? Most recently in 2001-2014, street construction in Changtu was the 70th-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 Changtu has become more disconnected. Changtu ranked 1109th in 1975, 499th in 1976-1990 and 70th in 2001-2014. There was no ranking in 1991-2000 due to unavailable data.

Changtu and Liaoning do not follow the same trend in the disconnectivity of their aggregate street networks. The SNDi in Changtu rose steadily, while the SNDi of street constructions in Liaoning peaked in 1991-2000.

To date, Changtu is the 23rd-most disconnected out of the 52 cities in Liaoning. Its position in the ranks since 1975 has risen; relative to other cities in Liaoning, the street network in Changtu has become more disconnected. Changtu ranked 45th in 1975, 34th in 1976-1990, 35th in 1991-2000 and 23rd in 2001-2014.

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

To date, Changtu is the 911th-most disconnected out of the 1651 cities in China. Its position in the ranks since 1975 has risen; relative to other cities in China, the street network in Changtu has become more disconnected. Changtu ranked 1109th in 1975, 1099th in 1976-1990, 1118th in 1991-2000 and 911th in 2001-2014.

As of 2015, Changtu had a built-up area of 10.77 square kilometers, and a population of 71136 people.

These are some other cities with approximately the same population: