Street-network Sprawl in Changyuan, 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.

Changyuan: city in Henan, 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 Changyuan, China on the sprawlmap

Most recent snapshot: Taking into account the entire (i.e. aggregate) street network in Changyuan as of 2014, the overall level of street-network sprawl is 2.16, which is relatively well-connected.

Trends in street network construction: The SNDis of street construction for the respective time periods are 3.25, 2.0, 3.27 and 2.16. Disconnectivity in street construction in Changyuan follows a zig-zag trend. In 1976-1990, street construction was most disconnected, while construction was most connected in 1991-2000.

Quantity of street network construction: The street network in Changyuan spans a total of 256 kilometers. It is dominated by roads constructed in 2001-2014. These roads have an SNDi of 2.16, 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 3.25, 2.11, 2.19 and 2.16. Disconnectivity in Changyuan's street network follows a zig-zag trend. In 1976-1990, the city was most disconnected; while it was most connected in 1975.

Changyuan and Henan do not follow the same trend in the disconnectivity of their street network constructions. The SNDi in Changyuan followed a zig-zag trend with an overall decrease, while the SNDi of street constructions in Henan peaked in 1991-2000.

How do development practices in Changyuan fare in comparison to others in Henan? Most recently in 2001-2014, street construction in Changyuan was the 21st-most disconnected out of the 118 cities in Henan. Its position in the ranks since 1975 has fallen; relative to other cities in Henan, street construction in Changyuan has become more connected. Changyuan ranked 6th in 1975, 20th in 1976-1990, 10th in 1991-2000 and 21st in 2001-2014.

Changyuan and China do not follow the same trend in the disconnectivity of their street network constructions. The SNDi in Changyuan followed a zig-zag trend with an overall decrease, while the SNDi of street constructions in China followed a zig-zag trend with an overall decrease.

How do development practices in Changyuan fare in comparison to others in China? Most recently in 2001-2014, street construction in Changyuan was the 622nd-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 Changyuan has become more connected. Changyuan ranked 201st in 1975, 659th in 1976-1990, 202nd in 1991-2000 and 622nd in 2001-2014.

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

To date, Changyuan is the 14th-most disconnected out of the 118 cities in Henan. Its position in the ranks since 1975 has fallen; relative to other cities in Henan, the street network in Changyuan has become more connected. Changyuan ranked 6th in 1975, 15th in 1976-1990, 14th in 1991-2000 and 14th in 2001-2014.

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

To date, Changyuan is the 627th-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 Changyuan has become more connected. Changyuan ranked 201st in 1975, 611th in 1976-1990, 574th in 1991-2000 and 627th in 2001-2014.

As of 2015, Changyuan had a built-up area of 23.88 square kilometers, and a population of 145830 people.

These are some other cities with approximately the same population: