Street-network Sprawl in Danjiangkou, 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.

Danjiangkou: city in Hubei, 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 Danjiangkou, China on the sprawlmap

Most recent snapshot: Taking into account the entire (i.e. aggregate) street network in Danjiangkou as of 2014, the overall level of street-network sprawl is 3.24, 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 0.86, 3.4, 3.47 and 5.04. In each period, new street development in Danjiangkou steadily grows more disconnected than in the last. This increase has slowed: between 1975 and 1976-1990, SNDi rose by 2.54 points, but between 1991-2000 and 2001-2014, it rose by just 1.57.

Quantity of street network construction: The street network in Danjiangkou spans a total of 134 kilometers. It is dominated by roads constructed in 2001-2014. These roads have an SNDi of 5.04, which is highly disconnected.

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 0.86, 2.84, 2.63 and 3.24. Disconnectivity in Danjiangkou's street network follows a zig-zag trend. In 1975, the city was most disconnected; while it was most connected in 2001-2014.

Danjiangkou and Hubei do not follow the same trend in the disconnectivity of their street network constructions. The SNDi in Danjiangkou rose steadily, while the SNDi of street constructions in Hubei peaked in 1976-1990.

How do development practices in Danjiangkou fare in comparison to others in Hubei? Most recently in 2001-2014, street construction in Danjiangkou was the 8th-most disconnected out of the 80 cities in Hubei. Its position in the ranks since 1975 has risen; relative to other cities in Hubei, street construction in Danjiangkou has become more disconnected. Danjiangkou ranked 40th in 1975, 6th in 1976-1990, 14th in 1991-2000 and 8th in 2001-2014.

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

How do development practices in Danjiangkou fare in comparison to others in China? Most recently in 2001-2014, street construction in Danjiangkou was the 100th-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 Danjiangkou has become more disconnected. Danjiangkou ranked 872nd in 1975, 230th in 1976-1990, 174th in 1991-2000 and 100th in 2001-2014.

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

To date, Danjiangkou is the 12th-most disconnected out of the 80 cities in Hubei. Its position in the ranks since 1975 has risen; relative to other cities in Hubei, the street network in Danjiangkou has become more disconnected. Danjiangkou ranked 40th in 1975, 14th in 1976-1990, 18th in 1991-2000 and 12th in 2001-2014.

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

To date, Danjiangkou is the 226th-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 Danjiangkou has become more disconnected. Danjiangkou ranked 872nd in 1975, 343rd in 1976-1990, 387th in 1991-2000 and 226th in 2001-2014.

As of 2015, Danjiangkou had a built-up area of 11.34 square kilometers, and a population of 155520 people.

These are some other cities with approximately the same population: