Street-network Sprawl in Dongchuan, 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.

Dongchuan: city in Yunnan, 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 Dongchuan, China on the sprawlmap

Most recent snapshot: Taking into account the entire (i.e. aggregate) street network in Dongchuan as of 2014, the overall level of street-network sprawl is 3.82, which is highly disconnected.

Trends in street network construction: The SNDis of street construction for the respective time periods are 0.25, 5.72, 2.82 and 4.64. Disconnectivity in street construction in Dongchuan follows a zig-zag trend. In 1975, street construction was most disconnected, while construction was most connected in 1976-1990.

Quantity of street network construction: The street network in Dongchuan spans a total of 97 kilometers. It is dominated by roads constructed in 2001-2014. These roads have an SNDi of 4.64, 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 0.25, 2.67, 2.7 and 3.82. Overall, the SNDi of the aggregate street network has risen: the street network in Dongchuan has become more disconnected. This increase has slowed: between 1975 and 1976-1990, SNDi rose by 2.41 points, but between 1991-2000 and 2001-2014, it rose by just 1.12.

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

How do development practices in Dongchuan fare in comparison to others in Yunnan? Most recently in 2001-2014, street construction in Dongchuan was the 11th-most disconnected out of the 56 cities in Yunnan. Its position in the ranks since 1975 has risen; relative to other cities in Yunnan, street construction in Dongchuan has become more disconnected. Dongchuan ranked 38th in 1975, 2nd in 1976-1990, 17th in 1991-2000 and 11th in 2001-2014.

Dongchuan and China follow the same trend in the disconnectivity of their street network constructions. The SNDi for both of these followed a zig-zag trend with an overall increase.

How do development practices in Dongchuan fare in comparison to others in China? Most recently in 2001-2014, street construction in Dongchuan was the 128th-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 Dongchuan has become more disconnected. Dongchuan ranked 1057th in 1975, 37th in 1976-1990, 267th in 1991-2000 and 128th in 2001-2014.

Dongchuan and Yunnan follow the same trend in the disconnectivity of their aggregate street networks. The SNDi for both of these rose steadily.

To date, Dongchuan is the 7th-most disconnected out of the 56 cities in Yunnan. Its position in the ranks since 1975 has risen; relative to other cities in Yunnan, the street network in Dongchuan has become more disconnected. Dongchuan ranked 38th in 1975, 15th in 1976-1990, 16th in 1991-2000 and 7th in 2001-2014.

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

To date, Dongchuan is the 123rd-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 Dongchuan has become more disconnected. Dongchuan ranked 1057th in 1975, 381st in 1976-1990, 360th in 1991-2000 and 123rd in 2001-2014.

As of 2015, Dongchuan had a built-up area of 5.36 square kilometers, and a population of 83496 people.

These are some other cities with approximately the same population: