Street-network Sprawl in Chenggu, 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.

Chenggu: city in Shaanxi, 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 Chenggu, China on the sprawlmap

Most recent snapshot: Taking into account the entire (i.e. aggregate) street network in Chenggu as of 2014, the overall level of street-network sprawl is 2.22, which is relatively well-connected.

Trends in street network construction: The SNDis of street construction for the respective time periods are 2.14, 2.4, 1.58 and 4.51. Disconnectivity in street construction in Chenggu follows a zig-zag trend. In 1991-2000, street construction was most disconnected, while construction was most connected in 2001-2014.

Quantity of street network construction: The street network in Chenggu spans a total of 90 kilometers. It is dominated by roads constructed in 1976-1990. These roads have an SNDi of 2.4, 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 2.14, 2.31, 2.21 and 2.22. Disconnectivity in Chenggu's street network follows a zig-zag trend. In 1975, the city was most disconnected; while it was most connected in 1976-1990.

Chenggu and Shaanxi do not follow the same trend in the disconnectivity of their street network constructions. The SNDi in Chenggu followed a zig-zag trend with an overall increase, while the SNDi of street constructions in Shaanxi was at its lowest in 1976-1990.

How do development practices in Chenggu fare in comparison to others in Shaanxi? Most recently in 2001-2014, street construction in Chenggu was the 4th-most disconnected out of the 60 cities in Shaanxi. Its position in the ranks since 1975 has risen; relative to other cities in Shaanxi, street construction in Chenggu has become more disconnected. Chenggu ranked 23rd in 1975, 16th in 1976-1990, 24th in 1991-2000 and 4th in 2001-2014.

Chenggu 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 Chenggu fare in comparison to others in China? Most recently in 2001-2014, street construction in Chenggu was the 139th-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 Chenggu has become more disconnected. Chenggu ranked 454th in 1975, 491st in 1976-1990, 611th in 1991-2000 and 139th in 2001-2014.

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

To date, Chenggu is the 24th-most disconnected out of the 60 cities in Shaanxi. Its position in the ranks since 1975 has fallen; relative to other cities in Shaanxi, the street network in Chenggu has become more connected. Chenggu ranked 23rd in 1975, 20th in 1976-1990, 21st in 1991-2000 and 24th in 2001-2014.

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

To date, Chenggu is the 609th-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 Chenggu has become more connected. Chenggu ranked 454th in 1975, 526th in 1976-1990, 567th in 1991-2000 and 609th in 2001-2014.

As of 2015, Chenggu had a built-up area of 4.91 square kilometers, and a population of 93253 people.

These are some other cities with approximately the same population: