Street-network Sprawl in Anqing, 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.

Anqing: city in Anhui, 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 Anqing, China on the sprawlmap

Most recent snapshot: Taking into account the entire (i.e. aggregate) street network in Anqing as of 2014, the overall level of street-network sprawl is 0.78, which is relatively well-connected.

Trends in street network construction: The SNDis of street construction for the respective time periods are 0.22, 1.11, 0.41 and 1.98. Disconnectivity in street construction in Anqing follows a zig-zag trend. In 1975, street construction was most disconnected, while construction was most connected in 2001-2014.

Quantity of street network construction: The street network in Anqing spans a total of 399 kilometers. The period with the greatest volume of street construction was 1975. These roads have an SNDi of 0.22, which is very 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 0.22, 0.49, 0.48 and 0.78. Disconnectivity in Anqing's street network follows a zig-zag trend. In 1975, the city was most disconnected; while it was most connected in 2001-2014.

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

How do development practices in Anqing fare in comparison to others in Anhui? Most recently in 2001-2014, street construction in Anqing was the 15th-most disconnected out of the 65 cities in Anhui. Its position in the ranks since 1975 has risen; relative to other cities in Anhui, street construction in Anqing has become more disconnected. Anqing ranked 36th in 1975, 35th in 1976-1990, 40th in 1991-2000 and 15th in 2001-2014.

Anqing 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 Anqing fare in comparison to others in China? Most recently in 2001-2014, street construction in Anqing was the 674th-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 Anqing has become more disconnected. Anqing ranked 1068th in 1975, 1030th in 1976-1990, 979th in 1991-2000 and 674th in 2001-2014.

Anqing and Anhui do not follow the same trend in the disconnectivity of their aggregate street networks. The SNDi in Anqing followed a zig-zag trend with an overall increase, while the SNDi of street constructions in Anhui fell steadily.

To date, Anqing is the 41st-most disconnected out of the 65 cities in Anhui. Its position in the ranks since 1975 has fallen; relative to other cities in Anhui, the street network in Anqing has become more connected. Anqing ranked 36th in 1975, 50th in 1976-1990, 50th in 1991-2000 and 41st in 2001-2014.

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

To date, Anqing is the 1324th-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 Anqing has become more connected. Anqing ranked 1068th in 1975, 1344th in 1976-1990, 1380th in 1991-2000 and 1324th in 2001-2014.

As of 2015, Anqing had a built-up area of 37.52 square kilometers, and a population of 548114 people.

These are some other cities with approximately the same population:

For some related information about population, urban extent and density, and roads, visit the Atlas of Urban Expansion.