Street-network Sprawl in Xiangyin, 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.

Xiangyin: city in Hunan, 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 Xiangyin, China on the sprawlmap

Most recent snapshot: Taking into account the entire (i.e. aggregate) street network in Xiangyin as of 2014, the overall level of street-network sprawl is 1.23, which is relatively well-connected.

Trends in street network construction: The SNDis of street construction for the respective time periods are 1.78, 0.94, nan and 0.48. Data was not available in 1991-2000.

Quantity of street network construction: The street network in Xiangyin spans a total of 163 kilometers. The period with the greatest volume of street construction was 1976-1990. These roads have an SNDi of 0.94, 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 1.78, 1.38, 1.49 and 1.23. Disconnectivity in Xiangyin's street network follows a zig-zag trend. In 2001-2014, the city was most disconnected; while it was most connected in 1975.

Xiangyin and Hunan do not follow the same trend in the disconnectivity of their street network constructions. There was not enough data from the city, while the SNDi of street constructions in Hunan followed a zig-zag trend with an overall decrease.

How do development practices in Xiangyin fare in comparison to others in Hunan? Most recently in 2001-2014, street construction in Xiangyin was the 68th-most disconnected out of the 95 cities in Hunan. Its position in the ranks since 1975 has fallen; relative to other cities in Hunan, street construction in Xiangyin has become more connected. Xiangyin ranked 39th in 1975, 70th in 1976-1990 and 68th in 2001-2014. There was no ranking in 1991-2000 due to unavailable data.

Xiangyin and China do not follow the same trend in the disconnectivity of their street network constructions. There was not enough data from the city, while the SNDi of street constructions in China followed a zig-zag trend with an overall decrease.

How do development practices in Xiangyin fare in comparison to others in China? Most recently in 2001-2014, street construction in Xiangyin was the 1177th-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 Xiangyin has become more connected. Xiangyin ranked 561st in 1975, 1081st in 1976-1990 and 1177th in 2001-2014. There was no ranking in 1991-2000 due to unavailable data.

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

To date, Xiangyin is the 71st-most disconnected out of the 95 cities in Hunan. Its position in the ranks since 1975 has fallen; relative to other cities in Hunan, the street network in Xiangyin has become more connected. Xiangyin ranked 39th in 1975, 67th in 1976-1990, 62nd in 1991-2000 and 71st in 2001-2014.

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

To date, Xiangyin is the 1095th-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 Xiangyin has become more connected. Xiangyin ranked 561st in 1975, 947th in 1976-1990, 911th in 1991-2000 and 1095th in 2001-2014.

As of 2015, Xiangyin had a built-up area of 7.71 square kilometers, and a population of 235983 people.

These are some other cities with approximately the same population: