Street-network Sprawl in Gaosha, 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.

Gaosha: 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 Gaosha, China on the sprawlmap

Most recent snapshot: Taking into account the entire (i.e. aggregate) street network in Gaosha as of 2014, the overall level of street-network sprawl is 0.14, which is very well-connected.

Trends in street network construction: The SNDis of street construction for the respective time periods are 0.71, -0.17, 0.88 and 0.37. Disconnectivity in street construction in Gaosha follows a zig-zag trend. In 1976-1990, street construction was most disconnected, while construction was most connected in 1991-2000.

Quantity of street network construction: The street network in Gaosha spans a total of 56 kilometers. The period with the greatest volume of street construction was 2001-2014. These roads have an SNDi of 0.37, 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 0.71, 0.08, 0.15 and 0.14. Disconnectivity in Gaosha's street network follows a zig-zag trend. In 1976-1990, the city was most disconnected; while it was most connected in 1975.

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

How do development practices in Gaosha fare in comparison to others in Hunan? Most recently in 2001-2014, street construction in Gaosha was 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, street construction in Gaosha has become more connected. Gaosha ranked 64th in 1975, 85th in 1976-1990, 47th in 1991-2000 and 71st in 2001-2014.

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

How do development practices in Gaosha fare in comparison to others in China? Most recently in 2001-2014, street construction in Gaosha was the 1210th-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 Gaosha has become more connected. Gaosha ranked 931st in 1975, 1395th in 1976-1990, 845th in 1991-2000 and 1210th in 2001-2014.

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

To date, Gaosha is the 95th-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 Gaosha has become more connected. Gaosha ranked 64th in 1975, 87th in 1976-1990, 88th in 1991-2000 and 95th in 2001-2014.

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

To date, Gaosha is the 1528th-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 Gaosha has become more connected. Gaosha ranked 931st in 1975, 1450th in 1976-1990, 1471st in 1991-2000 and 1528th in 2001-2014.

As of 2015, Gaosha had a built-up area of 2.24 square kilometers, and a population of 66451 people.

These are some other cities with approximately the same population: