Street-network Sprawl in Yangjiang, 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.

Yangjiang: city in Guangdong, 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 Yangjiang, China on the sprawlmap

Most recent snapshot: Taking into account the entire (i.e. aggregate) street network in Yangjiang as of 2014, the overall level of street-network sprawl is 2.45, which is in the 40th to 60th percentile of disconnectedness.

Trends in street network construction: The SNDis of street construction for the respective time periods are 5.21, 3.34, 1.39 and 2.79. The disconnectivity of new streets constructed in Yangjiang fell, then rose. In 1991-2000, new street layouts were the most connected.

Quantity of street network construction: The street network in Yangjiang spans a total of 441 kilometers. The period with the greatest volume of street construction was 1991-2000. These roads have an SNDi of 1.39, 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 5.21, 3.53, 2.38 and 2.45. The SNDi of the aggregate street network in fell at first, but Yangjiang has worsened in disconnectivity since 2000.

Yangjiang and Guangdong follow the same trend in the disconnectivity of their street network constructions. The SNDi for both of these was at its lowest in 1991-2000.

How do development practices in Yangjiang fare in comparison to others in Guangdong? Most recently in 2001-2014, street construction in Yangjiang was the 37th-most disconnected out of the 109 cities in Guangdong. Its position in the ranks since 1975 has fallen; relative to other cities in Guangdong, street construction in Yangjiang has become more connected. Yangjiang ranked 10th in 1975, 21st in 1976-1990, 53rd in 1991-2000 and 37th in 2001-2014.

Yangjiang and China do not follow the same trend in the disconnectivity of their street network constructions. The SNDi in Yangjiang was at its lowest in 1991-2000, while the SNDi of street constructions in China followed a zig-zag trend with an overall decrease.

How do development practices in Yangjiang fare in comparison to others in China? Most recently in 2001-2014, street construction in Yangjiang was the 439th-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 Yangjiang has become more connected. Yangjiang ranked 43rd in 1975, 242nd in 1976-1990, 662nd in 1991-2000 and 439th in 2001-2014.

Yangjiang and Guangdong follow the same trend in the disconnectivity of their aggregate street networks. The SNDi for both of these was at its lowest in 1991-2000.

To date, Yangjiang is the 42nd-most disconnected out of the 109 cities in Guangdong. Its position in the ranks since 1975 has fallen; relative to other cities in Guangdong, the street network in Yangjiang has become more connected. Yangjiang ranked 10th in 1975, 22nd in 1976-1990, 40th in 1991-2000 and 42nd in 2001-2014.

Yangjiang and China do not follow the same trend in the disconnectivity of their aggregate street networks. The SNDi in Yangjiang was at its lowest in 1991-2000, while the SNDi of street constructions in China peaked in 1976-1990.

To date, Yangjiang is the 502nd-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 Yangjiang has become more connected. Yangjiang ranked 43rd in 1975, 168th in 1976-1990, 484th in 1991-2000 and 502nd in 2001-2014.

As of 2015, Yangjiang had a built-up area of 40.59 square kilometers, and a population of 445967 people.

These are some other cities with approximately the same population: