Street-network Sprawl in Jinchang, 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.

Jinchang: city in Gansu, 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 Jinchang, China on the sprawlmap

Most recent snapshot: Taking into account the entire (i.e. aggregate) street network in Jinchang as of 2014, the overall level of street-network sprawl is 1.19, which is relatively well-connected.

Trends in street network construction: The SNDis of street construction for the respective time periods are 2.13, 0.43, 0.18 and 1.6. The disconnectivity of new streets constructed in Jinchang fell, then rose. In 1991-2000, new street layouts were the most connected.

Quantity of street network construction: The street network in Jinchang spans a total of 132 kilometers. It is dominated by roads constructed prior to 1975. These roads have an SNDi of 2.13, 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 2.13, 1.21, 1.16 and 1.19. The SNDi of the aggregate street network in fell at first, but Jinchang has worsened in disconnectivity since 2000.

Jinchang and Gansu 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 Jinchang fare in comparison to others in Gansu? Most recently in 2001-2014, street construction in Jinchang was the 24th-most disconnected out of the 34 cities in Gansu. Its position in the ranks since 1975 has fallen; relative to other cities in Gansu, street construction in Jinchang has become more connected. Jinchang ranked 14th in 1975, 27th in 1976-1990, 27th in 1991-2000 and 24th in 2001-2014.

Jinchang and China do not follow the same trend in the disconnectivity of their street network constructions. The SNDi in Jinchang 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 Jinchang fare in comparison to others in China? Most recently in 2001-2014, street construction in Jinchang was the 818th-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 Jinchang has become more connected. Jinchang ranked 457th in 1975, 1253rd in 1976-1990, 1049th in 1991-2000 and 818th in 2001-2014.

Jinchang and Gansu do not follow the same trend in the disconnectivity of their aggregate street networks. The SNDi in Jinchang was at its lowest in 1991-2000, while the SNDi of street constructions in Gansu fell steadily.

To date, Jinchang is the 28th-most disconnected out of the 34 cities in Gansu. Its position in the ranks since 1975 has fallen; relative to other cities in Gansu, the street network in Jinchang has become more connected. Jinchang ranked 14th in 1975, 26th in 1976-1990, 27th in 1991-2000 and 28th in 2001-2014.

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

To date, Jinchang is the 1122nd-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 Jinchang has become more connected. Jinchang ranked 457th in 1975, 1041st in 1976-1990, 1079th in 1991-2000 and 1122nd in 2001-2014.

As of 2015, Jinchang had a built-up area of 9.9 square kilometers, and a population of 155674 people.

These are some other cities with approximately the same population: