Street-network Sprawl in Dajie, 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.

Dajie: city in Yunnan, 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 Dajie, China on the sprawlmap

Most recent snapshot: Taking into account the entire (i.e. aggregate) street network in Dajie as of 2014, the overall level of street-network sprawl is 0.8, which is relatively well-connected.

Trends in street network construction: The SNDis of street construction for the respective time periods are 0.7, 1.24, nan and nan. Data was not available in 1991-2000 and 2001-2014.

Quantity of street network construction: The street network in Dajie spans a total of 120 kilometers. It is dominated by roads constructed prior to 1975. These roads have an SNDi of 0.7, 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 0.7, 0.82, 0.82 and 0.8. The aggregate street network in Dajie increased in disconnectivity initially,but the trend has turned around after 1990.

Dajie and Yunnan 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 Yunnan rose steadily.

How do development practices in Dajie fare in comparison to others in Yunnan? out of the 56 cities in Yunnan. Its position in the ranks since 1975 has not changed. Dajie ranked 35th in 1975 and 35th in 1976-1990. There was no ranking in 1991-2000 and 2001-2014 due to unavailable data.

Dajie 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 Dajie fare in comparison to others in China? 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 Dajie has become more connected. Dajie ranked 932nd in 1975 and 985th in 1976-1990. There was no ranking in 1991-2000 and 2001-2014 due to unavailable data.

Dajie and Yunnan do not follow the same trend in the disconnectivity of their aggregate street networks. The SNDi in Dajie peaked in 1976-1990, while the SNDi of street constructions in Yunnan rose steadily.

To date, Dajie is the 51st-most disconnected out of the 56 cities in Yunnan. Its position in the ranks since 1975 has fallen; relative to other cities in Yunnan, the street network in Dajie has become more connected. Dajie ranked 35th in 1975, 44th in 1976-1990, 47th in 1991-2000 and 51st in 2001-2014.

Dajie and China do not follow the same trend in the disconnectivity of their aggregate street networks. The SNDi in Dajie peaked in 1976-1990, while the SNDi of street constructions in China peaked in 1976-1990.

To date, Dajie is the 1312th-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 Dajie has become more connected. Dajie ranked 932nd in 1975, 1219th in 1976-1990, 1238th in 1991-2000 and 1312th in 2001-2014.

As of 2015, Dajie had a built-up area of 10.14 square kilometers, and a population of 97123 people.

These are some other cities with approximately the same population: