Street-network Sprawl in Kunming, 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.

Kunming: 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 Kunming, China on the sprawlmap

Most recent snapshot: Taking into account the entire (i.e. aggregate) street network in Kunming as of 2014, the overall level of street-network sprawl is 2.58, 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 2.42, 3.92, 4.03 and 3.72. Street construction in Kunming increased in disconnectivity initially but has since improved. The streets constructed in 1991-2000 were the most disconnected.

Quantity of street network construction: The street network in Kunming spans a total of 2294 kilometers. It is dominated by roads constructed prior to 1975. These roads have an SNDi of 2.42, which is in the 40th to 60th percentile of disconnectedness.

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 2.42, 2.54, 2.55 and 2.58. Overall, the SNDi of the aggregate street network has risen: the street network in Kunming has become more disconnected. This increase has slowed: between 1975 and 1976-1990, SNDi rose by 0.12 points, but between 1991-2000 and 2001-2014, it rose by just 0.03.

Kunming and Yunnan do not follow the same trend in the disconnectivity of their street network constructions. The SNDi in Kunming peaked in 1991-2000, while the SNDi of street constructions in Yunnan rose steadily.

How do development practices in Kunming fare in comparison to others in Yunnan? Most recently in 2001-2014, street construction in Kunming was the 15th-most disconnected out of the 56 cities in Yunnan. Its position in the ranks since 1975 has fallen; relative to other cities in Yunnan, street construction in Kunming has become more connected. Kunming ranked 10th in 1975, 8th in 1976-1990, 9th in 1991-2000 and 15th in 2001-2014.

Kunming and China do not follow the same trend in the disconnectivity of their street network constructions. The SNDi in Kunming peaked 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 Kunming fare in comparison to others in China? Most recently in 2001-2014, street construction in Kunming was the 233rd-most disconnected out of the 1651 cities in China. Its position in the ranks since 1975 has risen; relative to other cities in China, street construction in Kunming has become more disconnected. Kunming ranked 388th in 1975, 145th in 1976-1990, 115th in 1991-2000 and 233rd in 2001-2014.

Kunming and Yunnan follow the same trend in the disconnectivity of their aggregate street networks. The SNDi for both of these rose steadily.

To date, Kunming is the 21st-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 Kunming has become more connected. Kunming ranked 10th in 1975, 16th in 1976-1990, 20th in 1991-2000 and 21st in 2001-2014.

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

To date, Kunming is the 442nd-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 Kunming has become more connected. Kunming ranked 388th in 1975, 437th in 1976-1990, 418th in 1991-2000 and 442nd in 2001-2014.

As of 2015, Kunming had a built-up area of 217.52 square kilometers, and a population of 3070466 people.

These are some other cities with approximately the same population: