Street-network Sprawl in Tonghe, 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.

Tonghe: city in Heilongjiang, 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 Tonghe, China on the sprawlmap

Most recent snapshot: Taking into account the entire (i.e. aggregate) street network in Tonghe as of 2014, the overall level of street-network sprawl is 0.67, which is relatively well-connected.

Trends in street network construction: The SNDis of street construction for the respective time periods are 0.63, nan, nan and 1.6. Data was not available in 1976-1990 and 1991-2000.

Quantity of street network construction: The street network in Tonghe spans a total of 70 kilometers. It is dominated by roads constructed prior to 1975. These roads have an SNDi of 0.63, 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 0.63, 0.63, 0.68 and 0.67. Disconnectivity in Tonghe's street network follows a zig-zag trend. In 1975, the city was most disconnected; while it was most connected in 1991-2000.

Tonghe and Heilongjiang 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 Heilongjiang peaked in 1976-1990.

How do development practices in Tonghe fare in comparison to others in Heilongjiang? Most recently in 2001-2014, street construction in Tonghe was the 18th-most disconnected out of the 52 cities in Heilongjiang. Tonghe ranked 42nd in 1975 and 18th in 2001-2014. There was no ranking in 1976-1990 and 1991-2000 due to unavailable data.

Tonghe 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 Tonghe fare in comparison to others in China? Most recently in 2001-2014, street construction in Tonghe was the 820th-most disconnected out of the 1651 cities in China. Tonghe ranked 944th in 1975 and 820th in 2001-2014. There was no ranking in 1976-1990 and 1991-2000 due to unavailable data.

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

To date, Tonghe is the 45th-most disconnected out of the 52 cities in Heilongjiang. Its position in the ranks since 1975 has fallen; relative to other cities in Heilongjiang, the street network in Tonghe has become more connected. Tonghe ranked 42nd in 1975, 46th in 1976-1990, 44th in 1991-2000 and 45th in 2001-2014.

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

To date, Tonghe is the 1378th-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 Tonghe has become more connected. Tonghe ranked 944th in 1975, 1302nd in 1976-1990, 1291st in 1991-2000 and 1378th in 2001-2014.

As of 2015, Tonghe had a built-up area of 6.82 square kilometers, and a population of 54964 people.

These are some other cities with approximately the same population: