Street-network Sprawl in Xihu Township, Taiwan

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.

Xihu Township: city in Taiwan, Taiwan

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 Xihu Township, Taiwan on the sprawlmap

Most recent snapshot: Taking into account the entire (i.e. aggregate) street network in Xihu Township as of 2014, the overall level of street-network sprawl is -0.69, which is very well-connected.

Trends in street network construction: The SNDis of street construction for the respective time periods are -0.71, nan, -0.4 and nan. Data was not available in 1976-1990 and 2001-2014.

Quantity of street network construction: The street network in Xihu Township spans a total of 119 kilometers. It is dominated by roads constructed prior to 1975. These roads have an SNDi of -0.71, which is very 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 -0.71, -0.71, -0.69 and -0.69. Overall, the SNDi of the aggregate street network has risen: the street network in Xihu Township has become more disconnected.

Xihu Township and Taiwan 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 Taiwan peaked in 1976-1990.

How do development practices in Xihu Township fare in comparison to others in Taiwan? out of the 15 cities in Taiwan. Xihu Township ranked 15th in 1975 and 10th in 1991-2000. There was no ranking in 1976-1990 and 2001-2014 due to unavailable data.

Xihu Township and Taiwan 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 Taiwan followed a zig-zag trend with an overall increase.

How do development practices in Xihu Township fare in comparison to others in Taiwan? out of the 21 cities in Taiwan. Xihu Township ranked 21st in 1975 and 15th in 1991-2000. There was no ranking in 1976-1990 and 2001-2014 due to unavailable data.

Xihu Township and Taiwan do not follow the same trend in the disconnectivity of their aggregate street networks. The SNDi in Xihu Township rose steadily, while the SNDi of street constructions in Taiwan rose steadily.

To date, Xihu Township is the 15th-most disconnected out of the 15 cities in Taiwan. Its position in the ranks since 1975 has not changed. Xihu Township ranked 15th in 1975, 15th in 1976-1990, 15th in 1991-2000 and 15th in 2001-2014.

Xihu Township and Taiwan do not follow the same trend in the disconnectivity of their aggregate street networks. The SNDi in Xihu Township rose steadily, while the SNDi of street constructions in Taiwan rose steadily.

To date, Xihu Township is the 21st-most disconnected out of the 21 cities in Taiwan. Its position in the ranks since 1975 has not changed. Xihu Township ranked 21st in 1975, 21st in 1976-1990, 21st in 1991-2000 and 21st in 2001-2014.

As of 2015, Xihu Township had a built-up area of 6.34 square kilometers, and a population of 63896 people.

These are some other cities with approximately the same population: