Street-network Sprawl in Zango, Nigeria

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.

Zango: city in Kano, Nigeria

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 Zango, Nigeria on the sprawlmap

Most recent snapshot: Taking into account the entire (i.e. aggregate) street network in Zango as of 2014, the overall level of street-network sprawl is 2.27, 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 -0.75, nan, nan and 4.35. Data was not available in 1976-1990 and 1991-2000.

Quantity of street network construction: The street network in Zango spans a total of 23 kilometers. It is dominated by roads constructed in 2001-2014. These roads have an SNDi of 4.35, which is highly disconnected.

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 -0.75, -0.94, -0.94 and 2.27. The SNDi of the aggregate street network in fell at first, but Zango has worsened in disconnectivity since 1990.

Zango and Kano 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 Kano peaked in 1976-1990.

How do development practices in Zango fare in comparison to others in Kano? Most recently in 2001-2014, street construction in Zango was the 3rd-most disconnected out of the 22 cities in Kano. Zango ranked 16th in 1975 and 3rd in 2001-2014. There was no ranking in 1976-1990 and 1991-2000 due to unavailable data.

Zango and Nigeria 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 Nigeria peaked in 1991-2000.

How do development practices in Zango fare in comparison to others in Nigeria? Most recently in 2001-2014, street construction in Zango was the 108th-most disconnected out of the 411 cities in Nigeria. Zango ranked 230th in 1975 and 108th in 2001-2014. There was no ranking in 1976-1990 and 1991-2000 due to unavailable data.

Zango and Kano do not follow the same trend in the disconnectivity of their aggregate street networks. The SNDi in Zango was at its lowest in 1976-1990, while the SNDi of street constructions in Kano rose steadily.

To date, Zango is the 4th-most disconnected out of the 22 cities in Kano. Its position in the ranks since 1975 has risen; relative to other cities in Kano, the street network in Zango has become more disconnected. Zango ranked 16th in 1975, 21st in 1976-1990, 20th in 1991-2000 and 4th in 2001-2014.

Zango and Nigeria do not follow the same trend in the disconnectivity of their aggregate street networks. The SNDi in Zango was at its lowest in 1976-1990, while the SNDi of street constructions in Nigeria rose steadily.

To date, Zango is the 177th-most disconnected out of the 411 cities in Nigeria. Its position in the ranks since 1975 has risen; relative to other cities in Nigeria, the street network in Zango has become more disconnected. Zango ranked 230th in 1975, 372nd in 1976-1990, 378th in 1991-2000 and 177th in 2001-2014.

As of 2015, Zango had a built-up area of 0.75 square kilometers, and a population of 55083 people.

These are some other cities with approximately the same population: