Street-network Sprawl in Anchau, 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.

Anchau: city in Kaduna, 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 Anchau, Nigeria on the sprawlmap

Most recent snapshot: Taking into account the entire (i.e. aggregate) street network in Anchau as of 2014, the overall level of street-network sprawl is -1.42, which is very well-connected.

Trends in street network construction: The SNDis of street construction for the respective time periods are nan, -2.32, nan and -1.31. Data was not available in 1975 and 1991-2000.

Quantity of street network construction: The street network in Anchau spans a total of 36 kilometers. It is dominated by roads constructed in 2001-2014. These roads have an SNDi of -1.31, 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 nan, -2.22, -2.22 and -1.42. Data was not available in 1975.

Anchau and Kaduna 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 Kaduna peaked in 1991-2000.

How do development practices in Anchau fare in comparison to others in Kaduna? Most recently in 2001-2014, street construction in Anchau was the 12th-most disconnected out of the 14 cities in Kaduna. Anchau ranked 14th in 1976-1990 and 12th in 2001-2014. There was no ranking in 1975 and 1991-2000 due to unavailable data.

Anchau 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 Anchau fare in comparison to others in Nigeria? Most recently in 2001-2014, street construction in Anchau was the 377th-most disconnected out of the 411 cities in Nigeria. Anchau ranked 373rd in 1976-1990 and 377th in 2001-2014. There was no ranking in 1975 and 1991-2000 due to unavailable data.

Anchau and Kaduna do not follow the same trend in the disconnectivity of their aggregate street networks. There was not enough data from the city, while the SNDi of street constructions in Kaduna rose steadily.

To date, Anchau is the 14th-most disconnected out of the 14 cities in Kaduna. Its position in the ranks since 1975 has not changed. Anchau ranked 14th in 1976-1990, 14th in 1991-2000 and 14th in 2001-2014. There was no ranking in 1975 due to unavailable data.

Anchau and Nigeria do not follow the same trend in the disconnectivity of their aggregate street networks. There was not enough data from the city, while the SNDi of street constructions in Nigeria rose steadily.

To date, Anchau is the 408th-most disconnected out of the 411 cities in Nigeria. Its position in the ranks since 1975 has fallen; relative to other cities in Nigeria, the street network in Anchau has become more connected. Anchau ranked 386th in 1976-1990, 391st in 1991-2000 and 408th in 2001-2014. There was no ranking in 1975 due to unavailable data.

As of 2015, Anchau had a built-up area of 1.46 square kilometers, and a population of 64864 people.

These are some other cities with approximately the same population: