Street-network Sprawl in Onitu, 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.

Onitu: city in Rivers, 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 Onitu, Nigeria on the sprawlmap

Most recent snapshot: Taking into account the entire (i.e. aggregate) street network in Onitu as of 2014, the overall level of street-network sprawl is 7.83, which is highly disconnected.

Trends in street network construction: The SNDis of street construction for the respective time periods are nan, 3.78, nan and 8.97. Data was not available in 1975 and 1991-2000.

Quantity of street network construction: The street network in Onitu spans a total of 87 kilometers. It is dominated by roads constructed in 2001-2014. These roads have an SNDi of 8.97, 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 nan, 3.53, 3.53 and 7.83. Data was not available in 1975.

Onitu and Rivers 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 Rivers rose steadily.

How do development practices in Onitu fare in comparison to others in Rivers? Most recently in 2001-2014, street construction in Onitu was the 1st-most disconnected out of the 15 cities in Rivers. Onitu ranked 8th in 1976-1990 and 1st in 2001-2014. There was no ranking in 1975 and 1991-2000 due to unavailable data.

Onitu 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 Onitu fare in comparison to others in Nigeria? Most recently in 2001-2014, street construction in Onitu was the 4th-most disconnected out of the 411 cities in Nigeria. Onitu ranked 62nd in 1976-1990 and 4th in 2001-2014. There was no ranking in 1975 and 1991-2000 due to unavailable data.

Onitu and Rivers 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 Rivers rose steadily.

To date, Onitu is the 1st-most disconnected out of the 15 cities in Rivers. Its position in the ranks since 1975 has risen; relative to other cities in Rivers, the street network in Onitu has become more disconnected. Onitu ranked 7th in 1976-1990, 7th in 1991-2000 and 1st in 2001-2014. There was no ranking in 1975 due to unavailable data.

Onitu 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, Onitu is the 1st-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 Onitu has become more disconnected. Onitu ranked 45th in 1976-1990, 58th in 1991-2000 and 1st in 2001-2014. There was no ranking in 1975 due to unavailable data.

As of 2015, Onitu had a built-up area of 3.61 square kilometers, and a population of 134984 people.

These are some other cities with approximately the same population: