Street-network Sprawl in Ovwian, 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.

Ovwian: city in Delta, 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 Ovwian, Nigeria on the sprawlmap

Most recent snapshot: Taking into account the entire (i.e. aggregate) street network in Ovwian as of 2014, the overall level of street-network sprawl is 4.81, which is highly disconnected.

Trends in street network construction: The SNDis of street construction for the respective time periods are 5.88, 4.11, 5.97 and 7.61. The disconnectivity of new streets constructed in Ovwian fell, then rose. In 1976-1990, new street layouts were the most connected.

Quantity of street network construction: The street network in Ovwian spans a total of 214 kilometers. It is dominated by roads constructed in 1976-1990. These roads have an SNDi of 4.11, 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 5.88, 4.24, 4.55 and 4.81. The SNDi of the aggregate street network in fell at first, but Ovwian has worsened in disconnectivity since 1990.

Ovwian and Delta do not follow the same trend in the disconnectivity of their street network constructions. The SNDi in Ovwian was at its lowest in 1976-1990, while the SNDi of street constructions in Delta followed a zig-zag trend with an overall increase.

How do development practices in Ovwian fare in comparison to others in Delta? Most recently in 2001-2014, street construction in Ovwian was the 2nd-most disconnected out of the 16 cities in Delta. Its position in the ranks since 1975 has fallen; relative to other cities in Delta, street construction in Ovwian has become more connected. Ovwian ranked 1st in 1975, 5th in 1976-1990, 2nd in 1991-2000 and 2nd in 2001-2014.

Ovwian and Nigeria do not follow the same trend in the disconnectivity of their street network constructions. The SNDi in Ovwian was at its lowest in 1976-1990, while the SNDi of street constructions in Nigeria peaked in 1991-2000.

How do development practices in Ovwian fare in comparison to others in Nigeria? Most recently in 2001-2014, street construction in Ovwian was the 10th-most disconnected out of the 411 cities in Nigeria. Its position in the ranks since 1975 has fallen; relative to other cities in Nigeria, street construction in Ovwian has become more connected. Ovwian ranked 3rd in 1975, 50th in 1976-1990, 24th in 1991-2000 and 10th in 2001-2014.

Ovwian and Delta do not follow the same trend in the disconnectivity of their aggregate street networks. The SNDi in Ovwian was at its lowest in 1976-1990, while the SNDi of street constructions in Delta followed a zig-zag trend with an overall increase.

To date, Ovwian is the 4th-most disconnected out of the 16 cities in Delta. Its position in the ranks since 1975 has fallen; relative to other cities in Delta, the street network in Ovwian has become more connected. Ovwian ranked 1st in 1975, 4th in 1976-1990, 4th in 1991-2000 and 4th in 2001-2014.

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

To date, Ovwian is the 24th-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 Ovwian has become more connected. Ovwian ranked 3rd in 1975, 28th in 1976-1990, 26th in 1991-2000 and 24th in 2001-2014.

As of 2015, Ovwian had a built-up area of 11.79 square kilometers, and a population of 131934 people.

These are some other cities with approximately the same population: