Street-network Sprawl in Ankpa, 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.

Ankpa: city in Kogi, 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 Ankpa, Nigeria on the sprawlmap

Most recent snapshot: Taking into account the entire (i.e. aggregate) street network in Ankpa as of 2014, the overall level of street-network sprawl is 0.53, which is relatively well-connected.

Trends in street network construction: The SNDis of street construction for the respective time periods are -0.83, 0.24, 0.24 and 1.09. In each period, new street development in Ankpa steadily grows more disconnected than in the last. This increase has slowed: between 1975 and 1976-1990, SNDi rose by 1.08 points, but between 1991-2000 and 2001-2014, it rose by just 0.85.

Quantity of street network construction: The street network in Ankpa spans a total of 151 kilometers. It is dominated by roads constructed in 2001-2014. These roads have an SNDi of 1.09, which is relatively 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 -0.83, -0.04, -0.02 and 0.53. Overall, the SNDi of the aggregate street network has risen: the street network in Ankpa has become more disconnected. This increase has slowed: between 1975 and 1976-1990, SNDi rose by 0.8 points, but between 1991-2000 and 2001-2014, it rose by just 0.55.

Ankpa and Kogi do not follow the same trend in the disconnectivity of their street network constructions. The SNDi in Ankpa rose steadily, while the SNDi of street constructions in Kogi peaked in 1991-2000.

How do development practices in Ankpa fare in comparison to others in Kogi? Most recently in 2001-2014, street construction in Ankpa was the 9th-most disconnected out of the 9 cities in Kogi. Its position in the ranks since 1975 has fallen; relative to other cities in Kogi, street construction in Ankpa has become more connected. Ankpa ranked 5th in 1975, 7th in 1976-1990, 9th in 1991-2000 and 9th in 2001-2014.

Ankpa and Nigeria do not follow the same trend in the disconnectivity of their street network constructions. The SNDi in Ankpa rose steadily, while the SNDi of street constructions in Nigeria peaked in 1991-2000.

How do development practices in Ankpa fare in comparison to others in Nigeria? Most recently in 2001-2014, street construction in Ankpa was the 284th-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 Ankpa has become more connected. Ankpa ranked 234th in 1975, 270th in 1976-1990, 231st in 1991-2000 and 284th in 2001-2014.

Ankpa and Kogi follow the same trend in the disconnectivity of their aggregate street networks. The SNDi for both of these rose steadily.

To date, Ankpa is the 9th-most disconnected out of the 9 cities in Kogi. Its position in the ranks since 1975 has fallen; relative to other cities in Kogi, the street network in Ankpa has become more connected. Ankpa ranked 5th in 1975, 8th in 1976-1990, 8th in 1991-2000 and 9th in 2001-2014.

Ankpa and Nigeria follow the same trend in the disconnectivity of their aggregate street networks. The SNDi for both of these rose steadily.

To date, Ankpa is the 317th-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 Ankpa has become more connected. Ankpa ranked 234th in 1975, 295th in 1976-1990, 313th in 1991-2000 and 317th in 2001-2014.

As of 2015, Ankpa had a built-up area of 4.56 square kilometers, and a population of 180623 people.

These are some other cities with approximately the same population: