Street-network Sprawl in Ngala, 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.

Ngala: city in Borno, 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 Ngala, Nigeria on the sprawlmap

Most recent snapshot: Taking into account the entire (i.e. aggregate) street network in Ngala as of 2014, the overall level of street-network sprawl is 0.31, which is very well-connected.

Trends in street network construction: The SNDis of street construction for the respective time periods are nan, 1.02, -0.16 and 0.37. Data was not available in 1975.

Quantity of street network construction: The street network in Ngala spans a total of 41 kilometers. It is dominated by roads constructed prior to 1975. These roads have an SNDi of nan, 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, 1.02, 0.01 and 0.31. Data was not available in 1975.

Ngala and Borno 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 Borno was at its lowest in 1976-1990.

How do development practices in Ngala fare in comparison to others in Borno? Most recently in 2001-2014, street construction in Ngala was the 12th-most disconnected out of the 17 cities in Borno. Its position in the ranks since 1975 has fallen; relative to other cities in Borno, street construction in Ngala has become more connected. Ngala ranked 4th in 1976-1990, 13th in 1991-2000 and 12th in 2001-2014. There was no ranking in 1975 due to unavailable data.

Ngala 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 Ngala fare in comparison to others in Nigeria? Most recently in 2001-2014, street construction in Ngala was the 331st-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 Ngala has become more connected. Ngala ranked 228th in 1976-1990, 251st in 1991-2000 and 331st in 2001-2014. There was no ranking in 1975 due to unavailable data.

Ngala and Borno 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 Borno was at its lowest in 1976-1990.

To date, Ngala is the 9th-most disconnected out of the 17 cities in Borno. Its position in the ranks since 1975 has fallen; relative to other cities in Borno, the street network in Ngala has become more connected. Ngala ranked 4th in 1976-1990, 8th in 1991-2000 and 9th in 2001-2014. There was no ranking in 1975 due to unavailable data.

Ngala 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, Ngala is the 328th-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 Ngala has become more connected. Ngala ranked 224th in 1976-1990, 311th in 1991-2000 and 328th in 2001-2014. There was no ranking in 1975 due to unavailable data.

As of 2015, Ngala had a built-up area of 0.63 square kilometers, and a population of 54843 people.

These are some other cities with approximately the same population: