Street-network Sprawl in Geidam, 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.

Geidam: city in Yobe, 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 Geidam, Nigeria on the sprawlmap

Most recent snapshot: Taking into account the entire (i.e. aggregate) street network in Geidam as of 2014, the overall level of street-network sprawl is -0.09, which is very well-connected.

Trends in street network construction: The SNDis of street construction for the respective time periods are 0.63, -0.53, 2.06 and 0.06. Disconnectivity in street construction in Geidam follows a zig-zag trend. In 1976-1990, street construction was most disconnected, while construction was most connected in 1991-2000.

Quantity of street network construction: The street network in Geidam spans a total of 118 kilometers. It is dominated by roads constructed in 1976-1990. These roads have an SNDi of -0.53, 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 0.63, -0.48, -0.19 and -0.09. The SNDi of the aggregate street network in fell at first, but Geidam has worsened in disconnectivity since 1990.

Geidam and Yobe do not follow the same trend in the disconnectivity of their street network constructions. The SNDi in Geidam followed a zig-zag trend with an overall decrease, while the SNDi of street constructions in Yobe rose steadily.

How do development practices in Geidam fare in comparison to others in Yobe? Most recently in 2001-2014, street construction in Geidam was the 6th-most disconnected out of the 7 cities in Yobe. Its position in the ranks since 1975 has fallen; relative to other cities in Yobe, street construction in Geidam has become more connected. Geidam ranked 1st in 1975, 5th in 1976-1990, 2nd in 1991-2000 and 6th in 2001-2014.

Geidam and Nigeria do not follow the same trend in the disconnectivity of their street network constructions. The SNDi in Geidam followed a zig-zag trend with an overall decrease, while the SNDi of street constructions in Nigeria peaked in 1991-2000.

How do development practices in Geidam fare in comparison to others in Nigeria? Most recently in 2001-2014, street construction in Geidam was the 342nd-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 Geidam has become more connected. Geidam ranked 169th in 1975, 328th in 1976-1990, 155th in 1991-2000 and 342nd in 2001-2014.

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

To date, Geidam is the 6th-most disconnected out of the 7 cities in Yobe. Its position in the ranks since 1975 has fallen; relative to other cities in Yobe, the street network in Geidam has become more connected. Geidam ranked 1st in 1975, 5th in 1976-1990, 5th in 1991-2000 and 6th in 2001-2014.

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

To date, Geidam is the 360th-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 Geidam has become more connected. Geidam ranked 169th in 1975, 338th in 1976-1990, 330th in 1991-2000 and 360th in 2001-2014.

As of 2015, Geidam had a built-up area of 2.45 square kilometers, and a population of 194654 people.

These are some other cities with approximately the same population: