Street-network Sprawl in Zinder, Niger

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.

Zinder: city in Niger

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 Zinder, Niger on the sprawlmap

Most recent snapshot: Taking into account the entire (i.e. aggregate) street network in Zinder 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 0.03, 0.24, -0.61 and 1.32. Disconnectivity in street construction in Zinder follows a zig-zag trend. In 1991-2000, street construction was most disconnected, while construction was most connected in 2001-2014.

Quantity of street network construction: The street network in Zinder spans a total of 389 kilometers. It is dominated by roads constructed in 2001-2014. These roads have an SNDi of 1.32, 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 0.03, 0.1, -0.03 and 0.53. Disconnectivity in Zinder's street network follows a zig-zag trend. In 1991-2000, the city was most disconnected; while it was most connected in 2001-2014.

Zinder and Zinder follow the same trend in the disconnectivity of their street network constructions. The SNDi for both of these followed a zig-zag trend with an overall increase.

How do development practices in Zinder fare in comparison to others in Zinder? Most recently in 2001-2014, street construction in Zinder was the 1st-most disconnected out of the 2 cities in Zinder. Its position in the ranks since 1975 has not changed. Zinder ranked 1st in 1975, 1st in 1976-1990, 1st in 1991-2000 and 1st in 2001-2014.

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

How do development practices in Zinder fare in comparison to others in Niger? Most recently in 2001-2014, street construction in Zinder was the 7th-most disconnected out of the 21 cities in Niger. Its position in the ranks since 1975 has fallen; relative to other cities in Niger, street construction in Zinder has become more connected. Zinder ranked 5th in 1975, 4th in 1976-1990, 15th in 1991-2000 and 7th in 2001-2014.

Zinder and Zinder do not follow the same trend in the disconnectivity of their aggregate street networks. The SNDi in Zinder followed a zig-zag trend with an overall increase, while the SNDi of street constructions in Zinder rose steadily.

To date, Zinder is the 2nd-most disconnected out of the 2 cities in Zinder. Its position in the ranks since 1975 has fallen; relative to other cities in Zinder, the street network in Zinder has become more connected. Zinder ranked 1st in 1975, 2nd in 1976-1990, 2nd in 1991-2000 and 2nd in 2001-2014.

Zinder and Niger do not follow the same trend in the disconnectivity of their aggregate street networks. The SNDi in Zinder followed a zig-zag trend with an overall increase, while the SNDi of street constructions in Niger rose steadily.

To date, Zinder is the 7th-most disconnected out of the 21 cities in Niger. Its position in the ranks since 1975 has fallen; relative to other cities in Niger, the street network in Zinder has become more connected. Zinder ranked 5th in 1975, 7th in 1976-1990, 12th in 1991-2000 and 7th in 2001-2014.

As of 2015, Zinder had a built-up area of 14.57 square kilometers, and a population of 564388 people.

These are some other cities with approximately the same population: