Street-network Sprawl in Ouled Djellal, Algeria

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.

Ouled Djellal: city in Biskra, Algeria

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 Ouled Djellal, Algeria on the sprawlmap

Most recent snapshot: Taking into account the entire (i.e. aggregate) street network in Ouled Djellal as of 2014, the overall level of street-network sprawl is 0.64, which is relatively well-connected.

Trends in street network construction: The SNDis of street construction for the respective time periods are 0.81, nan, 0.37 and 1.51. Data was not available in 1976-1990.

Quantity of street network construction: The street network in Ouled Djellal spans a total of 159 kilometers. It is dominated by roads constructed in 1991-2000. These roads have an SNDi of 0.37, 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 0.81, 0.81, 0.58 and 0.64. Disconnectivity in Ouled Djellal's street network follows a zig-zag trend. In 1991-2000, the city was most disconnected; while it was most connected in 1975.

Ouled Djellal and Biskra 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 Biskra followed a zig-zag trend with an overall decrease.

How do development practices in Ouled Djellal fare in comparison to others in Biskra? Most recently in 2001-2014, street construction in Ouled Djellal was the 1st-most disconnected out of the 3 cities in Biskra. Its position in the ranks since 1975 has risen; relative to other cities in Biskra, street construction in Ouled Djellal has become more disconnected. Ouled Djellal ranked 2nd in 1975, 2nd in 1991-2000 and 1st in 2001-2014. There was no ranking in 1976-1990 due to unavailable data.

Ouled Djellal and Algeria 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 Algeria was at its lowest in 1976-1990.

How do development practices in Ouled Djellal fare in comparison to others in Algeria? Most recently in 2001-2014, street construction in Ouled Djellal was the 64th-most disconnected out of the 95 cities in Algeria. Its position in the ranks since 1975 has risen; relative to other cities in Algeria, street construction in Ouled Djellal has become more disconnected. Ouled Djellal ranked 49th in 1975, 78th in 1991-2000 and 64th in 2001-2014. There was no ranking in 1976-1990 due to unavailable data.

Ouled Djellal and Biskra do not follow the same trend in the disconnectivity of their aggregate street networks. The SNDi in Ouled Djellal followed a zig-zag trend with an overall decrease, while the SNDi of street constructions in Biskra followed a zig-zag trend with an overall decrease.

To date, Ouled Djellal is the 2nd-most disconnected out of the 3 cities in Biskra. Its position in the ranks since 1975 has not changed. Ouled Djellal ranked 2nd in 1975, 2nd in 1976-1990, 2nd in 1991-2000 and 2nd in 2001-2014.

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

To date, Ouled Djellal is the 76th-most disconnected out of the 95 cities in Algeria. Its position in the ranks since 1975 has fallen; relative to other cities in Algeria, the street network in Ouled Djellal has become more connected. Ouled Djellal ranked 49th in 1975, 64th in 1976-1990, 77th in 1991-2000 and 76th in 2001-2014.

As of 2015, Ouled Djellal had a built-up area of 4.5 square kilometers, and a population of 75252 people.

These are some other cities with approximately the same population: