Street-network Sprawl in Nchelenge, Zambia

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.

Nchelenge: city in Luapula, Zambia

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 Nchelenge, Zambia on the sprawlmap

Most recent snapshot: Taking into account the entire (i.e. aggregate) street network in Nchelenge as of 2014, the overall level of street-network sprawl is 3.62, which is highly disconnected.

Trends in street network construction: The SNDis of street construction for the respective time periods are 7.17, 1.31, nan and 3.68. Data was not available in 1991-2000.

Quantity of street network construction: The street network in Nchelenge spans a total of 38 kilometers. It is dominated by roads constructed in 2001-2014. These roads have an SNDi of 3.68, 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 7.17, 4.6, 4.2 and 3.62. Overall, the SNDi of the aggregate street network has fallen: the street network in Nchelenge has become more connected.

Nchelenge and Luapula 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 Luapula followed a zig-zag trend with an overall increase.

How do development practices in Nchelenge fare in comparison to others in Luapula? Most recently in 2001-2014, street construction in Nchelenge was the 1st-most disconnected out of the 2 cities in Luapula. Its position in the ranks since 1975 has not changed. Nchelenge ranked 1st in 1975, 1st in 1976-1990 and 1st in 2001-2014. There was no ranking in 1991-2000 due to unavailable data.

Nchelenge and Zambia 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 Zambia rose steadily.

How do development practices in Nchelenge fare in comparison to others in Zambia? Most recently in 2001-2014, street construction in Nchelenge was the 6th-most disconnected out of the 38 cities in Zambia. Its position in the ranks since 1975 has fallen; relative to other cities in Zambia, street construction in Nchelenge has become more connected. Nchelenge ranked 1st in 1975, 26th in 1976-1990 and 6th in 2001-2014. There was no ranking in 1991-2000 due to unavailable data.

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

To date, Nchelenge is the 1st-most disconnected out of the 2 cities in Luapula. Its position in the ranks since 1975 has not changed. Nchelenge ranked 1st in 1975, 1st in 1976-1990, 1st in 1991-2000 and 1st in 2001-2014.

Nchelenge and Zambia do not follow the same trend in the disconnectivity of their aggregate street networks. The SNDi in Nchelenge fell steadily, while the SNDi of street constructions in Zambia rose steadily.

To date, Nchelenge is the 4th-most disconnected out of the 38 cities in Zambia. Its position in the ranks since 1975 has fallen; relative to other cities in Zambia, the street network in Nchelenge has become more connected. Nchelenge ranked 1st in 1975, 2nd in 1976-1990, 3rd in 1991-2000 and 4th in 2001-2014.

As of 2015, Nchelenge had a built-up area of 1.6 square kilometers, and a population of 117455 people.

These are some other cities with approximately the same population: