Street-network Sprawl in Lenasia, South Africa

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.

Lenasia: city in Gauteng, South Africa

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 Lenasia, South Africa on the sprawlmap

Most recent snapshot: Taking into account the entire (i.e. aggregate) street network in Lenasia as of 2014, the overall level of street-network sprawl is 1.92, which is relatively well-connected.

Trends in street network construction: The SNDis of street construction for the respective time periods are 1.79, 2.13, 4.5 and nan. Data was not available in 2001-2014.

Quantity of street network construction: The street network in Lenasia spans a total of 201 kilometers. It is dominated by roads constructed prior to 1975. These roads have an SNDi of 1.79, 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 1.79, 1.86, 1.92 and 1.92. Overall, the SNDi of the aggregate street network has risen: the street network in Lenasia has become more disconnected. This increase has slowed: between 1975 and 1976-1990, SNDi rose by 0.07 points, but between 1991-2000 and 2001-2014, it rose by just 0.0.

Lenasia and Gauteng 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 Gauteng rose steadily.

How do development practices in Lenasia fare in comparison to others in Gauteng? out of the 19 cities in Gauteng. Its position in the ranks since 1975 has risen; relative to other cities in Gauteng, street construction in Lenasia has become more disconnected. Lenasia ranked 16th in 1975, 16th in 1976-1990 and 5th in 1991-2000. There was no ranking in 2001-2014 due to unavailable data.

Lenasia and South Africa 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 South Africa followed a zig-zag trend with an overall increase.

How do development practices in Lenasia fare in comparison to others in South Africa? out of the 77 cities in South Africa. Its position in the ranks since 1975 has risen; relative to other cities in South Africa, street construction in Lenasia has become more disconnected. Lenasia ranked 47th in 1975, 63rd in 1976-1990 and 24th in 1991-2000. There was no ranking in 2001-2014 due to unavailable data.

Lenasia and Gauteng follow the same trend in the disconnectivity of their aggregate street networks. The SNDi for both of these rose steadily.

To date, Lenasia is the 19th-most disconnected out of the 19 cities in Gauteng. Its position in the ranks since 1975 has fallen; relative to other cities in Gauteng, the street network in Lenasia has become more connected. Lenasia ranked 16th in 1975, 18th in 1976-1990, 18th in 1991-2000 and 19th in 2001-2014.

Lenasia and South Africa follow the same trend in the disconnectivity of their aggregate street networks. The SNDi for both of these rose steadily.

To date, Lenasia is the 72nd-most disconnected out of the 77 cities in South Africa. Its position in the ranks since 1975 has fallen; relative to other cities in South Africa, the street network in Lenasia has become more connected. Lenasia ranked 47th in 1975, 64th in 1976-1990, 72nd in 1991-2000 and 72nd in 2001-2014.

As of 2015, Lenasia had a built-up area of 7.38 square kilometers, and a population of 85392 people.

These are some other cities with approximately the same population: