Street-network Sprawl in Porto Amboim, Angola

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.

Porto Amboim: city in Cuanza Sul, Angola

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 Porto Amboim, Angola on the sprawlmap

Most recent snapshot: Taking into account the entire (i.e. aggregate) street network in Porto Amboim as of 2014, the overall level of street-network sprawl is 2.77, which is in the 40th to 60th percentile of disconnectedness.

Trends in street network construction: The SNDis of street construction for the respective time periods are 2.75, 2.77, 2.87 and 2.66. Street construction in Porto Amboim increased in disconnectivity initially but has since improved. The streets constructed in 1991-2000 were the most disconnected.

Quantity of street network construction: The street network in Porto Amboim spans a total of 120 kilometers. It is dominated by roads constructed in 1976-1990. These roads have an SNDi of 2.77, which is in the 40th to 60th percentile of disconnectedness.

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 2.75, 2.77, 2.77 and 2.77. The aggregate street network in Porto Amboim increased in disconnectivity initially,but the trend has turned around after 2000.

Porto Amboim and Cuanza Sul follow the same trend in the disconnectivity of their street network constructions. The SNDi for both of these peaked in 1991-2000.

How do development practices in Porto Amboim fare in comparison to others in Cuanza Sul? Most recently in 2001-2014, street construction in Porto Amboim was the 4th-most disconnected out of the 6 cities in Cuanza Sul. Its position in the ranks since 1975 has fallen; relative to other cities in Cuanza Sul, street construction in Porto Amboim has become more connected. Porto Amboim ranked 2nd in 1975, 3rd in 1976-1990, 2nd in 1991-2000 and 4th in 2001-2014.

Porto Amboim and Angola do not follow the same trend in the disconnectivity of their street network constructions. The SNDi in Porto Amboim peaked in 1991-2000, while the SNDi of street constructions in Angola peaked in 1976-1990.

How do development practices in Porto Amboim fare in comparison to others in Angola? Most recently in 2001-2014, street construction in Porto Amboim was the 21st-most disconnected out of the 51 cities in Angola. Its position in the ranks since 1975 has fallen; relative to other cities in Angola, street construction in Porto Amboim has become more connected. Porto Amboim ranked 7th in 1975, 11th in 1976-1990, 9th in 1991-2000 and 21st in 2001-2014.

Porto Amboim and Cuanza Sul follow the same trend in the disconnectivity of their aggregate street networks. The SNDi for both of these peaked in 1991-2000.

To date, Porto Amboim is the 3rd-most disconnected out of the 6 cities in Cuanza Sul. Its position in the ranks since 1975 has fallen; relative to other cities in Cuanza Sul, the street network in Porto Amboim has become more connected. Porto Amboim ranked 2nd in 1975, 3rd in 1976-1990, 3rd in 1991-2000 and 3rd in 2001-2014.

Porto Amboim and Angola follow the same trend in the disconnectivity of their aggregate street networks. The SNDi for both of these peaked in 1991-2000.

To date, Porto Amboim is the 17th-most disconnected out of the 51 cities in Angola. Its position in the ranks since 1975 has fallen; relative to other cities in Angola, the street network in Porto Amboim has become more connected. Porto Amboim ranked 7th in 1975, 11th in 1976-1990, 13th in 1991-2000 and 17th in 2001-2014.

As of 2015, Porto Amboim had a built-up area of 2.5 square kilometers, and a population of 74346 people.

These are some other cities with approximately the same population: