Street-network Sprawl in Farafangana, Madagascar

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.

Farafangana: city in Fianarantsoa, Madagascar

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 Farafangana, Madagascar on the sprawlmap

Most recent snapshot: Taking into account the entire (i.e. aggregate) street network in Farafangana as of 2014, the overall level of street-network sprawl is 1.28, which is relatively well-connected.

Trends in street network construction: The SNDis of street construction for the respective time periods are 0.54, 2.09, nan and nan. Data was not available in 1991-2000 and 2001-2014.

Quantity of street network construction: The street network in Farafangana spans a total of 30 kilometers. It is dominated by roads constructed prior to 1975. These roads have an SNDi of 0.54, 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 0.54, 0.99, 0.99 and 1.28. Overall, the SNDi of the aggregate street network has risen: the street network in Farafangana has become more disconnected. This increase has slowed: between 1975 and 1976-1990, SNDi rose by 0.46 points, but between 1991-2000 and 2001-2014, it rose by just 0.29.

Farafangana and Fianarantsoa 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 Fianarantsoa followed a zig-zag trend with an overall increase.

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

Farafangana and Madagascar 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 Madagascar followed a zig-zag trend with an overall increase.

How do development practices in Farafangana fare in comparison to others in Madagascar? out of the 12 cities in Madagascar. Its position in the ranks since 1975 has risen; relative to other cities in Madagascar, street construction in Farafangana has become more disconnected. Farafangana ranked 7th in 1975 and 4th in 1976-1990. There was no ranking in 1991-2000 and 2001-2014 due to unavailable data.

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

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

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

To date, Farafangana is the 9th-most disconnected out of the 12 cities in Madagascar. Its position in the ranks since 1975 has fallen; relative to other cities in Madagascar, the street network in Farafangana has become more connected. Farafangana ranked 7th in 1975, 8th in 1976-1990, 10th in 1991-2000 and 9th in 2001-2014.

As of 2015, Farafangana had a built-up area of 0.9 square kilometers, and a population of 61218 people.

These are some other cities with approximately the same population: