Street-network Sprawl in Andoany, 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.

Andoany: city in Antsiranana, 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 Andoany, Madagascar on the sprawlmap

Most recent snapshot: Taking into account the entire (i.e. aggregate) street network in Andoany as of 2014, the overall level of street-network sprawl is 1.38, which is relatively well-connected.

Trends in street network construction: The SNDis of street construction for the respective time periods are 0.99, nan, nan and nan. Data was not available in 1976-1990, 1991-2000 and 2001-2014.

Quantity of street network construction: The street network in Andoany spans a total of 17 kilometers. It is dominated by roads constructed prior to 1975. These roads have an SNDi of 0.99, 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 0.99, 0.88, 1.05 and 1.38. The SNDi of the aggregate street network in fell at first, but Andoany has worsened in disconnectivity since 1990.

Andoany and Antsiranana 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 Antsiranana followed a zig-zag trend with an overall increase.

How do development practices in Andoany fare in comparison to others in Antsiranana? out of the 1 cities in Antsiranana. Andoany ranked 1st in 1975. There was no ranking in 1976-1990, 1991-2000, and 2001-2014 due to unavailable data.

Andoany 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 Andoany fare in comparison to others in Madagascar? out of the 12 cities in Madagascar. Andoany ranked 6th in 1975. There was no ranking in 1976-1990, 1991-2000, and 2001-2014 due to unavailable data.

Andoany and Antsiranana follow the same trend in the disconnectivity of their aggregate street networks. The SNDi for both of these was at its lowest in 1976-1990.

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

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

To date, Andoany is the 8th-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 Andoany has become more connected. Andoany ranked 6th in 1975, 9th in 1976-1990, 7th in 1991-2000 and 8th in 2001-2014.

As of 2015, Andoany had a built-up area of 0.92 square kilometers, and a population of 53136 people.

These are some other cities with approximately the same population: