Street-network Sprawl in Guéckédou, Guinea

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.

Guéckédou: city in Nzérékoré, Guinea

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 Guéckédou, Guinea on the sprawlmap

Most recent snapshot: Taking into account the entire (i.e. aggregate) street network in Guéckédou as of 2014, the overall level of street-network sprawl is 2.85, 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 1.8, 2.27, 4.17 and 7.34. In each period, new street development in Guéckédou steadily grows more disconnected than in the last.

Quantity of street network construction: The street network in Guéckédou spans a total of 87 kilometers. It is dominated by roads constructed prior to 1975. These roads have an SNDi of 1.8, 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 1.8, 1.82, 2.71 and 2.85. Overall, the SNDi of the aggregate street network has risen: the street network in Guéckédou has become more disconnected.

Guéckédou and Nzérékoré do not follow the same trend in the disconnectivity of their street network constructions. The SNDi in Guéckédou rose steadily, while the SNDi of street constructions in Nzérékoré followed a zig-zag trend with an overall increase.

How do development practices in Guéckédou fare in comparison to others in Nzérékoré? Most recently in 2001-2014, street construction in Guéckédou was the 1st-most disconnected out of the 4 cities in Nzérékoré. Its position in the ranks since 1975 has risen; relative to other cities in Nzérékoré, street construction in Guéckédou has become more disconnected. Guéckédou ranked 4th in 1975, 3rd in 1976-1990, 3rd in 1991-2000 and 1st in 2001-2014.

Guéckédou and Guinea follow the same trend in the disconnectivity of their street network constructions. The SNDi for both of these rose steadily.

How do development practices in Guéckédou fare in comparison to others in Guinea? Most recently in 2001-2014, street construction in Guéckédou was the 1st-most disconnected out of the 18 cities in Guinea. Its position in the ranks since 1975 has risen; relative to other cities in Guinea, street construction in Guéckédou has become more disconnected. Guéckédou ranked 11th in 1975, 10th in 1976-1990, 3rd in 1991-2000 and 1st in 2001-2014.

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

To date, Guéckédou is the 4th-most disconnected out of the 4 cities in Nzérékoré. Its position in the ranks since 1975 has not changed. Guéckédou ranked 4th in 1975, 4th in 1976-1990, 4th in 1991-2000 and 4th in 2001-2014.

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

To date, Guéckédou is the 11th-most disconnected out of the 18 cities in Guinea. Its position in the ranks since 1975 has not changed. Guéckédou ranked 11th in 1975, 12th in 1976-1990, 8th in 1991-2000 and 11th in 2001-2014.

As of 2015, Guéckédou had a built-up area of 5.64 square kilometers, and a population of 65050 people.

These are some other cities with approximately the same population: