Street-network Sprawl in Tamale, Ghana

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.

Tamale: city in Northern, Ghana

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 Tamale, Ghana on the sprawlmap

Most recent snapshot: Taking into account the entire (i.e. aggregate) street network in Tamale as of 2014, the overall level of street-network sprawl is 2.88, 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 2.31, 3.0, 2.99 and 3.26. Disconnectivity in street construction in Tamale follows a zig-zag trend. In 1975, street construction was most disconnected, while construction was most connected in 2001-2014.

Quantity of street network construction: The street network in Tamale spans a total of 592 kilometers. The period with the greatest volume of street construction was 2001-2014. These roads have an SNDi of 3.26, 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 2.31, 2.66, 2.73 and 2.88. Overall, the SNDi of the aggregate street network has risen: the street network in Tamale has become more disconnected. This increase has slowed: between 1975 and 1976-1990, SNDi rose by 0.36 points, but between 1991-2000 and 2001-2014, it rose by just 0.15.

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

How do development practices in Tamale fare in comparison to others in Northern? Most recently in 2001-2014, street construction in Tamale was the 1st-most disconnected out of the 8 cities in Northern. Its position in the ranks since 1975 has not changed. Tamale ranked 1st in 1975, 1st in 1976-1990, 1st in 1991-2000 and 1st in 2001-2014.

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

How do development practices in Tamale fare in comparison to others in Ghana? Most recently in 2001-2014, street construction in Tamale was the 33rd-most disconnected out of the 51 cities in Ghana. Its position in the ranks since 1975 has fallen; relative to other cities in Ghana, street construction in Tamale has become more connected. Tamale ranked 27th in 1975, 24th in 1976-1990, 26th in 1991-2000 and 33rd in 2001-2014.

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

To date, Tamale is the 1st-most disconnected out of the 8 cities in Northern. Its position in the ranks since 1975 has not changed. Tamale ranked 1st in 1975, 1st in 1976-1990, 1st in 1991-2000 and 1st in 2001-2014.

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

To date, Tamale is the 34th-most disconnected out of the 51 cities in Ghana. Its position in the ranks since 1975 has fallen; relative to other cities in Ghana, the street network in Tamale has become more connected. Tamale ranked 27th in 1975, 26th in 1976-1990, 29th in 1991-2000 and 34th in 2001-2014.

As of 2015, Tamale had a built-up area of 30.15 square kilometers, and a population of 370207 people.

These are some other cities with approximately the same population: